GROWTH RATES AND PREY-HANDLING BEHAVIOR OF

Transcription

GROWTH RATES AND PREY-HANDLING BEHAVIOR OF HATCHLING CORN SNAKES
PANTHEROPHIS GUTTATUS (COLUBRIDAE)
by
David A. Penning
An Abstract
of a thesis submitted in partial fulfillment
of the requirements for the degree of
Masters of Science
in the Department of Biology and Earth Science
University of Central Missouri
February, 2012
ABSTRACT
By
David A. Penning
Effects of prey mass on growth (length, girth, and mass) and prey-handling behavior of 18
hatchling corn snakes (Pantherophis guttatus) were studied in a laboratory setting. Hatchlings
were randomly assigned to one of two mutually exclusive mass-ratio feeding categories of house
mice (Mus musculus). The small category consisted of a prey mass ratio of 20-40% snake mass,
the large category, 41-60% snake mass. The effects of prey mass on the following factors were
examined: growth rates, time to begin prey-handling, capture position, prey-handling method,
lateralization side dominance (handedness), time to subdue, condition of prey at ingestion, time
to ingest, total feeding duration, and failure rates. Growth rates of P. guttatus were not
significantly different between the small and large mass-ratio feeding categories. Snake length,
mass, and girth were significantly correlated with one another. Results indicated that prey mass
significantly impacted various aspects of hatchling P. guttatus prey-handling behaviors. Time to
begin prey-handling, subdue, ingest, and total feeding duration were longer in the large category.
Snakes in both categories tended to capture and ingest prey more frequently by the anterior end
with the large category doing so more frequently than the small category. As prey mass
increased in both categories, so did the frequency of dominant prey-handling behavior. Smaller
prey were simply seized while larger prey were constricted. Handedness was not significantly
different between the two categories. As prey mass increased during the study, so did the
tendency for prey to be killed before ingestion as well as increased failure rates.
by
David A. Penning
A Thesis
presented in partial fulfillment
of the requirements for the degree of
Masters of Science
in the Department of Biology and Earth Science
February, 2012
© 2011
David Allen Penning
ALL RIGHTS RESERVED
by
David A. Penning
October, 2011
Thesis Committee Member
ACCEPTED:
Chair, Department ofBiology
UNIVERSITY OF CENTRAL MISSOURI
WARRENSBURG, MISSOURI
ACKNOWLEDGEMENTS
I would like to thank the Department of Biology and Earth Science at the University of
Central Missouri in Warrensburg, Missouri for partial research funding. The Institutional
Animal Care and Use Committee for approving the protocol (Protocol: 10-3212). I would
like to thank my Thesis Committee chair Dr. Cairns for his constant support and guidance.
He has been an invaluable resource throughout my graduate career and his help is greatly
appreciated. I would not have been able to get where I am today without his help. I would
also like to thank the rest of my committee, Dr. Wilson, Dr. Dean, and Ms. Mittelhauser for
their help throughout my research and graduate career. Their willingness to always keep
their doors open for me is something I will never forget.
I would like to acknowledge the Department of Biology and Earth Science’s faculty, staff,
and graduate students. I would like to especially thank Dr. Lankford and Mr. Metcalf for
their help and support through the IACUC review and approval process. I would also like to
thank Alvin Brass, Melissah Perkins, and Aaron Bossert for their constant support and
reviews of my work. They provided the much needed support system necessary to complete
this thesis. I would also like to thank Stephanie Tristani for her help during statistical review.
I would also like to give a special thanks to my family Debbie and Sarah Penning. I
could not have completed this project without their unwavering support. They are always
there for me without question and no matter the reason. I would also like to acknowledge my
late father, Patrick Penning. He is the reason that I do what I do and taught me to strive to be
the best I can be, to struggle as hard as I can for whatever I decided to believe in.
TABLE OF CONTENTS
Page
LIST OF TABLES………………………………………………………………………….viii
LIST OF FIGURES…………………………………………………………………………..ix
LIST OF PLATES…………………………………………………………………………..xiii
CHAPTER 1: INTRODUCTION……………………………………………………………..1
CHAPTER 2: MATERIALS AND METHODS………………………………………….......7
CHAPTER 3: RESULTS…………………………………………………………………….19
CHAPTER 4: DISCUSSION….…………………………………………………………….43
CHAPTER 5: CONCLUSIONS.……………………………………………………………82
CHAPTER 6: LITERATURE CITED…………………..…………………………………..84
APPENDICES
A.
COLLECTION DATA FOR ALL 18 P. guttatus..………………...……………86
B.
IACUC APPROVAL…………………………………………………………...104
C.
IACUC ADDENDUM………………………………………………………….118
LIST OF TABLES
TABLE
PAGE
1.1
Observations recorded during feeding trials with definitions of observations
and recordings as well as frequency schedules (presented in a similar
format as Mehta 2003)…………………………………………………………………...16
1.2
Data sheet used for collecting data………………………………..……………………..18
viii
LIST OF FIGURES
FIGURE
2.1
PAGE
The relationship between snake mass and total food mass consumed for the
small MR feeding category………………………………………………………………19
2.2
The relationship between snake mass and total food mass consumed for the
large MR feeding category…………………………………………………………….…20
2.3
Relationship between snake mass and total food consumed for both the small and large
MR feeding categories along with best fit lines and slope intercept…………………….21
2.4
The relationship between snake length and total food mass consumed for the
small MR feeding category…………………………………………………………...….22
2.5
The relationship between snake length and total food mass consumed for the
large MR feeding category……………………………………………………………….23
2.6
Relationship between snake length and total food consumed for both the small
and large MR feeding categories along with best fit lines and slope intercept………....24
2.7
The relationship between snake girth and total food mass consumed for the
small MR feeding category……………………………………………………………...25
2.8
The relationship between snake girth and total food mass consumed for the
large MR feeding category……………………………………………………………....26
2.9
Relationship between snake girth and total food consumed for both the small and
large MR feeding categories along with best fit lines and slope intercept……………...27
2.10
The Pearson correlation coefficient between snake mass and snake girth in the
small MR feeding category……………………………………………………………....28
ix
LIST OF FIGURES CONTINUED
FIGURE
2.11
PAGE
The Pearson correlation coefficient between snake mass and snake length in the
2.12
The Pearson correlation coefficient between snake girth and snake length in the
2.13
The Pearson correlation coefficient between snake mass and snake girth in the
large MR feeding category…………………………………………………………….…31
2.14
The Pearson correlation coefficient between snake mass and snake length in the
large MR feeding category……………………………………………………………….32
2.15
The Pearson correlation coefficient between snake girth and snake length in the
large MR feeding category………………………………………………………………33
2.16
Mean time ( x ±SD) to begin prey-handling for both MR feeding categories………….34
2.17
Total prey-capture event frequencies for both MR feeding categories………………….36
2.18
Total frequencies of prey-handling behaviors for both small and large MR feeding
categories………………………………………………………………………………...37
2.19
Lateralization side dominance frequencies for both small and large MR feeding
categories……………………………………………………………………………...…38
2.20
Relationship between weight (mass) of individual snakes and age (in days). Red
lines represent the large MR feeding category and blue lines represent the small
MR feeding category.…………………………………………………………………….44
x
FIGURE
PAGE
2.21
Age at sequential shedding periods for both MR feeding categories…………………...45
2.22
Average ( x ±SD) time period between shedding events ……………………………….46
2.23
Average % mass gain ( x ±SD) of mass per MR feeding category………………………47
2.24
Average % mass gain ( x ±SD) for each prey-handling method within each MR
feeding category ……………………………………………………………..………….48
2.25
Total prey capture events for all 22 weeks……………………………………………...50
2.26
Total prey capture frequencies for the first and second 11 weeks of trials……………. 52
2.27
Total frequencies of prey-handling behaviors for the small MR feeding
category…………………………………………………………………………………..55
2.28
Total frequencies of prey-handling behaviors for the large MR feeding
category…………………………………………………………………………………..56
2.29
Lateralization side dominance observations for constriction events…………………….58
2.30
Mean time ( x ±SD) to subdue prey for both MR feeding categories……………………59
2.31
Mean time ( x ±SD) to subdue prey for each prey-handling behavior (regardless of
category)…………………………………………………………………………………61
2.32
Mean time ( x ±SD) to subdue prey for each prey-handling behavior…………………62
2.33
Mean time ( x ±SD) to subdue prey using the simple seizing prey-handling
behavior………………………………………………………………………………….63
xi
FIGURE
PAGE
2.34
Mean time ( x ±SD) to subdue prey using the pinion prey-handling behavior…………..64
2.35
Mean time ( x ±SD) to subdue prey using the hairpin loop method……………………..66
2.36
Mean time ( x ±SD) to subdue prey using the constriction prey-handling method……..68
2.37
Total directional ingestion frequencies for both MR feeding categories……………..…69
2.38
Frequency of head-first ingestion of hairless and haired mice…………………………..70
2.39
Frequency of condition of prey at ingestion for the small mass ratio
feeding category…………………………………………………………………………73
2.40
Frequency of condition of prey at ingestion for the large mass ratio
feeding category…………………………………………………………………………74
2.41
Mean time ( x ±SD) to ingest prey for both MR feeding categories…………………….76
2.42
Mean time ( x ±SD) to ingest of directional ingestion for both MR feeding categories
(as one group)…………………………………………………………………….……..77
2.43
Mean time ( x ±SD) to ingest of directional ingestion for each MR feeding category…..78
2.44
Feeding trial failure frequencies for both the small and large MR feeding categories…..81
xii
LIST OF PLATES
PLATE
3.1
PAGE
Photographs of corn snakes taken during the 2010 breeding season.
(A) An adult male with typical background and saddle color patterns.
(B) Hatchlings pipping out of their eggs…………………………………………………..8
3.2
Photograph taken during the 2010 experimental trials. An overhead view of the
caging system for the 18 hatchlings……………………………………………………...9
xiii
CHAPTER 1
INTRODUCTION
Snakes are a group of reptiles within the order Squamata belonging to the suborder
Serpentes, which consists of more than 2,900 described species (Pough et al. 2004). Serpentes is
divided into 15 families, the largest of which, Colubridae includes more than 1,800 described
species, one of which is the corn snake, Pantherophis guttatus L. (Pough et al. 2004).
The corn snake is one of the most popular snakes in the pet industry (Love and Love
2005, Soderberg 2006). Much information on life history and care is available (Barnard et al.
1979, Bartlett and Bartlett 1996, Love and Love 2005, Soderberg 2006) but few studies have
been conducted on their behavior and growth. Many pet trade animals have extensive
information available about their natural history, health, and care but very little on biological
responses to their environment and behavior. Numerous studies have been conducted on feeding
response and prey-handling behaviors of snake feeding (Willard 1977, Jones 1988, Mori 1993;
96, Mehta 2003). However, there is limited information about prey-handling techniques of
ingestively naïve snakes in response to different prey masses as well as any ontogenetic shifts
and growth/shed rates through time. Feeding behaviors of corn snakes have yet to be described
in detail.
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1. Growth rates (mass, length, girth, growth associations, shed rates, and efficiencies)
Growth rates among snakes have been well studied (Kauffeld 1943, Henderson 1970,
Myer and Kowell 1973). Weight gain and length have been shown to be related to the amount of
food ingested (Barnard et al. 1979). Growth is more dependent on food consumed rather than
age and length is logarithmically related to body weight (Barnard et al. 1979). Frequency of
feeding and food mass can also affect growth in snakes (Myer and Kowell 1973). Baby corn
snakes can convert up to one-third of their food weight into added body mass (Love and Love
2005). As a snake consumes more food its total body mass increases. It is assumed that as a
snake ages, it will consume more prey. However, this assumption does not accurately relate the
size (mass) of a snake to its age because snakes consume prey at various rates that are impossible
to quantify unless studied from birth. The energy cost required to subdue larger prey as well as
average weight gain has not yet been empirically determined in the corn snake.
Shedding frequencies of snakes has not been studied in great detail. Few snake growth
studies have mentioned shed rates (Myer and Kowell 1973). Faster growing snakes shed more
frequently but this has not been studied alongside growth.
2. Prey-handling behaviors
A prey-handling behavior is defined as any action taken by a predator towards a prey
item. Sections 2.2-2.11 in chapter 1 expand on various aspects of snake prey-handling behaviors.
2.2. Time to begin prey-handling
Time to begin prey-handling is defined as the time at which the snake successfully
contacts with a prey item to the point at which the snake begins a prey-handling behavior
2
(personal definition). Many studies have recorded time aspects of prey-handling (Mori 1996,
Mehta 2003) but none has evaluated the time to begin prey-handling.
2.3. Capture position
Prey capture position is divided into three categories: 1) anterior (head and front
shoulders); 2) middle (abdomen and forelegs); 3) posterior (pelvic region, hind legs, and tail)
(Mehta 2003). Cooper (1981) suggested that (in a scincid lizard) attacks to the anterior end of
many large prey items would be favored due to the incapacitation of the prey’s major weapons,
which tend to be anteriorly placed. Diefenbach and Emslie (1971) stated that head movement by
the prey (mice) attracts the snake’s strike. In rodent-eating snakes, evolutionary pressures would
favor individuals using the most effective capture position.
2.4. Prey-handling method
Snakes employ different kinds of prey-handling behaviors for various types (de Queiroz
1984), sizes (Mehta 2003), and activity level (de Queiroz 1984) of prey. Simple seizing, pinion,
hairpin loop, and constriction are the four prey-handling behaviors of non-venomous snakes
(Mehta 2003). Simple seizing is defined as grasping the prey with the jaws without using any
other portion of the body (Mori 1993). Pinion of prey is defined as pressing the prey against a
surface using any portion of the snake’s body (Mori 1993). Hairpin loop is defined as squeezing
the prey between non-overlapping (partially encircling) portions of the snake’s body (Mori 1993).
Constriction is defined as a behavior pattern in which prey is immobilized by pressure exerted
from two or more points on the snake’s body (Greene and Burghardt 1978).
Constriction is further divided into three categories: 1) coils with ventral surface facing
towards the head of the snake; 2) coils with dorsal surface facing towards the head of the snake;
3
3) irregular and possibly overlapping coils with no consistent surface facing the head of the
snake (Willard 1977). Specific portions of constriction were defined in greater detail: 1) loop:
one fully encircling portion of the snake’s body around the prey (Greene and Burghardt 1978); 2)
non-overlapping loop: squeezing prey between non-overlapping portions of the body (Mori 1993)
(Mehta 2003) referred to this term as a hairpin loop); and 3) coil: the total of all loops (Greene
and Burghardt 1978).
2.5. Lateralization side dominance (Handedness)
Side dominance has been observed in many organisms (Heinrich and Klaassen 1985).
Lateralization side dominance is defined as a snake’s side coil tendency ("Episode #42
Lateralization Side Dominance") and it has been noted by very few snake researchers (Willard
1977, Heinrich and Klaassen 1985). Willard (1977) stated that no species showed a preference
for either side dominance and also observed 37 constrictions from two P. guttatus and noted
that the snakes showed a tendency toward right sidedness (handedness). Lateralization side
dominance is differentiated from constriction methods in that ventral and dorsal curling are not
the factors determining lateralization side dominance (handedness) (Willard 1977). The lateral
side actually contacting the prey during constriction is considered to be the right or left
handedness, not the curling direction (or rotation) of the constriction.
2.6. Time to subdue prey
Time to subdue prey is the time from the snake successfully engaging prey to the start of
swallowing (Mehta 2003). The start of swallowing is defined as the first sign of unilateral
walking of the snake’s jaw along the body of the prey (on the successful swallowing attempt)
4
(personal definition). On occasions when snakes failed swallowing, they regurgitated the prey
and started swallowing again.
2.7. Direction of Ingestion
Head-first ingestion is a common strategy in vertebrates (Ashton 2002). In a study on the
broadhead skink, Eumeces laticeps (Schneider), Cooper (1981) suggested that it is physically
less demanding to swallow prey head-first which would also allow for easier swallowing of the
larger rear. Energetic expenditure may also be affected by the direction of ingestion (Diefenbach
and Emslie 1971). Preference for head-first ingestion has also been supported in snake studies
(Diefenbach and Emslie 1971, Klein and Loop 1975, Ashton 2002, Mehta 2003). The frequency
of head-first ingestion has been observed for both adult (Mori 1996) and neonatal snakes (Mehta
2003). Direction of hair is thought to be the primary tactile cue for head-first ingestion but use
of chemical and visual cues have also been supported (Diefenbach and Emslie 1971). Prey may
be swallowed from the posterior position (tail-first) but this is less frequent and requires more
time (Diefenbach and Emslie 1971). Klein and Loop (1975) suggested that the tendency to
ingest large prey head-first is inherited.
2.8. Condition of prey at ingestion
There are only two options for condition of prey at ingestion: they are either swallowed
alive or dead. Prey is considered alive if there is any movement shown by the prey at the start of
swallowing. Live prey die of suffocation while being swallowed by a snake so the condition of
prey is evaluated at the very beginning of ingestion.
5
2.9. Time to ingest
Time to ingest prey is the time from the start of swallowing to the point at which the
snake begins to push the prey item towards its mid-body (Mehta 2003). For this study, a further
detailed definition was used; time to ingest was considered the time from the first unilateral
walking motion of the snake’s jaw on the prey item (during the successful swallowing attempt)
to the point at which the widest girth of the prey item was at the 5th saddle pattern on the snake’s
body. This was considered the completion of swallowing because it allowed the snake to
successfully defend itself.
2.10. Total feeding duration
Total feeding duration is the time from prey capture to the end of prey ingestion (Mehta
2003). For this study, a further detailed definition was used. Total feeding duration was
considered the time at which the prey entered the feeding arena to the completion of swallowing.
2.11. Failure rates
Failing to capture prey is a common occurrence. Natural environments offer fewer
chances to recapture a prey item after the first failed attempt because prey can flee great
distances. Failure rates in captive feeding trials occur but are usually a result of the prey
successfully avoiding capture until the snake exhausts all attempts at capture. Failure rates of
captive feeding trials have not been addressed in any previous study.
6
CHAPTER 2
MATERIALS AND METHODS
Study Organism
The rat snake species considered in this study is shown in Plate 3.1. The caging system is
shown in Plate 3.2.
Pantherophis guttatus (Linnaeus 1766)
Pantherophis guttatus was described by Linnaeus (1766) as Elaphe guttata. This species
is easily recognized by its long and slender body which is covered with a brown, red, or grey
saddle pattern outlined with black with one or two rows of side blotches. The background color
can vary from grey to orange. The venter is a black and cream or pink color with a checker
board pattern. Dorsal scales are smooth, sometimes weakly keeled and the anal plate is divided.
Juvenile P. guttatus are generally greyer in color than adults. The pupil is round with a dark
stripe extending from the eye to the neck. P. guttatus are distributed throughout the southeastern
portions of the United States. They are often found in woodland and grassy areas but are also
commonly found around farms. The name “corn snake” is thought to have come from
populations inhabiting barns and corn fields. P. guttatus also have a venter that looks similar to
the patter of Indian corn.
7
A
B
Plate 3.1 Photographs of corn snakes taken during the 2010 breeding season. (A) An adult male
with typical background and saddle color patterns. (B) Hatchlings pipping out of their eggs.
8
Plate 3.2 Photograph taken during the 2010 experimental trials. An overhead view of the caging
system for the 18 hatchlings.
9
I.
Date and time of project
The first clutch of snakes began hatching on 8 June 2010 and all snakes hatched by 15
June 2010. Cages were setup in Animal Room VI in the basement of the W.C. Morris building
on the campus of the University of Central Missouri on 22 June 2010. On 25 June 2010, 18
snakes were placed in the cages. Feeding trials began on the Tuesday after the snakes first shed
(29 June 2010) and continued until 1 December 2010. Feeding trials were due to run until 14
December 2010 but a food supply event stopped the study two weeks early (see “IV. Food
Preparation” for details).
II.
Breeding, hatching, and randomization
The 18 snakes used in this study came from my personal collection. Parents of the
offspring were originally obtained from Miles of Exotics in Kansas City, Missouri. All snakes
shared the same father and therefore were 50% genetically related. The father was a
phenotypically normal corn snake that was double heterozygous for motley and amelanistic
morphological traits (known as a “morph”). One mother was an amelanistic heterozygous for
motley while the other mother was amelanistic and anerythristic A. All hatchling snakes used in
the study were phenotypically normal but carried various non-expressed alleles. Based on the
information currently available, none of the known genetic traits have an effect on snake
behavior.
Breeding adults began brumation (winter shutdown for the purposes of captive breeding)
on 4 December 2010. Average brumation temperature was 15.5°C. The male and females were
caged together on 10 February 2010. Sub-surface heating units were turned on 20 February 2010.
In their natural environment, corn snakes breed from March to May, lay eggs in May through
10
July, and eggs hatch from July through September (Behler and King 1998). My collection’s
breeding season began a few weeks earlier due to previous annual breeding of my adult breeding
stock. This was done to get a close approximation of egg laying and hatching.
All snake eggs were incubated in the same type of incubator (Little Giant® Still Air
Incubator) with the same average temperature (28°C) and humidity (≤80%). Humidity and
temperature were monitored daily and all incubators were in the same room and exposed to the
same temperature fluctuations. Snakes hatched and were placed in individual cages and labeled
with their clutch information, mass (g), length (cm), and girth (cm) on their lids. Total snake
length was measured using Snakemeasurer (see measuring instructions in “VI. Recording and
Collecting Data” for further detail). Snakes were given a small water dish and a thin layer of
aspen bedding in their cages. Water was available at all times (see “III. Care and Maintenance”
for details). Hatchlings were then checked once per week for their first shed. Checking for
sheds once a week allowed more snakes to enter the experiment at one time rather than putting
each one in to the experiment on the exact day of their first shed. Checking once a week was a
sufficiently narrow window so that there were no differences between individual snake’s energy
levels from lack of food consumption when entering the experiment. The feeding trials began
the following scheduled feeding day upon the discovery of each snake’s first shed. The order in
which the snakes were placed into each category was determined by a random number generator.
III.
Care and maintenance
The cage design was determined by what would work best for filming, space efficiency,
cost, and maintenance for a sample size of 18 snakes. Each corn snake was held individually in a
cage internally measuring 27.9×27.9×15.2 cm (11×11×6 inches). Cages measuring 49×34×30cm
11
(19×13×11 inches) were used for yearling corn snakes by Barnard et al. (1979) but a cage of this
size is not necessary if the snake is kept under ideal conditions. Snakes do not necessarily
require large cages (Mattison 2007). If snakes that hide during most of the day are provided with
all of their needs they will be content to live in cages that measure less than their body length
(Mattison 2007). Corn snakes are great climbers and can be arboreal in nature but are mostly
found on the ground (Conant and Collins 1992, Mattison 2007). Because these snakes will not
need to escape predators or search for food, height in caging is not necessary. In addition, other
studies have used cages of similar size to house hatchling snakes (Myer and Kowell 1973, Mori
1993; 1996, Mehta 2003).
Smaller cages drastically cut costs but still provided adequate space for a hatchling to
juvenile corn snakes. Small cages are easier to heat and are more economical to build than larger
ones (Soderberg 2006). A sliding, clear piece of glass was used for the lid so that filming could
be done from overhead without disturbing the snake or exposing it to other individuals. The lid
slid into a groove ca. 6mm from the top of the enclosure. Multiple 5mm holes were drilled into
the backs and fronts of the cages for proper air exchange. This allowed proper ventilation
without exposing each snake to the visual cues of other snakes (Plate 3.2).
Aspen shavings were used as substrate because of their lack of dust and absorbent
capability, which prevented bacterial and fungal growth in the bedding. Aspen shavings placed
in each enclosure ca. 1.5cm in depth allowed snakes to burrow in times of stress. Water was
available at all times in SOLO® 16oz plastic cups cut to fit each cage. The internal color of the
cup was white which allowed for identification of ectoprasites found in the water bowl
(Soderberg 2006). Heat for the snakes was provided by a liquid oil space heater (Delonghi 1500
watt, TYP 5307) circulated by a small fan (Zippi Vornado Air Circulation System) and set at
12
28.3°C (83.0°F); the ambient temperature averaged 27.9°C (82.2°F). Heating the entire room is
a common practice among many snake keepers (Soderberg 2006). Many experiments frequently
keep snakes at or slightly above room temperature without individual heat sources (Smith and
Watson 1972, Mori 1993, 1996, Mehta 2003,). Each cage was spot cleaned daily and bedding
was changed pro re nata. No mites or parasites of any kind were observed during the
experiment.
IV.
Food preparation
House mice (Mus musculus L.) were the only food given to snakes in the experiment.
The mice were brought in from an outside source and did not remain at the University of Central
Missouri, Warrensburg for more than 12 hours. Mice were kept in colonies of 1:3 (one male and
three females) and 1:2 (one male and two females) depending on the cage size in which they
were housed. Mice were kept on shredded paper, cleaned twice weekly, and food and water
were available at all times. The mice were fed Purina LabDiet 5001 Rodent Diet, a commonly
used whole food system for mice production which was used by several local backup suppliers
of mice (Country Pets and Ponds, Pet Lover’s Lane, and Miles of Exotics). Mice were handled
as little as possible and raised in a facility that also had a small colony of soft-furred rats
(Praomys sp. Thomas) and Norway rats (Rattus norvegicus Berkenhout). Different rodent
species never had direct contact with one another.
Mice were raised in a 3.04×3.04 m (10×10 ft) insulated and ventilated building. Heat
was supplied from two DeLonghi 1500-Watt Utility Heaters©. The primary heater was set to
produce an ambient temperature of ca. 23.9°C (75.0°F) while the second heater was set slightly
lower and was used for backup purposes only. An electrical failure of the building happened
13
overnight on 2 December 2010. The adult mice survived but the event proved to be fatal for all
developing litters of mice. A backup supply of mice could not be acquired in time to continue
the study for the last two weeks of feeding trials. The trials were cut short at 22 weeks instead of
the full 24 week schedule.
V.
Feeding trials
Each snake was put into a feeding schedule of one meal per week which is a sufficient
feeding frequency (Love and Love 2005). Snakes were fed on Tuesday and Wednesday
depending on their feeding category. The two feeding categories were mutually exclusive and
were labeled as small and large. The small feeding category had a prey mass-ratio of 20-40% of
the snake’s mass while the large category had a ratio of 41-60% of the snake’s mass. Snakes
were weighed using an AWS high capacity precision pocket scale (SC-2kg) the day prior to each
feeding trial and prey mass range was calculated for them. A prey item within the snake’s range
was chosen ca. one hour before trials began (using an AWS high capacity precision pocket scale,
SC-2kg). Mice were transported to the University in containers in which all individuals of
similar mass were grouped together. Mice were then chosen at random and weighed (using an
AWS high capacity precision pocket scale, SC-2kg) to match the appropriate snake.
Each feeding trial for each snake was filmed from start to finish using a SONY Cybershot (DSC-T70) 8.1 megapixel camera/video recorder. Each trial began by sliding the cage lid
open and dropping the mouse ca. 10 cm from the head of the snake and then the lid was closed.
Filming took place from just before the lid was opened to completion of the feeding trial. The
camera was placed directly on the glass and I stepped away to disturb the process as little as
possible. Observations were recorded as the trial progressed. Filming was done as a backup in
14
the event that observations were missed during the original trial. A secondary timer was also
used in case of video malfunction. Snakes that failed to eat for four weeks in a row were
removed from the study. A failed feeding trial was considered a period of 40 minutes at any
point of the feeding trial in which the snake did not engage the prey. Mice that were not engaged
were removed from the cage and returned to the breeding facility.
15
VI.
Recording and collecting data
Table 1.1 Observations recorded during feeding trials with definitions of observations and
recordings as well as frequency schedules (presented in a similar format as Mehta 2003).
Observations and Behaviors
Description
Mass-ratio feeding category
Small (20-40%MR)
Large (41-60%MR)
Mass (weekly) (grams)
Length (monthly) (cm)
Girth (monthly) (cm)
Noted pro re nata
Point at which prey enters cage to the
point at which the snake’s mouth contacts
prey for final capture
Anterior (head and shoulders)
Mid section (abdomen and front legs)
Posterior (Pelvic region and back)
Simple seizing (grasping prey with
mouth)
Pinion (Using body to press prey against
surface)
Hairpin loop (Squeezing prey with a nonoverlapping portion of body)-“U” shape
Constriction (using loops of body)
Right or left sided coils
Dead
Alive
Anterior
Posterior
Time from prey successfully engaged to
prey subdued
Time from the start of swallowing to
completion of swallowing
Time to begin prey-handling to the
completion of swallowing
Snake size
Shed cycle
Time to begin prey-handling
Capture position of prey
(part of prey first grasped by feeding attempt)
Prey-handling method
Lateralization side dominance (handedness)
Prey condition before ingestion
Swallowing position
Time to subdue
Time to ingest
Feeding duration
Snake mass was measured on a digital scale (AWS sc-2kg) to 0.1g. Although previous studies
measured snake length using snout to vent length (Mori 1996) I used snout to tail length as it is a
more complete measurement of growth (Franz 1977). Furthermore, small snakes are difficult to
16
measure and can be easily injured by trying to manually measure a snout to vent length. Snakes
were placed on a piece of 0.5 cm graph paper and photographed directly overhead approximately
100 cm above the snake. Pictures were then entered into the SnakeMeasurer© program to get
lengths using the 0.5 cm paper as the measurement reference. With the 0.5 cm graph width as
the reference, a line was then drawn down the mid-line of the snake. The mid-line was traced
through the saddle patterns on the dorsal portion of the snake. This allowed for an accurate
measure of snake length regardless of the orientation of the snake. Snake length was recorded to
the 0.1cm. Girth (in cm) was measured using a flexible measuring tape and wrapped around the
snake at the half way point of the body. All experimental data are available in Appendix A.
University Animal Care and Use Committee (IACUC) documentation is available in Appendix B
and the IACUC addendum is in Appendix C.
VII.
Statistical Analysis
All statistical analysis was conducted on either Microsoft Office Excel 2007 or Minitab
14. Averages, standard deviations, binomials, chi-squares, correlations, and simple linear
regressions were run on Microsoft Office Excel 2007. General Linear Models, Mann Whitney
tests, and 2 sample t-tests were performed on Minitab 14. Individual variables with associated
tests can be found in Chapter 3.
17
18
#
#
#
#
Monthly
Measurements
Week
Week
Week
Week
Week#
Week#
Week#
Week#
MR category-
Snake #
Straight Line Length
Time to Subdue
Prey
Girth
Time to
Ingest
Total Feeding
Duration
Mass of Snake
Mass of Prey Time to Begin
(day before feeding)
Offered
Prey-handling
Preyhandling
Method
SS,P,HL,C
Week#
Week#
Week#
Week#
Additional Notes:
Capture
Position
Anterior
Mid
Posterior
Handedness
Condition of
Prey at
Ingestion
Dead or Alive
Swallow
Position
Anterior or
Posterior
Table 1.2 Data sheet used for collecting data.
CHAPTER 3
RESULTS
1. Snake growth (mass, length, girth, growth associations, shed rates, and efficiencies)
A. Mass
Snake mass is significantly related to the amount of food consumed in the small MR
feeding category (p<0.05, r²=0.974) and expressed by the following simple linear regression
model: Snake mass = 3.85 + 0.419 (total food consumed) (Fig 2.1).
60
Snake mass = 3.85 + 0.419(total food consumed)
R2 = 0.974
Snake Mass (g)
50
40
30
20
10
0
0
20
40
60
80
100
120
Food Consumed (g)
Fig 2.1 The relationship between snake mass and total food mass consumed for the small MR
feeding category.
19
Snake mass is significantly related to the amount of food consumed in the large MR
model: Snake mass = 4.84 + 0.395 (total food consumed) (Fig 2.2).
Snake mass = 4.84 + 0.395 (total food consumed)
R² = 0.949
80
70
Snake Mass(g)
60
50
40
30
20
10
0
0
20
40
60
80
100
120
140
160
180
Food Consumed(g)
Fig 2.2 The relationship between snake mass and total food mass consumed for the large MR
feeding category.
20
The intercepts of the regression models (Fig 2.1 and Fig 2.2) are not significantly
different (General Linear Model, p>0.05) (Fig 2.3).
The slopes of the regression models (Fig 2.1 and Fig 2.2) are not significantly different
(General Linear Model, p>0.05) (Fig 2.3).
70
Weight of snake (g)
60
50
Small MR feeding category
40
Large MR feeding category
30
20
Linear (Small MR feeding
category)
10
Linear (Large MR feeding
category)
0
0
50
100
150
Weight of food consumed (g)
Fig 2.3 Relationship between snake mass and total food consumed for both the small and large
MR feeding categories along with best fit lines and slope intercept.
21
B. Length
Snake length is significantly related to the amount of food consumed in the small MR
model: Snake length = 33.3 + 0.263 (total food consumed) (Fig 2.4).
Snake length = 33.3 + 0.263 (total food ingested)
R² = 0.795
65.0
60.0
Length (cm)
55.0
50.0
45.0
40.0
35.0
30.0
25.0
0
20
40
60
80
100
120
Food Consumed (g)
Fig 2.4 The relationship between snake length and total food mass consumed for the small MR
feeding category.
22
Snake length is significantly related to the amount of food consumed in the large MR
model: Snake length = 32.7 + 0.244(total food consumed) (Fig 2.5).
Snake length= 32.7 + 0.244 (total food ingested)
R² = 0.810
70.0
65.0
Length (cm)
60.0
55.0
50.0
45.0
40.0
35.0
30.0
25.0
0
20
40
60
80
100
120
140
160
Food Consumed (g)
Fig 2.5 The relationship between snake length and total food mass consumed for the large MR
feeding category.
23
70.0
65.0
60.0
Length (cm)
55.0
50.0
45.0
category)
40.0
35.0
category)
30.0
25.0
0
50
100
150
Food consumed (g)
Fig 2.6 Relationship between snake length and total food consumed for both the small and large
24
C. Girth
Snake girth is significantly related to the amount of food consumed in the small MR
model: Snake girth = 2.23 + 0.0180(total food consumed) (Fig 2.7).
Snake girth = 2.23 + 0.0180(total food consumed)
R² = 0.807
4.5
4.0
Girth (cm)
3.5
3.0
2.5
2.0
1.5
0
20
40
60
80
100
120
Food consumed (g)
Fig 2.7 The relationship between snake girth and total food mass consumed for the small MR
feeding category.
25
Snake girth is significantly related to the amount of food consumed in the large MR
model: Snake girth = 2.21 + 0.0183(total food consumed) (Fig 2.8).
Snake girth = 2.21 + 0.0183(total food consumed)
R² = 0.839
5.0
4.5
Girth (cm)
4.0
3.5
3.0
2.5
2.0
1.5
0
20
40
60
80
100
120
140
160
Food consumed (g)
Fig 2.8 The relationship between snake girth and total food mass consumed for the large MR
feeding category.
26
5.0
4.5
Girth (cm)
4.0
3.5
3.0
2.5
category)
2.0
category)
1.5
0
50
100
150
Food consumed(g)
Fig 2.9 Relationship between snake girth and total food consumed for both the small and large
27
D. Growth associations
Various aspects of growth were correlated with one another. Figure 2.10, 11, 12, 13, 14,
and 15 are all correlations with best fit lines.
60
Mass (g)
50
R = 0.912
p<0.05
40
30
20
10
0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
Girth (cm)
Fig 2.10 The Pearson correlation coefficient between snake mass and snake girth in the small
MR feeding category.
28
70
60
Mass (g)
50
R = 0.881
p<0.05
40
30
20
10
0
20.0
25.0
30.0
35.0
40.0
45.0
50.0
55.0
60.0
65.0
70.0
Length (cm)
Fig 2.11 The Pearson correlation coefficient between snake mass and snake length in the small
29
5.0
4.5
R = 0.853
p<0.05
Girth (cm)
4.0
3.5
3.0
2.5
2.0
1.5
25.0
30.0
35.0
40.0
45.0
50.0
55.0
60.0
65.0
70.0
Length (cm)
Fig 2.12 The Pearson correlation coefficient between snake girth and snake length in the small
30
70
60
Mass (g)
50
R = 0.934
p<0.05
40
30
20
10
0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
Girth (cm)
Fig 2.13 The Pearson correlation coefficient between snake mass and snake girth in the large
31
70
60
R = 0.889
p<0.05
Mass (g)
50
40
30
20
10
0
25.0
30.0
35.0
40.0
45.0
50.0
55.0
60.0
65.0
70.0
75.0
Length (cm)
Fig 2.14 The Pearson correlation coefficient between snake mass and snake length in the large
32
5.0
4.5
R = 0.922
p<0.05
Girth (cm)
4.0
3.5
3.0
2.5
2.0
1.5
25.0
30.0
35.0
40.0
45.0
50.0
55.0
60.0
65.0
70.0
Length (cm)
Fig 2.15 The Pearson correlation coefficient between snake girth and snake length in the large
33
2. Time to begin prey handling
1st week (ingestively naïve)
Time to begin prey-handling of ingestively naïve snakes is not significantly different
between the small and large mass ratio feeding categories (Mann Whitney test, W = 60, n1 = n2 =
8, p>0.05). The mean time ( x ±SD) to begin prey-handling for the small mass ratio feeding
category is 00:04:35±00:08:36 and the large mass ratio feeding category is 00:02:05±00:01:08.
Entire study (22 weeks)
Time to begin prey-handling is significantly different between the small and large mass
ratio feeding categories for the entire study (Mann Whitney test, W = 16497.5, n1 = 158, n2 = 89,
p<0.05). The mean time ( x ±SD) to begin prey-handling for the small mass ratio feeding
category is 00:01:38±00:04:41 and the large mass ratio feeding category is 00:03:14±00:05:57
(Fig 2.16).
0:10:05
0:08:38
0:07:12
0:05:46
Time
0:04:19
0:02:53
0:01:26
0:00:00
Fig 2.16 Mean time ( x ±SD) to begin prey-handling for both MR feeding categories.
34
3. Capture position
The frequency of anteriorly captured prey of ingestively naïve snakes is not significantly
greater than the frequency of prey captured by the mid-body and posterior (lumped together as
“other”) in the small and large mass ratio feeding category (Binomial Goodness of Fit test,
p>0.05). Prey were captured anteriorly 62.5%, the mid-body 37.5%, and posteriorly 0% in the
small mass ratio feeding category. Prey were captures anteriorly 75%, the mid-body 25%, and
posteriorly 0%.
The observed frequencies among the three capture positions for the small mass ratio
feeding category differed significantly from the expected frequency of 1/3:1/3:1/3 for the entire
study (X² Goodness of Fit, X2 = 50.0, df = 2, p<0.05). The summation of capture positions
frequencies: 59.49% anterior attacks, 24.05% being attacks to the mid-body, and 16.45%
posterior attacks (Fig 2.17).
The observed frequencies among the three capture positions for the large mass ratio
feeding category differed significantly from the expected frequency of 1/3:1/3:1/3 for the entire
study (X² Goodness of Fit, X2 = 52.8, df = 2, p<0.05) The summation of capture position
frequencies: 69.66% anterior attacks, 14.60% being attacks to the mid-body, and 15.73%
posterior attacks (Fig 2.17).
35
100
90
80
Frequency (%)
70
60
Anterior
50
Mid-body
40
Posterior
30
20
10
0
Fig 2.17 Total prey-capture event frequencies for both MR feeding categories.
4. Prey-handling method
The frequency of simply seized prey of ingestively naïve snakes is not significantly
greater than the frequency of prey-handled using pinion, hairpin loop, and constriction (all three
lumped together as “other”) in the small and large mass ratio feeding category (Binomial
Goodness of Fit test, p>0.05). Prey were simply seized anteriorly 75%, pinioned 0%, hairpin
looped 0%, and constriction 25% in the small mass ratio feeding category. Prey were simply
seized anteriorly 75%, pinioned 12.5%, hairpin looped 0%, and constriction 12.5% in the small
mass ratio feeding category.
36
The frequency of prey-handling methods of snakes in the small mass ratio feeding
category is significantly different than the expected frequency of 1/4:1/4:1/4:1/4 for the entire
study (X² Goodness of Fit test, X2 = 159.2, df = 3, p<0.05). The summation of observed prey
handling method frequencies: 63.29% constriction, 31.64% simple seizing, and 2.53% for both
pinion and hairpin loop (Fig 2.18)
The frequency of prey-handling methods of snakes in the large mass ratio feeding
category is significantly different than the expected frequency of 1/4:1/4:1/4:1/4 for the entire
study (X² Goodness of Fit test, X2 = 123.6, df = 3, p<0.05). The summation of observed prey
handling method frequencies: 74.15% constriction, 22.47% simple seizing, 2.24% pinion, and
1.12% hairpin loop (Fig 2.18)
100
90
80
Frequency (%)
70
60
Simple Seizing
50
Pinion
Hairpin Loop
40
Constriction
30
20
10
0
Fig 2.18 Total frequencies of prey-handling behaviors for both small and large MR feeding
categories.
37
5. Handedness
The frequency of right lateralization side dominance is not significantly greater than the
frequency of left lateralization side dominance in the small mass ratio feeding category for the
entire study (Binomial Goodness of Fit test, p>0.05). Lateralization side dominance frequencies:
51.02% right handed and 48.97% left handed (Fig 2.19).
The frequency of left lateralization side dominance is not significantly greater than the
frequency right lateralization side dominance in the large mass ratio feeding category for the
entire study (Binomial Goodness of Fit test, p>0.05). Lateralization side dominance frequencies:
53.03% left handed and 46.96% right handed (Fig 2.19).
100
90
80
Frequency (%)
70
60
Right Handedness
50
Left Handedness
40
30
20
10
0
Fig 2.19 Lateralization side dominance frequencies for both small and large MR feeding
categories.
38
6. Time to subdue prey
Time to subdue prey of ingestively naïve snakes is not significantly different between the
small and large mass ratio feeding categories (Mann Whitney test, W = 57, n1 = n2 = 8, p>0.05).
The mean time ( x ±SD) to subdue prey for the small mass ratio feeding category is
00:05:52±00:14:01 and the large mass ratio feeding category is 00:05:15±00:10:16.
Time to subdue prey is not significantly different between the small and large mass ratio
feeding categories for the entire study (Mann Whitney test, W = 18612.0, n1 = 158, n2 = 89,
p>0.05). The mean time ( x ±SD) to subdue prey for the small mass ratio feeding category is
7. Direction of ingestion
The frequency of anteriorly ingested prey of ingestively naïve snakes is significantly
greater than the frequency of posteriorly ingested prey in the small mass ratio feeding category
(Binomial Goodness of Fit test, p<0.05). Prey ingested anteriorly occurred 87.5% of the trials
and prey was ingested posteriorly 12.5% of trials.
The frequency of anteriorly ingested prey of ingestively naïve snakes is significantly
greater than the frequency of posteriorly ingested prey in the large mass ratio feeding category
(Binomial Goodness of Fit test, p<0.05). Prey ingested anteriorly occurred 87.5% of the trials
and prey was ingested posteriorly 12.5% of trials.
39
The frequency of anteriorly ingested prey is significantly greater than the frequency of
posteriorly ingested prey in the small mass ratio feeding category for the entire study (Binomial
Goodness of Fit test, p<0.05). Prey ingested anteriorly occurred 88.60% of the trials and prey
was ingested posteriorly 11.39% of trials.
The frequency of anteriorly ingested prey is significantly greater than the frequency of
posteriorly ingested prey in the large mass ratio feeding category for the entire study (Binomial
Goodness of Fit test, p<0.05). Prey ingested anteriorly occurred 95.50% of the trials and prey
was ingested posteriorly 4.49% of trials.
8. Condition of prey at ingestion
The frequency of alive prey at ingestion of ingestively naïve snakes is significantly
greater than the frequency of dead prey at ingestion for the small mass ratio feeding category
(Binomial Goodness of Fit test, p<0.05). Prey ingested alive occurred 100% of the trials.
The frequency of alive prey at ingestion of ingestively naïve snakes is significantly
greater than the frequency of dead prey at ingestion for the large mass ratio feeding category
(Binomial Goodness of Fit test, p<0.05). Prey ingested alive occurred 100% of the trials.
The frequency of alive prey at ingestion is significantly greater than the frequency of
dead prey at ingestion for the small mass ratio feeding category for the entire study (Binomial
Test, p<0.05). Prey ingested alive occurred 56.96% of the trials and prey was killed prior to
ingestion 43.03% of the time.
40
The frequency of alive prey at ingestion is significantly greater than the frequency of
dead prey at ingestion for the large mass ratio feeding category for the entire study (Binomial
Goodness of Fit test, p<0.05). Prey ingested alive occurred 62.92% of the trials and prey was
killed prior to ingestion 37.07% of trials.
8.b. Condition of prey at ingestion frequencies concept
The average mass of prey eaten during weeks 13,14, and 15 in the small MR feeding
category was not significantly different from the average mass of prey eaten during weeks 6, 7,
and 8 in the large MR feeding category (2 sample t-test, t = -1.30, df = 29, p>0.05).
9. Time to ingest
Time to ingest prey of ingestively naïve snakes is significantly different between the
small and large mass ratio feeding categories (Mann Whitney test, W = 36.0, n1 = n2 = 8, p<0.05).
The mean time ( x ±SD) to ingest prey for the small mass ratio feeding category is
Time to ingest prey is significantly different between the small and large mass ratio
p<0.05). The mean time ( x ±SD) to ingest prey for the small mass ratio feeding category is
41
Time to ingest prey was not significantly different between prey swallowed head-first and
prey swallowed tail-first in and between the small and large MR feeding categories for the entire
study (2 sample t-test, t = 1.71, df = 35, p>0.05).
10. Total feeding duration
Total feeding duration of ingestively naïve snakes is not significantly different between
the small and large mass ratio feeding categories (Mann Whitney test, W = 49, n1 = n2 = 8,
p>0.05). The mean ( x ±SD) time of total feeding duration for the small mass ratio category is
Total feeding duration is significantly different between the small and large mass ratio
p<0.05). The mean time ( x ±SD) of total feeding duration for the small mass ratio category is
42
CHAPTER 4
DISCUSSION
1. Snake growth (mass, length, girth, shed rates, and efficiencies)
In both the small and large MR feeding categories, growth in mass, length, and girth
was significantly related to total food consumed (see results 1A, 1B, and 1C). There was no
significant difference between the regression slopes of the small and large MR feeding categories
for all 3 growth forms. This statistically supports the concept that food ingested (regardless of
how it is ingested) will result in similar growth (Fig 2.5, 2.8, 2.11).
Mass, length, and girth
gained by the snakes in this study depended upon the total amount of prey ingested. This
supports the idea that snake mass is not dependent upon age alone. These findings agree with
Barnard et al. (1979) in that snake mass is not an accurate estimation of snake age. These
findings also support Barnard et al. (1979) in that variation (in mass) among individuals
increased as amount of food increased and is presented in a similar format in (Fig 2.20). Snake
size (mass) should not be used as an estimator of age beyond reproductive status (which
generally accompanies a minimum age bracket).
43
80
70
60
Mass (g)
50
40
30
20
10
0
0
7 14 21 28 35 42 49 56 63 70 77 84 91 98 105 112 119 126 133 140 147
Age (in days)
Fig 2.20 Relationship between weight (mass) of individual snakes and age (in days). Red lines
represent the large MR feeding category and blue lines represent the small MR feeding category.
Barnard et al. (1979) reported a correlation coefficient of 0.996 for the association
between snake length and body weight (mass) in the corn snake. The correlation coefficient (in
this study) for the same associations in the small MR feeding category is 0.881 and 0.934 for the
large MR feeding category (Results 1.D.). Although the correlation coefficients in this study
were smaller than the findings in Barnard et al. (1979) they still show the same support with the
similar associations. A longer study is needed to specifically examine the correlation coefficient
from Barnard et al. (1979) as theirs was a much longer study than the 22 week length of this
experiment.
In both the small and large MR feeding categories the correlation coefficients were
similar for mass and length, mass and girth, and length and girth (Results 1.D.). These suggest
44
that there is a close association between the two MR feeding categories. Length, girth, and mass
all covary with one another in a similar manner.
Shedding frequencies of snakes have not been studied in great detail. Faster growing
snakes shed more frequently but this has not been repetitively studied alongside growth data.
Corn snake shed cycles from this experiment are presented in the same format as that of Myer
and Kowell (1973) (Fig 2.21). The average time between sheds are presented in Figure 2.22.
There is no noticeable biological trend that can be inferred from these data because the averages
are not consistently longer or shorter periods of time in one category and the standard deviations
overlap.
180
160
140
Age (Days)
120
100
80
60
40
20
0
0
1
2
3
4
5
6
7
Shedding Period
Fig 2.21 Age at sequential shedding periods for both MR feeding categories.
45
60.0
50.0
Days
40.0
30.0
20.0
10.0
0.0
1
2
3
4
Shed Events
5
6
Fig 2.22 Average ( x ±SD) time period between shedding events.
Corn snakes had a variable % mass gain [(current pre-feeding snake mass - previous prefeeding snake mass) / (prey mass from previous week)*100] in body weight. Love and Love
(2005) stated that baby corn snakes can convert up to 33% of their food (prey) weight into body
mass. Corn snakes in this study had a percent mass gain range of -15% to 93% mass gain. The
average percent gain for the small MR feeding category was 40±19.3%. The average percent
gain for the large MR feeding category was 45±22.4% (Fig 2.23). The averages suggest that it is
more advantageous to eat larger prey (if the goal is mass gained) but when accompanied by the
standard deviations there is no discernable difference between the % mass gains of the two MR
feeding categories. This observation is a much more variable number than the percentage
presented by Love and Love (2005). There may be varying metabolic factors impacting mass
gain that were not addressed in this study. A mass gain ratio does not appear to be a reliable
measure of energetic gain.
46
100
90
% mass gain (a gram ratio)
80
70
60
50
40
30
20
10
0
Total for all feeding trials
Fig 2.23 Average % mass gain ( x ±SD) of mass per MR feeding category.
47
A similar result is obtained with the % mass gain for each prey-handling behavior within
each MR feeding category. Average % mass gains were different between each prey-handling
type within and across each MR feeding category but standard deviations overlap (Fig 2.24) An
experiment designed to pinpoint energetic factors for each prey-handling method is needed to
reveal potential differences.
100
90
% mass gain (a gram ratio)
80
70
60
Simple seizing
50
Pinion
Hairpin loop
40
Constriction
30
20
10
0
Fig 2.24 Average % mass gain ( x ±SD) for each prey-handling method within each MR feeding
category.
48
2. Time to begin prey handling
Time to begin prey-handling was not significantly different between the two mass ratio
feeding categories when snakes were ingestively naïve. However, time to begin prey-handling
was significantly different between the two mass ratio feeding categories for the entire study
(Results 2). Time to begin prey-handling for the small MR feeding category was
00:01:38±00:04:41 and 00:03:14±00:05:57 for the large MR category for the entire study (Fig
2.16). Average time to begin prey-handling was longer for the large MR feeding category but
the standard deviations widely overlap. There were five events in the small MR feeding category
in which the snakes took over ten minutes to begin prey-handling. There were six events in the
large MR feeding category in which the snakes took over ten minutes. The average times do
suggest that there is some factor impacting the large MR feeding category from a more
immediate time to begin prey-handling. There may be other variables at work that dictate when
a snake engages a potential prey item, whether it is offensive or defensive is not yet known. As
prey mass increases, so does prey movement. An evaluation of defense capabilities may be one
factor impacting the time to begin prey-handling because although prey activities increase, so
does the defense capabilities of the prey.
49
3. Capture position
During the first feeding trials when snakes were ingestively naïve, prey capture tended
toward the anterior regardless of category although the binomial test did not gain significance.
The large mass ratio feeding category tended more towards the anterior than the small mass ratio
feeding category.
Prey capture position tended toward the anterior as prey mass increased throughout the
entire study. In the small MR feeding category snakes captured to the anterior 94 times, the midbody 38 times, and the posterior 26 times. In the large MR feeding category, snakes captured to
the anterior 62 times, the mid-body 13 times, and the posterior 14 times (Fig 2.25).
100
90
80
Number of events
70
60
Anterior
50
Mid-body
40
Posterior
30
20
10
0
Fig 2.25 Total prey capture events for all 22 weeks.
50
The small MR feeding category captured to the anterior 59.49 %, the mid-body 24.05 %,
and the posterior 16.45 %. The large MR feeding category attacked to the anterior 69.66 %, the
mid-body 14.60 %, and the posterior 15.73 % (Fig 2.17). This observation corresponds with the
findings of both Diefenbach and Emslie (1971) and Mehta (2003).
Snakes in the small MR feeding category in the first 11 weeks captured to the anterior
57.14%, captured the mid-body 29.76%, and captured the posterior 13.09%. In the second 11
weeks of the trials the small MR feeding category captured to the anterior 62.16%, captured to
the mid-body 17.56%, and captured the posterior 20.27%. Snakes in the large MR feeding
category in the first 11 weeks captured to the anterior 67.74%, captured the mid-body 17.74%,
and captured the posterior 14.51%. In the second 11 weeks of trials the large MR feeding
category captured to the anterior 74.07%, captured the mid-body 7.40%, and captured the
posterior 18.51% (Fig 2.26). Snakes in the large MR feeding category attacked to the anterior
more frequently than the small MR feeding category in both the first and second 11 week
sections. In both the small and large MR feeding categories, prey capture position increased
towards the anterior as prey mass increased (from the first 11 weeks to the second 11 weeks).
51
100
90
80
Frequency (%)
70
60
50
Anterior
40
Mid-body
30
Posterior
20
10
0
First 11 weeks
Second 11 weeks
First 11 weeks
Second 11 weeks
Fig 2.26 Total prey capture frequencies for the first and second 11 weeks of trials.
52
Diefenbach and Emslie (1971) suggested that the movement of the mouse’s head attracts
the snake’s strike and my observations support the statement that snakes showed a more
aggressive response to more active mice (more specifically the head). More active mice tended
to have more mobile heads which could be the cue influencing the frequency of anterior capture
position. Cooper (1981) stated that attacks to the anterior ends of large prey are favored by the
resulting incapacitation of the prey’s major weapons. This would allow for a less hazardous
feeding process. In both the small and large MR feeding categories, frequency of capture to the
mid-body decreased in the second 11 weeks of the trials when compared to the first 11 weeks.
Perhaps it is more beneficial to avoid this capture position.
4. Prey-handling method
During the first feeding trials when snakes were ingestively naïve, simple seizing was the
most frequent prey-handling behavior although the binomial test did not gain significance. In the
small mass ratio feeding category snakes simply seized prey during six of the eight trials and
constricted the other two. In the large mass ratio feeding category snakes simply seized six of
the eight trials, pinioned once, and constricted once.
The frequency of prey-handling methods of snakes in both the small and mass ratio
feeding categories was significantly different than the expected frequency during the entire study.
In both MR feeding categories, snakes employed the four prey-handling behaviors, simple
seizing (SS), pinion (P), hairpin loop (HL), and constriction (C). Constriction was the most
frequently used prey-handling method (used 63.29% of the time in the small MR feeding
category and 74.15% in the large MR feeding category) for both MR feeding categories. As prey
got larger (in mass) snakes showed a tendency for more frequent constriction and less frequent
53
use of other prey-handling behaviors. In the first half of the study (first 11 weeks) the small MR
feeding category prey-handling behavior frequencies were; SS=50.00%, P=4.76%, HL=3.57%,
and C=41.66%. The small MR feeding category prey-handling behavior frequencies for the
second half of the study (second 11 weeks) were; SS=10.81%, P=0.00%, HL=1.35%, and
C=87.83%. The large MR feeding category frequencies (first 11 weeks) were; SS=32.25%,
P=3.22%, HL=1.61, and C=62.90%. The large MR feeding category frequencies (second 11
weeks) were; SS=0.00%, P=0.00%, HL=0.00%, and C=100.00%. The shift in most frequent
prey handling behavior in the small MR feeding category (as well as increasing frequency of
constriction in the large MR feeding category) through the first and second half of the feeding
trials suggests that there is either a tactile cue that snakes use in deciding prey-handling behavior
(the point at which this is decided remains unknown) or there is a learning process allowing
snakes to employ previously successful methods of prey-handling for prey of different sizes. As
prey mass increases, so does prey activity. This may be the cue the snake uses for employing
certain prey-handling behaviors. If this is true, as prey mass increases, so should the frequency
for constriction and the prey-handling frequency data support this statement.
The overall frequency shifts of prey-handling behaviors over the 22 week period suggests
an ontogenetic shift in prey-handling behavior in both the small and large mass ratio feeding
categories. The large mass ratio feeding category showed a faster shift towards constriction as
the dominant prey-handling behavior than the small mass ratio feeding category (Fig 2.27, 28).
With constriction being the most successful method of incapacitation for larger, more dangerous
prey, it would be advantageous to shift to a constriction dominated prey-handling repertoire.
This project is not able to identify the basis for the shift in behavior. The change in dominant
prey-handling frequencies could be due to maturation as muscle strength develops, a tactile or
54
chemical cue response, or a learned behavior that was successful in previous encounters with
prey.
100
Frequency (%)
80
60
Simple Seizing
Pinion
40
Hairpin Loop
20
Constriction
0
1 2 3 4
5 6 7 8
9 10 11
12 13 14
15 16 17
18 19 20
21 22
Week
Fig 2.27 Total frequencies of prey-handling behaviors for the small MR feeding category.
55
100
Frequency (%)
80
60
Simple Seizing
40
Pinion
20
Hairpin Loop
Constriction
0
1 2 3
4 5 6
7 8
9 10 11
12 13 14
15 16 17
18 19 20
21
Week
Fig 2.28 Total frequencies of prey-handling behaviors for the large MR feeding category.
56
This suggests that although both categories were mutually exclusive in the prey mass
ratio being fed, snakes are able to employ more advanced/effective prey-handling behaviors as
prey mass increased. As prey mass increases so does prey defense/offense. Both MR feeding
categories frequency for constriction increased as prey mass increased. This suggests that
constriction is the most effective prey-handling behavior for larger and more dangerous prey.
The method used the least in both MR feeding categories was the hairpin loop (used 2.53%
in the small MR feeding category and 1.12% in the large MR feeding category).
The
ineffectiveness of the hairpin loop may also be exaggerated by the small size of prey in relation
to the available coiling size of the snake. The hairpin loop appeared to be less tightly wound
than a complete coil of constriction. Simple seizing, pinion, and hairpin loop were not effective
in killing the prey. They seemed to be used more as a means to subdue the prey to prepare for
ingestion rather than killing the prey before ingestion.
5. Handedness
The frequency for one lateralization side dominance in both the small and large MR
feeding categories was not significantly greater than the expected frequencies of side dominances.
There appeared to be no discernable preference in either side of lateralization side dominance for
all 18 snakes as a group. Individual snakes in both MR feeding categories had a more frequent
side dominance than the other. The observations and frequencies are shown in Figure 2.29. All
of the snakes in the trial regardless of feeding category have the ability to constrict from both
sides with one exception (Snake #4). Snake #4 had 3 constriction events throughout the trials, all
of which were right handed. It is likely that more trials would have brought about the other
constriction pattern. Most of the snakes did show an individual preference for a dominant
57
handedness. This is a different observation than that of Willard (1977) regarding individuals not
preferring one side dominance but agrees with Willard regarding the species as a whole.
Further experimentation needs to be conducted to determine if preference for
lateralization side dominance exists among snakes. There are however additional variables to
consider in this behavior. Strike orientation, visual cues, prey response, and experience are just a
few areas to consider. It is not yet possible to infer a learned preference in this snake behavior
but it is something that may be influencing a “choice” reaction whether it is quantifiable or not.
Experimentation designed to specifically isolate individual variables is needed to give some
insight into this area of snake science.
14
Number of events
12
10
8
6
Left-handed
4
Right-handed
2
0
Fig 2.29 Lateralization side dominance observations for constriction events.
58
6. Time to subdue prey
During the first week of feeding trials when snakes were ingestively naïve, the time to
subdue prey was not significantly different between the two mass ratio feeding categories.
Average time to subdue prey did not differ significantly between the two mass ratio feeding
categories for the entire study (Results 6). The average times are very close to one another and
the standard deviations are also similar (Fig 2.30). These observations support the idea that
snakes are able to subdue prey, regardless of mass and maturity, within a short and consistent
time period (using various prey-handling methods). This also supports the idea that preyhandling behaviors are more of a constant event with a more stable time for each behavior and is
less dependent on the mass of prey being handled.
0:08:38
0:07:12
0:05:46
Time
0:04:19
0:02:53
0:01:26
0:00:00
Mean time to subdue
Fig 2.30 Mean time ( x ±SD) to subdue prey for both MR feeding categories.
59
The average time to subdue prey varied for each prey-handling behavior (regardless of
category) (Fig 2.31). Constriction took the longest amount of time to subdue the prey
(0:04:07±0:04:18). Which was due to the condition of the prey after the prey-handling event.
Prey were more frequently killed when constriction was used. There were only two preyhandling events that were not constrictions that resulted in prey death before ingestion. One was
a hairpin loop and the other was a simple seizing that appeared to break the mouse’s neck upon
strike impact. All other deaths in the study came from constriction (a total of 122). This
explains why the time to subdue using constriction is longer than the other three prey-handling
methods. The usual outcome of constriction is death of prey before ingestion whereas the usual
outcome of the other three prey-handling behaviors leaves the prey alive before ingestion. This
also supports the idea that simple seizing, pinion, and hairpin loop are all forms of what I am
calling “incapacitation behaviors”. The behaviors do not usually result in prey death and appear
to be used primarily as a stabilizing source while the snake swallows the prey alive.
60
0:10:05
0:08:38
0:07:12
Time
0:05:46
Simple Seizing
Pinion
0:04:19
Hairpin Loop
Constriction
0:02:53
0:01:26
0:00:00
Average time to subdue
Fig 2.31 Mean time ( x ±SD) to subdue prey for each prey-handling behavior (regardless of
category).
61
Time to subdue prey varied among the four prey-handling behaviors (Fig 2.32). Simple
seizing took longer in the large MR feeding category (0:02:42±0:06:37) than it took for the small
MR feeding category (0:00:39±0:00:30) but with the standard deviations considered, there is no
discernable biological significance between the two MR feeding categories simple seizing times
(Fig 2.33).
0:11:31
0:08:38
0:05:46
0:02:53
0:00:00
Simple Seizing
Pinion
Hairpin Loop Constriction
Fig 2.32 Mean time ( x ±SD) to subdue prey for each prey-handling behavior.
62
0:11:31
0:08:38
Time
0:05:46
0:02:53
0:00:00
Average Time to subdue prey
Fig 2.33 Mean time ( x ±SD) to subdue prey using the simple seizing prey-handling behavior.
63
The average time to subdue prey using the pinion method did not vary greatly between
the two categories (0:02:14±0:01:44 for the small MR feeding category and 0:02:23±0:00:03 for
the large) (Fig 2.34). With the standard deviation of the small MR feeding category being so
large, it is not possible to draw a conclusion on any differences between the two categories in
regards to biological significance. Even without the standard deviations considered there is only
a 0:00:09s difference between the two averages. This supports the idea that pinioning is used to
hold the prey while the snake orients itself to the swallowing position and that would not be
impacted greatly by the size of the prey if the prey item was secured properly. Orienting towards
the anterior/posterior portion of a prey item would be a time factor for the snake itself and not the
prey.
0:04:19
0:03:36
Time
0:02:53
0:02:10
0:01:26
0:00:43
0:00:00
Average time to subdue prey
Fig 2.34 Mean time ( x ±SD) to subdue prey using the pinion prey-handling behavior.
64
Average time to subdue prey using the hairpin loop method varied between the two MR
feeding categories. The small MR feeding category subdued prey in 0:00:44±0:00:27 using the
hairpin loop while the large MR feeding category took 0:04:30 (Fig 2.35). There is no standard
deviation for the large MR feeding category because there was only one event in which a snake
used the hairpin loop. Hairpin loop never seemed to be effective as a prey-handling method for
killing the prey. None of the hairpin loop events in the small MR feeding category (a total of 4)
killed the prey before ingestion while the one event in the large MR feeding category killed the
prey before ingestion. From an observational standpoint, the hairpin loop is the most ineffective
method of prey control for ingestion regardless of prey condition at ingestion. Snakes appeared
to struggle more with this method than the other three options. Rather, prey appeared to be able
to struggle more when in a hairpin loop. Of the pinioning methods, a hairpin loop offers the two
smallest points of contact (being two points of the snake’s body). This seems to allow more
movement from the prey which in turn creates a more difficult swallowing process.
65
0:05:02
0:04:19
Time
0:03:36
0:02:53
0:02:10
0:01:26
0:00:43
0:00:00
Fig 2.35 Mean time ( x ±SD) to subdue prey using the hairpin loop method.
66
Mean time to subdue prey using constriction differed between the two MR feeding
categories but with standard deviations included there is no discernable difference between the
two times. The small MR feeding category took 0:04:28±0:04:46 while the large MR feeding
category took 0:03:36±0:03:03 (Fig 2.36). The averages seem counterintuitive from what is
expected. It would seem easier to subdue a smaller prey item with constriction than a larger one
even though the averages tell a different story. Smaller prey have a smaller diameter and would
therefore require a smaller portion of the snake’s body for constriction. Larger prey have a
larger diameter and would require more of the snake’s body for constriction. It could be that a
larger body portion used for constriction is more effective at subduing prey because there is more
muscle strength to be used per coil on a larger prey item than a smaller one. There isn’t much
that a prey item can do to get out of a constriction pattern once caught in it so it may just be a
matter of more muscle being more effective regardless of what prey is caught in the constriction.
67
0:10:05
0:08:38
0:07:12
Time
0:05:46
0:04:19
Large MR feeing category
0:02:53
0:01:26
0:00:00
Fig 2.36 Mean time ( x ±SD) to subdue prey using the constriction prey-handling method.
68
7. Direction of ingestion
During the first week of feeding trials when snakes were ingestively naïve, the frequency
for anterior ingestion was significantly greater than frequency for posterior ingestion in both the
small and large mass ratio feeding categories.
Direction of ingestion for corn snakes differed between the two MR feeding categories
during the entire study. For the small MR feeding category, snakes swallowed prey head-first
140 times and swallowed tail-first 18 times. The frequency of head-first ingestion in the small
MR feeding category was 88.60% and 95.50% for the large MR feeding category. The
frequency for tail-first ingestion for the small MR feeding category was 11.39% and 4.49% for
the large MR feeding category (Fig 2.37).
100
90
80
Frequency (%)
70
60
Head-first
50
Tail-first
40
30
20
10
0
Fig 2.37 Total directional ingestion frequencies for both MR feeding categories.
69
On their first feeding trial, seven of the eight corn snakes in the small MR feeding
category and seven of eight trials in the large MR feeding category ingested prey headfirst. This
observation also corresponds with Klein and Loop (1975) in assuming the tendency for head-first
ingestion is inherited. This also agrees with the statement made by Diefenbach and Emslie (1971)
in which the direction of hair as well as chemoreception may be the primary tactile cues for
ingestion. In the first trials all of the mice were hairless. In the small MR feeding category there
were 68 feeding trials with pinkies (a completely hairless mouse) and 77 trials with haired mice.
In trials with hairless mice in the small MR feeding category, mice were ingested head-first
77.94% of the time. In trials with haired mice, mice were ingested head-first 96.10% of the time.
In trials with hairless mice in the large MR feeding category, mice were ingested head-first 80.00%
of the time. In trials with haired mice, mice were ingested head-first 100.00% of the time (Fig
2.38).
100
90
80
Frequency (%)
70
60
Hairless mice
50
Haired mice
40
30
20
10
0
Fig 2.38 Frequency of head-first ingestion of hairless and haired mice.
70
This observation suggests that direction of hair on prey items may be a factor impacting
direction of ingestion but may not be the primary tactile cue used to determine direction of
ingestion. There was still a tendency for head-first ingestion with hairless mice but the
frequency increased with hair present. An observation noted by Diefenbach and Emslie (1971)
was also observed in this study. Snakes that released prey upon subduing appeared to “tongue”
the prey. This is most likely done for chemoreception as tongue flicking uses the Jacobson’s
organ for chemical processing (specifically, each fork of the tongue for directional
chemoreception). Chemical cues and original capture position are possible factors impacting
direction of ingestion. Out of the 154 trials in which snakes attacked the anterior (across both
categories), 153 of them proceeded to ingest the prey head-first. Of the 40 trials where prey
were captured by the posterior section, 33 of them proceeded to ingest the prey head-first. Of the
49 trials where prey were captured by the mid-body, 35 of them proceeded to ingest the prey
head-first.
This observation supports the idea that swallowing position is impacted by capture
position but it is not the only factor. The most frequent direction of ingestion was head-first
regardless of capture position but was most frequent in prey captured by the anterior section and
least frequent in prey captured by the posterior section.
71
8. Condition of prey at ingestion
During the first week of feeding trials when snakes were ingestively naïve, live prey were
ingested more often than dead prey for both the small and large mass ratio feeding categories.
The condition of prey at ingestion varied between the two MR feeding categories over the
entire study. The majority of the small MR feeding categories mice were swallowed alive. Of
the successful 158 trials in the small MR feeding category, 90 mice were swallowed alive and 68
mice were killed before ingestion. The majority of the large MR feeding categories mice were
killed before swallowing. Of the 89 successful trials in the large MR feeding category, 33 were
swallowed alive and 56 were killed before ingestion. Mice in the small MR feeding category
swallowed prey alive 56.96% of the time and killed mice before ingestion 43.03% of the time.
Mice in the large MR feeding category swallowed prey alive 37.07% of the time and killed mice
before ingestion 62.92% of the time. Comparing the differences between the two categories,
snakes in the larger MR feeding category killed the mice before ingestion more often than the
snake in the smaller MR feeding category. There was also a shift in frequencies across the
feeding trials. In the small MR feeding category, snakes ingested prey alive 85.71% and killed
prey before ingestion 14.28% in the first 11 weeks. Prey were swallowed alive 24.32% of the
time and killed before ingestion 75.67% of the time in the second 11 weeks. In the large MR
feeding category, snakes ingested prey alive 53.22% and killed prey before ingestion 46.77% in
the first 11 weeks. Prey were killed 100.00% of the time in the second 11 weeks. As prey mass
increased (from small to large categories as well as the progression throughout the trials) so did
the tendency for mice to be killed prior to ingestion. This suggests that snakes have the ability to
alter their handling tactics for different prey masses regardless of the mass-ratio of prey.
72
In both the small and large feeding categories there was a shift in dominant frequency of
the condition of prey at ingestion. In the small mass ratio feeding category, the frequency for
dominant condition of prey ingested began to switch from alive to dead during week 13 to week
15 (Fig 2.39). In the large mass ratio feeding category, the frequency for dominant condition of
prey ingested began to switch from alive to dead during week 6 to week 8 (Fig 2.40).
Small prey condition
Frequency(%)
100
80
60
40
Alive
20
Dead
0
1 2 3 4
5 6 7 8
9 10 11
12 13 14 15
16 17 18
19 20 21
22
Week
Fig 2.39 Frequency of condition of prey at ingestion for the small mass ratio feeding category.
73
Large prey condition
Frequency(%)
100
80
60
40
20
Alive
0
Dead
1 2 3 4
5 6 7 8
9 10 11
12 13 14
15 16 17
18 19 20
21
Week
Fig 2.40 Frequency of condition of prey at ingestion for the large mass ratio feeding category.
74
Regardless of age and development, snakes are able to match prey-handling methods to
prey mass. As prey mass increases so does the defense of the mouse. It would be advantageous
to kill prey that are potential threats during the ingestion process. This observation provides
support for the idea that snakes switch prey-handling behaviors based upon the prey mass and
may not rely on a temporal ontogenetic shift.
9. Time to ingest
During the first week of feeding trials when snakes were ingestively naïve, time to ingest
prey was significantly different between the small and large mass ratio feeding categories.
Time to ingest prey varied between the two MR feeding categories for the entire study. It
was also the longest individual timed aspect of the study. Average time to ingest prey was nearly
3 times longer in the large MR feeding category (0:16:36±0:09:56) than the small MR feeding
category (0:06:56±0:03:25) (Fig 2.42). This can be explained by the gape limitations of snakes.
As prey girth increases so does ingestion time. Prey girth was not specifically measured but the
girth does increase as prey mass increases.
75
0:28:48
0:25:55
0:23:02
0:20:10
0:17:17
0:14:24
0:11:31
0:08:38
0:05:46
0:02:53
0:00:00
Average time to ingest
Fig 2.41 Mean time ( x ±SD) to ingest prey for both MR feeding categories.
76
Average time to ingest prey varied between head-first and tail-first ingestion. Average
head-first ingestion was 0:10:37±0:08:16 and tail-first ingestion was 0:08:29±0:04:37 (Fig 2.42).
Average time to directionally ingest per category is shown in Figure 2.43.
0:20:10
0:17:17
Time
0:14:24
0:11:31
Head-first
0:08:38
Tail-first
0:05:46
0:02:53
0:00:00
Average time to ingest
Fig 2.42 Mean time ( x ±SD) to ingest of directional ingestion for both MR feeding categories
(as one group).
77
0:28:48
0:25:55
0:23:02
0:20:10
Time
0:17:17
0:14:24
Head-first
0:11:31
Tail-first
0:08:38
0:05:46
0:02:53
0:00:00
Fig 2.43 Mean time ( x ±SD) to ingest of directional ingestion for each MR feeding category.
78
With standard deviations included there is no discernable biological significance between
the two modes of ingestion as the head-first standard deviation fully encompasses the tail-first
standard deviation. It seems odd that the average time to ingest head-first took longer than the
average time to ingest tail-first. Swallowing an object at the narrow end first would seem to be
more efficient but the data do not support that idea. This may also be explained by the idea of
snake development throughout the trials. A majority of prey swallowed tail-first were done in
the earlier parts of the experiments when prey were smaller; all were swallowed head-first after
week 9 of trials. Earlier trials would also have a smaller snake to prey girth ratio. As mentioned
earlier, as prey mass increased, so should the time to ingest prey (in this study) because mouse
girth increased at a faster rate than snake girth.
10. Total feeding duration
During the first week of feeding trials when snakes were ingestively naïve, total feeding
duration was not significantly different between the small and large mass ratio feeding categories.
Total feeding duration was significantly different between the small and large MR
feeding categories over the entire study (Results 9). Total feeding duration is just an
accumulation of the various times of interactions between the corn snakes and their prey. A
longer feeding event would not be advantageous to a snake. The longer the snake is spending
with a prey item the longer it exposes itself to potential predation. It would be advantageous to
choose the optimum ratio of handling time and energetic gain.
79
11. Failure rates of feeding events
Failure rates during feeding trials were higher in the large MR feeding category than the
small MR feeding category. Rates were highest in the second 11 weeks in the large MR feeding
category. Average failed feeding trials for the small MR feeding category were 0.365% for the
first 11 weeks and 15.90% for the second 11 weeks. Average failed feeding trials for the large
MR feeding category were 29.54% for the first 11 weeks and 59.70% for the second 11 weeks.
The average failure rates for the entire 22 week trial were 15.05% for the small MR feeding
category and 42.58% for the large MR feeding category. These averages suggest that larger
mice (regardless of size ratio category) are more frequently rejected than smaller mice (Fig 2.44).
This may have some ecological significance of successful prey capture in the wild. If a snake
refuses a prey item (or fails to capture a prey item) in a similar fashion as the laboratory study
then the natural food range of a snake species may be more narrow than the prey that are
ingestively possible to be eaten. This means that although a snake might be able to swallow the
prey, it might not be physically capable of capturing it.
80
Frequency (%)
100
80
60
40
20
0
1 2 3 4 5
6 7 8 9
10 11 12 13
14 15 16 17
18 19 20 21
22
Week
Fig 2.44 Feeding trial failure frequencies for both the small and large MR feeding categories.
81
CHAPTER 5
CONCLUSIONS
Evidence in this study showed:
1.
Snake growth (over the entire study)
Regardless of category (i.e. regardless of how food is presented), snake growth in mass,
length, and girth was significantly related to the total amount of food consumed. At the end of
the study, the larger snakes had higher shed frequencies than the smaller snakes.
2.
Prey-handling behaviors (Ingestively naïve)
Time to begin prey-handling, time to subdue prey, and total feeding duration were similar
between the small and large MR feeding categories. Regardless of prey size, ingestively naïve
snakes perform these three tasks in a similar fashion. Time to ingest prey was, however,
different between the small and large MR feeding categories. Larger prey took a longer amount
of time to ingest than smaller prey. Prey capture tended toward the anterior regardless of
category with the large category having a stronger tendency. Three (simple seizing, pinion, and
constriction) of the four known prey-handling behaviors of non-venomous snakes were
employed during the time when snakes were ingestively naïve. Simple seizing was the most
frequent prey-handling behavior. The frequency for anterior (head-first) ingestion was
significantly greater than posterior ingestion for both MR feeding categories. All prey were
swallowed alive (regardless of the prey-handling method used).
82
3.
Prey-handling behaviors (Entire study)
Time to begin prey-handling, time to ingest, and total feeding duration was different
between the two mass ratio feeding categories. Time to subdue was not different between the
two MR feeding categories. Anterior prey capture increased in frequency as prey mass increased
(between the two categories as well as through time). All four of the known prey-handling
behaviors of non-venomous snakes were used during the entire study. Initially simple seizing
was the most frequently used handling behavior but as prey mass increased (as well as time) the
most frequent prey-handling method used was constriction. The change in frequency occurred in
both categories but occurred at a faster rate in the large MR feeding category. Corn snakes as a
group did not show a significant preference for right or left sided lateralization side dominance,
however, individual snakes may have used one side more frequently than the other. Snakes
swallowed prey by the anterior significantly more frequently than by the posterior. Larger prey
and prey with hair were more frequently swallowed by the anterior than small and hairless prey.
As prey mass increased, so did the tendency for prey to be killed prior to ingestion ( both in and
among categories). Prey were more frequently left alive at ingestion in the small MR feeding
category but killed before ingestion more frequently in the large MR feeding category. As prey
mass increased (regardless of category) so did the frequency of failed feeding events. Failure
rates were highest in the large MR feeding category.
83
CHAPTER 6
LITERATURE CITED
Ashton, K. G. (2002). Headfirst ingestion of prey by rattlesnakes: Are tactile cues used?. Journal
of Herpetology, 36(3), 500-502.
Barnard, S. M., Hollinger, T. G., & Romaine, T. A. (1979). Growth and food consumption in the
corn snake, Elaphe guttata guttata (Serpentes: Colubridae). American Society of Ichthyologists
and Herpetologists, 1979, 739-741.
Bartlett, R. D., & Bartlett, P. P. (1996). Corn snakes and other rat snakes. Hauppauge, NY:
Barron's.
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Conant, R., & Collins, J. T. (1992). Peterson guide to reptiles and amphibians. Boston, NY:
Houghington Mifflin.
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de Queiroz, A. (1984). Effects of prey type on the prey-handling behavior of the bull snake,
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2010. http://snakebytes.tv/index.php?option=com_content&task=view&id=61&Itemid=14.
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snake, Regina alleni. Herpetologica, 30(1), 91-94.
Greene, H. W., & Burghardt, G. M. (1978). Behavior and phylogeny: Constriction in ancient and
modern snakes. Science, 200(4377), 74-77.
Heinrich, M. L., & Klaassen, H. E. (1985). Side dominance in constricting snakes. Journal of
Herpetology, 19(4), 531-533.
Henderson, R. W. (1970). Feeding behavior, digestion, and water requirements of Diadophis
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84
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Mori, A. (1993). Does feeding experience with different size of prey influence the subsequent
prey-handling behavior in Elaphe climacophora?. Ethology, 11, 153-156.
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growth of neonatal garter snakes (Thamnophis sirtalis). Journal of Herpetology, 7, 225-229.
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Herpetologists, 1977, 379-382.
85
Snake Snake
#1 mass
Week #1
5.5
2
6.2
3
6.7
4
7
5
7.5
6
8.6
7
8.8
8
9.1
9 10.4
10
12
11
16
12 15.9
13
18
14
22
15 22.5
16 25.4
17 28.9
18 35.7
19 35.9
20 42.5
21 43.9
22 50.4
86
Prey
mass
1.4
1.8
1.6
2.2
2.1
1.9
2
3
3.9
4.3
3.5
6.1
7
5.3
6.1
5.7
10.8
8.2
12.3
8.7
9.9
14.3
6/26/2010
7/26/2010
8/23/2010
9/20/2010
10/18/2010
11/15/2010
32.4
33.2
37.2
47.9
50.8
51.2
2.0
2.2
2.5
3.0
3.6
3.8
Girth
(CM)
Prey
Capture handling
position method
m
c
a
c
p
hl
a
ss
p
c
a
c
m
c
m
c
a
c
a
c
a
c
p
c
p
c
a
c
p
c
p
c
p
c
a
c
a
c
a
c
m
c
a
c
Monthly
Straight Line length (CM)
Measurements
Prey
characteristic
pinkie
pinkie
pinkie
pinkie
pinkie
pinkie
pinkie
pinkie
fuzzie
fuzzie
fuzzie
crawler
crawler
fuzzie
crawler
fuzzie
hopper
hopper
juv mouse
hopper
hopper
juv. mouse
Time to
begin
prey
handling
0:00:31
0:00:06
0:00:08
0:00:05
0:00:06
0:00:13
0:00:04
0:00:05
0:00:02
0:00:03
0:00:02
0:00:03
0:00:03
0:00:06
0:00:06
0:00:07
0:00:07
0:00:04
0:00:03
0:02:44
0:00:29
0:00:12
6/24/2010
8/9/2010
9/12/2010
10/4/2010
11/5/2010
Shed Date
Time
Prey
Swallow to
Handedness condition position subdue
r
a
a
0:01:51
a
a
0:00:14
r
a
p
0:00:22
a
a
0:00:05
r
a
p
0:01:27
r
a
a
0:00:57
r
a
a
0:01:36
r
d
a
0:04:13
l
d
a
0:04:27
l
a
a
0:01:06
l
a
a
0:03:20
l
d
a
0:03:28
l
d
a
0:03:36
l
a
a
0:01:55
r
a
a
0:06:23
l
a
a
0:04:26
r
a
a
0:11:47
l
d
a
0:05:18
l
d
a
0:05:09
r
d
a
0:02:54
r
d
a
0:08:13
r
d
a
0:03:04
Time Total
to
feeding
ingest duration
0:03:43 0:06:05
0:04:10 0:04:30
0:03:31 0:03:59
0:04:13 0:04:55
0:07:04 0:08:37
0:03:15 0:04:25
0:02:51 0:04:31
0:03:33 0:07:51
0:07:54 0:12:23
0:06:17 0:06:17
0:05:18 0:05:18
0:07:50 0:07:50
0:13:51 0:17:30
0:06:52 0:08:53
0:07:00 0:13:29
0:04:51 0:09:24
0:12:38 0:24:32
0:06:10 0:11:32
0:11:12 0:16:24
0:04:57 0:10:43
0:02:47 0:11:12
0:11:16 0:14:20
v to a
v to a
v to a
d to a
both
both
Dorsal
or
ventral
d to a
entire body
middle 1/3
1st 1/3
back 2/3
1st 2/3
mid 1/3
1st 1/3
1st 1/3
1st 1/3
Body
Portion
used for
constriction
1st 1/3
Retracted
Rotated prey Strikes prey/did
or rotated
prior to not
around prey capture retract
rotated prey
2 retracted
1 retracted
0 retracted
0 retracted
rotated prey
0 retracted
rotated prey
5 retracted
rotatedaround
0 retracted
rotated around
0 retracted
rotated prey
0 did not
0 retracted
0 retracted
0 retracted
0
0
0
0
0 did not
0
0
1 did not
2
0
APPENDIX A
OBSERVATIONS OF SNAKE #1
Snake Snake
#2 mass
Week #1
3.9
2
4.3
3
4.6
4
5.4
5
6.0
6
7.0
7
8.6
8
8.2
9
9.0
10
9.8
11 11.4
12 13.0
13 13.9
14 16.8
15 18.5
16 19.8
17 21.6
18 26.3
19 29.3
20 27.8
21 29.4
22 33.0
87
5.9
6.5
8.8
0:00:49 m
0:00:47 p
0:02:13 a
7/5/2010
8/2/2010
8/30/2010
9/27/2010
10/25/2010
11/22/2010
28.3
31.0
37.1
44.6
54.1
56.2
c
c
c
1.6
2.2
2.4
2.5
2.8
3.0
Girth
(CM)
Prey
Capture handling
Position method
a
ss
a
ss
a
c
a
ss
p
c
m
c
a
c
a
hl
a
ss
m
c
a
c
a
ss
m
c
a
c
a
c
a
c
a
c
a
c
Monthly
Measurements
fuzzie
fuzzie
hopper
Prey
Prey
characteristic mass
pinkie
1.5
pinkie
1.3
pinkie
1.8
pinkie
1.8
pinkie
1.7
pinkie
2.0
pinkie
2.6
pinkie
1.8
pinkie
2.6
pinkie
2.6
fuzzie
4.4
fuzzie
3.5
fuzzie
4.9
fuzzie
4.3
fuzzie
4.8
fuzzie
5.0
fuzzie
7.9
fuzzie
5.5
Time to
begin
prey
handling
0:01:32
0:00:54
0:01:02
0:00:19
0:00:06
0:00:24
0:00:18
0:00:05
0:00:13
0:00:09
0:00:55
0:01:56
0:00:20
0:00:09
0:00:29
0:00:29
0:00:01
0:00:18
r
r
l
7/3/2010
8/22/2010
9/5/2010
9/27/2010
11/14/2010
Shed Date
d
d
d
a
a
a
0:12:35
0:09:25
0:14:27
Time Total
to
feeding
ingest duration
0:12:16 0:14:17
0:04:46 0:05:55
0:04:59 0:11:25
0:04:58 0:05:44
0:04:27 0:05:04
0:05:33 0:09:12
0:07:40 0:10:13
0:03:07 0:04:53
0:03:16 0:04:10
0:07:00 0:08:12
0:08:15 0:14:01
0:04:27 0:06:30
0:07:13 0:17:10
0:05:39 0:09:33
0:08:13 0:09:50
0:06:54 0:13:36
0:08:22 0:10:45
0:14:56 0:21:12
0:06:46 0:05:00
0:03:12 0:06:13
0:01:55 0:10:21
Time
Prey
Swallow to
a
a
0:00:29
a
a
0:00:15
l
d
a
0:05:24
a
a
0:00:27
l
a
a
0:00:31
l
a
a
0:03:15
r
a
a
0:02:15
a
a
0:01:23
a
a
0:00:41
l
a
a
0:01:03
l
a
a
0:04:49
a
a
0:00:07
ventral
d
a
0:09:37
r
d
a
0:03:45
r
a
a
0:00:08
l and r
d
a
0:06:11
l
d
a
0:02:22
l
d
a
0:05:58
2 did not
0 did not
0 did not
Body
Retract
Dorsal portion
or
used for
or rotated
prior to not
ventral constriction around prey capture retract
11 retracted
0 retracted
v to a entire body rotated prey
2 retracted
0 retracted
v to a 1st 1/3
rotated around
0 retracted
v to a 1st 1/3
rotated prey
2 retracted
d to a entire body
2 retracted
rotated around
0 retracted
2 retracted
1st 2/3
0 retracted
12 retracted
12 retracted
3 retracted
1st 1/3
0 retracted
mid 1/3
0 retracted
0 retracted
0 did not
0 did not
APPENDIX A
Snake Snake
#3 mass
Week #1
5.5
2
6.5
3
7.5
4
8.0
5
9.1
6
9.8
7 10.4
8 11.2
9 13.0
10 14.2
11 16.7
12 18.9
13 20.0
14 25.3
15 22.4
16 24.9
17 26.8
18 31.0
19 32.7
20 38.0
21 41.6
22 47.5
88
4.5
5.9
6.0
7.5
11.4
8.4
9.4
15.7
0:00:03
0:00:02
0:00:03
0:00:37
0:00:38
0:00:01
0:00:50
0:00:02
p
m
p
p
a
a
a
m
6/28/2010
7/26/2010
8/23/2010
9/20/2010
10/18/2010
11/15/2010
32.9
38.4
44.6
48.2
51.2
53.4
c
c
c
c
c
c
c
c
2.4
2.8
2.7
3.0
3.4
3.5
Girth
(CM)
Prey
Capture handling
position method
m
ss
m
ss,c
a
ss
a
c
a
ss
a
ss
m
ss,c
m
ss
a
ss,c
p
c
p
c
m
c
p
c
Monthly
Measurements
fuzzie
fuzzie
fuzzie
crawler
hopper
hopper
hopper
juv. mouse
Prey
Prey
characteristic mass
pinkie
1.3
pinkie
2.2
pinkie
2.2
pinkie
2.4
pinkie
2.2
pinkie
2.1
pinkie
2.1
fuzzie
3.1
fuzzie
3.6
fuzzie
5.4
fuzzie
3.5
fuzzie
4.5
crawler
7.2
Time to
begin
prey
handling
0:00:18
0:00:11
0:00:33
0:00:50
0:00:07
0:00:04
0:00:06
0:00:06
0:00:02
0:00:14
0:00:03
0:00:02
0:00:03
r
r
l
l
l
l
r
r
6/22/2010
7/2/2010
9/6/2010
10/4/2010
11/2/2010
11/23/2010
Shed Date
d
d
d
d
d
d
d
d
a
a
a
a
a
a
a
a
0:04:32
0:03:10
0:06:01
0:01:35
0:00:34
0:02:59
0:05:22
0:04:08
Time
Prey
Swallow to
a
p
0:01:11
r
a
a
0:01:06
a
a
0:00:14
r
a
a
0:02:05
a
a
0:00:11
a
a
0:00:21
l
a
p
0:05:05
a
a
0:01:13
r
d
a
0:00:56
l
d
a
0:19:16
r
a
a
0:04:03
l
a
p
0:10:11
r
d
a
0:02:19
0:04:05
0:07:25
0:05:22
0:08:44
0:02:08
0:06:34
0:10:00
0:14:17
0:08:39
0:10:37
0:11:23
0:10:56
0:11:12
0:09:34
0:16:12
0:18:25
Time Total
to
feeding
ingest duration
0:06:28 0:07:47
0:09:13 0:10:30
0:04:46 0:05:33
0:05:18 0:08:13
0:04:41 0:04:59
0:03:07 0:03:32
0:03:07 0:08:37
0:01:09 0:07:28
0:07:03 0:08:01
0:07:24 0:30:48
0:04:40 0:08:46
0:11:13 0:21:26
0:09:06 0:11:27
entire body
entire body
0
0
0
6
0
0
5
0
did not
did not
did not
did not
did not
did not
did not
did not
Body
Retracted
Dorsal portion
or
used for
or rotated
prior to not
0 retracted
d to a 1st 1/3
0 retracted
0 retracted
rotated around
0 retracted
0 retracted
0 retracted
both
entire body rotated around
0 retracted
1 retracted
1st 1/3
0 did not
1st 1/3
0 did not
1st 1/3
0 did not
0 did not
0 did not
APPENDIX A
Snake Snake
#4 mass
Week #1
4.1
2
4.6
3
5.0
4
5.5
5
6.2
6
6.8
7
7.3
8
8.0
9
8.3
10
8.9
11
9.4
12 11.8
13 10.7
14 11.9
15 13.5
16 15.8
17 14.7
18 16.4
19 18.4
20 21.0
21 20.4
22 21.4
89
3.1
5.3
5.3
4.3
8.4
fuzzie
fuzzie
fuzzie
fuzzie
hopper
0:14:12 a
0:10:25 a
0:02:11 a
0:03:12 a
0:27:12 m
0:00:30 a
0:00:45 a
0:00:45 a
7/5/2010
8/2/2010
8/30/2010
9/27/2010
10/25/2010
11/22/2010
30.0
32.7
37.9
38.4
42.7
44.8
ss
c
ss
c
c
ss
ss
ss
2.2
2.6
2.5
2.6
2.6
2.8
Girth
(CM)
r
r
r
6/30/2010
8/23/2010
10/25/2010
11/20/2010
Shed Date
a
d
a
d
d
a
a
a
Prey
Capture handling
Prey
Position method Handedness condition
a
ss
a
a
ss
a
m
p
a
a
ss
a
m
ss
a
m
ss
a
a
ss
a
a
ss
a
m
ss
a
a
ss
a
a
ss
a
Monthly
Measurements
3.5
4.0
3.5
fuzzie
fuzzie
fuzzie
Prey
Prey
characteristic mass
pinkie
1.6
pinkie
1.6
pinkie
1.9
pinkie
2.0
pinkie
1.8
pinkie
1.5
pinkie
2.6
pinkie
1.7
pinkie
1.8
pinkie
2.6
fuzzie
3.5
Time to
begin
prey
handling
0:07:06
0:00:48
0:00:42
0:00:24
0:00:17
0:00:33
0:01:09
0:01:14
0:00:20
0:00:18
0:00:26
a
a
a
a
a
a
a
a
0:00:01 0:07:11
0:09:35 0:17:12
0:00:27 0:03:32
0:04:37 0:19:21
0:07:22 0:09:06
0:21:13
0:37:12
0:06:10
0:27:10
0:43:16
0:07:05
0:08:54
0:07:16
0 retracted
0 retracted
0 retracted
0 retracted
0 retracted
0 retracted
0 retracted
0 retracted
Body
Retracted
Time Total
Dorsal portion
Roteted prey Strikes prey/did
to
feeding or
used for
or rotated
Prior to not
ingest duration ventral constriction around prey capture retract
0:07:26 0:15:56
2 did not
0:06:19 0:07:29
0 retracted
0:06:05 0:12:10
6 did not
0:05:29 0:06:25
0 did not
0:06:34 0:09:38
0 retracted
0:04:07 0:05:11
0 retracted
0:06:48 0:09:36
0 retracted
0:04:08 0:05:53
0 retracted
0:03:40 0:05:26
0 retracted
0:04:42 0:05:42
0 retracted
0:08:47 0:09:57
0 retracted
0:00:41 0:05:54
0:00:27 0:07:42
0:00:40 0:05:51
Time
Swallow to
position subdue
a
0:01:24
a
0:00:22
a
0:04:23
a
0:00:32
a
0:02:48
p
0:00:31
a
0:01:35
a
0:00:31
p
0:01:26
a
0:00:42
a
0:00:44
APPENDIX A
Snake Snake
#5 mass
Week #1
3.8
2
4.4
3
4.6
4
5.1
5
5.5
6
6.5
7
7.3
8
7.6
9
7.9
10
8.8
11
9.8
12 11.4
13 12.2
14 13.8
15 16.4
16 16.8
17 18.3
18 23.4
19 21.4
20 24.8
21 26.6
22 29.6
90
6.2
5.1
5.7
0:00:56 a
0:00:45 a
0:04:12 a
7/5/2010
8/2/2010
8/30/2010
9/27/2010
11/25/2010
11/22/2010
28.2
30.3
36.0
40.0
43.9
46.6
c
c
c
2.1
2.4
2.4
2.6
3.2
3.4
Girth
(CM)
Prey
Capture handling
position method
a
ss
p
ss
m
ss
a
ss
p
c
a
ss
a
p
a
ss
m
c
p
c
a
c
m
c
m
c
m
c
a
c
a
c
a
c
Monthly
Measurements
crawler
fuzzie
fuzzie
Prey
Prey
characteristic mass
pinkie
1.5
pinkie
1.5
pinkie
1.6
pinkie
1.5
pinkie
1.7
pinkie
1.7
pinkie
2.8
pinkie
1.9
pinkie
2.3
pinkie
2.1
fuzzie
3.8
fuzzie
3.3
pinkie
2.7
fuzzie
3.9
fuzzie
4.7
fuzzie
3.9
crawler
7.0
Time to
begin
prey
handling
0:00:29
0:00:21
0:00:17
0:00:39
0:00:34
0:03:10
0:00:38
0:00:14
0:00:08
0:00:11
0:00:34
0:00:11
0:03:10
0:00:26
0:01:32
0:00:51
0:00:28
r
l and r
r
6/30/2010
8/15/2010
9/20/2010
10/18/2010
11/8/2010
Shed Date
d
d
d
a
a
a
0:13:25
0:08:37
0:11:25
Time Total
to
feeding
ingest duration
0:08:47 0:09:44
0:11:49 0:12:41
0:11:23 0:12:07
0:06:04 0:07:17
0:14:50 0:16:40
0:04:51 0:09:11
0:07:28 0:10:59
0:03:40 0:04:24
0:04:48 0:07:52
0:11:32 0:13:35
0:12:31 0:15:01
0:05:15 0:10:10
0:05:03 0:10:14
0:05:45 0:11:51
0:06:40 0:15:06
0:04:48 0:06:16
0:06:09 0:11:49
0:05:14 0:05:14
0:02:22 0:05:30
0:04:12 0:07:13
Time
Prey
Swallow to
a
a
0:00:28
a
p
0:00:31
a
p
0:01:28
a
a
0:00:34
r
a
p
0:01:16
a
a
0:01:10
a
a
0:02:53
a
a
0:00:30
l
a
p
0:02:56
l
a
p
0:01:52
r
a
a
0:01:56
r
a
a
0:04:44
l
a
a
0:03:01
r
d
a
0:05:40
l
d
a
0:07:02
l
d
a
0:00:37
r
d
a
0:04:12
entire body
0 retracted
0 did not
0 did not
Body
Dorsal portion
Rotated prey Strikes Retracted
or
used for
or rotated
Prior to prey/did
ventral constriction around prey capture not
0 retracted
0 retracted
0 retracted
1 retracted
d to a
rotated prey
0 retracted
0 retracted
1 did not
1 did not
2 retracted
0 retracted
0 retracted
0 did not
0 did not
0 did not
2 did not
1st 1/3
0 did not
0 did not
APPENDIX A
Snake Snake
#6 mass
Week
#1
4
2
3.7
3
3.6
4
3.6
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
Monthly
Measurements
Girth
(CM)
Shed Date
Time to
Body
Retracted
begin
Prey
Time Time Total
Dorsal portion
Prey
Prey prey
Capture handling
Prey
Swallow to
to
feeding or
used for
or rotated
Prior to not
characteristic mass handling position method Handedness condition position subdue ingest duration ventral constriction around prey capture retract
pinkie
1.4
pinkie
1.2
pinkie
1.2
pinkie
1.2
APPENDIX A
91
92
6/28/2010
7/26/2010
8/23/2010
9/20/2010
10/18/2010
11/15/2010
30.2
33.5
42.6
46.7
50.7
53.6
2.3
2.6
3.0
3.2
3.8
4.0
Girth
(CM)
Prey
Capture handling
position method
a
ss
m
hl
a
ss
a
ss
m
c
m
p
a
ss
a
c
a
c
a
c
p
c
m
c
a
c
a
c
a
c
a
c
a
c
a
c
a
c
a
c
a
c
a
c
Monthly
Measurements
Snake Snake Prey
Prey
#7 mass characteristic mass
Week #1
5.6 pinkie
1.5
2
6.7 pinkie
2.0
3
7.4 pinkie
1.5
4
7.7 pinkie
2.0
5
8.8 pinkie
2.4
6
9.6 pinkie
2.0
7
9.8 pinkie
2.2
8 10.2 fuzzie
3.6
9 12.2 fuzzie
3.9
10 15.1 fuzzie
5.0
11 15.7 fuzzie
3.8
12 17.1 crawler
6.7
13 21.9 crawler
7.8
14 23.0 fuzzie
5.3
15 25.6 crawler
6.4
16 30.0 crawler
6.1
17 30.3 hopper
10.7
18 35.6 hopper
8.4
19 38.9 hopper
11.3
20 47.1 hopper
9.5
21 49.1 hopper
10.0
22 51.0 juv. mouse
14.9
Time to
begin
prey
handling
0:25:07
0:01:01
0:01:17
0:00:49
0:02:07
0:00:30
0:00:13
0:00:07
0:00:11
0:00:08
0:00:10
0:00:05
0:00:04
0:00:11
0:00:08
0:00:44
0:00:13
0:00:17
0:04:55
0:00:17
0:00:22
0:00:37
6/23/2010
8/9/2010
9/1/2010
9/25/2010
10/17/2010
Shed Date
Time
Prey
Swallow to
a
a
0:00:18
l
a
p
0:00:30
a
a
0:00:23
a
a
0:00:25
l
d
a
0:14:18
a
a
0:00:42
a
a
0:00:22
l
d
a
0:04:25
l
d
a
0:09:57
l
d
a
0:04:05
l
d
a
0:06:02
l
d
a
0:12:26
l
d
a
0:02:35
r
a
a
0:01:29
r
d
a
0:06:03
l
d
a
0:00:15
l
d
a
0:05:22
l
d
a
0:02:28
r
d
a
0:01:00
l
d
a
0:02:26
r
d
a
0:01:10
l
d
a
0:03:23
Time Total
to
feeding
ingest duration
0:06:33 0:31:58
0:13:13 0:14:44
0:04:00 0:05:40
0:05:21 0:06:35
0:06:41 0:23:06
0:03:02 0:04:14
0:04:26 0:05:01
0:05:12 0:09:54
0:07:46 0:18:24
0:04:55 0:09:08
0:05:02 0:11:14
0:10:55 0:23:26
0:14:01 0:16:40
0:06:10 0:07:50
0:16:30 0:22:42
0:16:15 0:17:16
0:09:30 0:15:05
0:06:05 0:08:50
0:06:15 0:12:10
0:05:58 0:08:38
0:07:36 0:09:18
0:12:17 0:16:17
Body
Retracted
Dorsal portion
or
used for
or rotated
Prior to not
0 retracted
v to a
1 retracted
1 retracted
1 retracted
d to a
rotated around
2 retracted
1 retracted
1 retracted
d to a
rotated around
0 retracted
1st 2/3 body rotated prey
1 retracted
1st 2/3 body
0 retracted
1st 2/3 body
1 did not
0 did not
0 retracted
0 did not
0 did not
0 retracted
1 did not
0 did not
0 did not
0 did not
0 did not
1st 1/3
0 did not
APPENDIX A
Snake Snake
#8 mass
Week #1
4.1
2
4.7
3
5.2
4
5.9
5
6.5
6
7.5
7
7.7
8
8.6
9
9.4
10 10.0
11 11.2
12 13.0
13 14.6
14 17.2
15 19.0
16 21.0
17 22.5
18 29.8
19 31.9
20 35.2
21 40.8
22 42.3
93
Prey
mass
1.6
1.6
1.9
1.7
1.6
2.2
2.5
2.2
2.2
2.3
4.3
3.6
5.3
4.7
5.3
4.8
8.7
10.8
7.0
10.4
13.3
10.0
7/5/2010
8/2/2010
8/30/2010
9/27/2010
10/25/2010
11/22/2010
28.1
32.8
37.2
42.1
48.5
51.1
2.1
2.4
2.5
2.7
3.4
3.8
Girth
(CM)
Prey
Capture handling
position method
a
ss
p
ss
m
ss
p
c
m
ss
m
c
a
p
m
c
m
ss
a
ss
a
c
a
hl
a
c
a
c
m
c
a
c
p
c
p
c
m
c
p
c
p
c
a
c
Monthly
Measurements
Prey
characteristic
pinkie
pinkie
pinkie
pinkie
pinkie
pinkie
pinkie
fuzzie
fuzzie
fuzzie
fuzzie
crawler
crawler
fuzzie
crawler
crawler
hopper
hopper
hopper
hopper
hopper
juv. mouse
Time to
begin
prey
handling
0:00:42
0:00:19
0:00:08
0:00:08
0:00:08
0:00:26
0:00:12
0:00:04
0:00:51
0:00:06
0:00:15
0:00:05
0:00:02
0:00:05
0:00:04
0:00:03
0:00:01
0:10:12
0:00:04
0:00:24
0:01:12
0:00:05
7/2/2010
8/16/2010
9/18/2010
10/10/2010
11/7/2010
11/28/2010
Shed Date
Time
Prey
Swallow to
a
a
0:00:43
a
p
0:00:46
a
p
0:00:47
r
d
a
0:01:59
a
p
0:00:38
l
d
a
0:01:31
a
a
0:00:59
l
a
p
0:00:04
a
p
0:01:23
a
a
0:00:23
r
a
a
0:00:49
l
a
a
0:00:39
l
d
a
0:04:50
r
d
a
0:09:46
r
d
a
0:02:56
r
d
a
0:01:58
l
d
a
0:06:16
l
d
a
0:02:38
r
d
a
0:01:08
l
d
a
0:04:16
r
d
a
0:06:03
r
d
a
0:02:18
Time Total
to
feeding
ingest duration
0:10:58 0:12:23
0:06:15 0:07:20
0:09:08 0:10:03
0:04:40 0:07:07
0:05:05 0:05:51
0:15:18 0:17:15
0:05:44 0:06:55
0:02:58 0:05:53
0:03:39 0:05:53
0:03:11 0:03:40
0:09:21 0:10:25
0:05:46 0:06:30
0:09:47 0:14:05
0:08:32 0:18:19
0:04:54 0:07:54
0:04:36 0:06:37
0:06:23 0:12:40
0:05:06 0:17:56
0:07:13 0:08:25
0:13:21 0:17:01
0:11:12 0:12:24
0:07:36 0:09:57
d to a
d to a
1st 1/3
1st 1/3
mid 1/3
Strikes Retracted
Prior prey/did
to
not
captur retract
5 retracted
0 retracted
0 retracted
rotated around
0 retracted
0 retracted
rotated around
0 retracted
0 retracted
rotated prey
0 did not
0 retracted
0 retracted
1 retracted
0 retracted
0 retracted
0 retracted
0 retracted
1 retracted
0 did not
1 did not
2 did not
0 did not
10 did not
0 did not
Body
Dorsal portion
Rotated prey
or
used for
or rotated
ventral constriction around prey
APPENDIX A
94
6/28/2010
7/26/2010
8/23/2010
9/20/2010
10/18/2010
11/15/2010
33.2
36.3
36.4
38.0
41.4
42.3
Monthly
Measurements
2.1
2.7
2.4
2.1
2.4
2.6
Girth
(CM)
Time to
begin
Prey
Snake Snake Prey
Prey prey
Capture handling
#9 mass characteristic mass handling position method Handedness
Week #1
4.1
2
4.7 pinkie
1.7 0:00:55 m
c
r
3
5.2 pinkie
2.1 0:06:01 a
ss
4
5.9 pinkie
2.0 0:01:29 m
ss
5
6.5 pinkie
2.5 0:02:58 a
ss
6
7.5 pinkie
2.0 0:01:16 a
ss
7
7.7 pinkie
2.3 0:12:46 a
ss
8
8.6
9
9.4 pinkie
2.2 0:04:49 a
ss
10 10.0
11 11.2
12 13.0
13 14.6 fuzzie
3.6 0:01:22 a
c
l
14 17.2 pinkie
2.6 0:00:39 a
ss
15 19.0
16 21.0
17 22.5
18 29.8 pinkie
2.9 0:37:12 p
c
r
19 31.9
20 35.2
21 40.8
22 42.3 fuzzie
3.5 0:16:12 a
ss
6/25/2010
8/9/2010
9/5/2010
10/7/2010
11/15/2010
Shed Date
a
d
a
a
a
a
a
a
a
d
a
a
a
a
a
a
a
a
a
a
a
a
0:07:10
0:03:01
0:02:45
0:05:44
0:02:30
0:02:44
0:00:49 0:03:15
0:13:00 0:08:00
0:00:59 0:05:41
0:00:02 0:04:49
0:00:30 0:02:40
0:40:31
0:00:58
0:00:14
0:00:07
0:00:26
0:00:17
0:20:16
0:58:12
0:08:02
0:05:30
0:07:59
0:48:36 d to a
0:10:00
0:04:28
0:08:49
0:04:12
0:15:47
entire body
rotated around
retracted
retracted
retracted
retracted
retracted
retracted
0 retracted
2 retracted
1 retracted
0 retracted
0 retracted
4
4
0
7
0
8
Body
Retracted
Time Time Total
Dorsal portion
Prey
Swallow to
to
feeding or
used for
or rotated
Prior to not
condition position subdue ingest duration ventral constriction around prey capture retract
APPENDIX A
Snake
#10
Week #1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
95
6/29/2010
7/27/2010
8/24/2010
9/21/2010
10/19/2010
11/23/2010
26.2
29.7
33.0
39.4
41.3
42.7
Monthly
Measurements
1.9
2.2
2.5
2.9
3.6
4.1
Girth
(CM)
Time to
begin
Prey
Snake Prey
Prey prey
Capture handling
mass characteristic mass handling position method Handedness
4.0 pinkie
2.4 0:03:25 a
c
r
5.4
5.1
5.0 pinkie
2.6 0:07:01 a
c
r
6.8
6.0
5.7 fuzzie
3.1 0:17:44 p
c
r
7.9 fuzzie
4.0 0:32:49 a
c
9.3 fuzzie
5.1 0:08:13 a
c
r
12.9
11.2
10.6 fuzzie
5.7 0:06:49 a
c
l
15.1 hopper
8.6 0:03:56 a
c
r
19.7
17.5 hopper
8.6 0:06:34 a
c
r
21.9 hopper
10.0 0:12:50 p
c
r
26.6 hopper
11.0 0:37:01 p
c
r
33.2
30.2 juv. mouse
17.3 0:04:25 a
c
r
40.2 adult mouse
20.0 0:06:12 a
c
r
44.2
43.1
6/24/2010
7/3/2010
9/4/2010
10/13/2010
11/29/2010
Shed Date
a
a
d
d
a
a
d
d
a
a
a
a
a
a
a
a
d
d
d
d
a
a
0:01:43 0:23:04
0:01:01 0:11:05
0:01:01 0:15:55
0:02:04 0:10:56
0:04:22 0:12:40
0:06:20 0:11:43
0:01:02 0:14:24
0:04:50 0:14:41
0:01:12 0:12:30
0:02:01 0:16:57
0:29:12
0:53:04
0:23:30
0:25:00
0:54:03
0:24:52
0:21:12
0:37:15
1:48:52
0:27:11
0:21:17
Time Total
to
feeding
ingest duration
0:26:05 0:33:33
0:01:11 0:13:05
Time
Prey
Swallow to
condition position subdue
a
a
0:02:53
Dorsal
or
ventral
d to a
entire body
back 2/3
entire body
1st 2/3
Body
portion
used for
constriction
1st 2/3
rotated prey
0 did not
0 did not
0 did not
0 did not
0 did not
0 did not
0 did not
0 did not
4 did not
0 did not
0 retracted
Retracted
or rotated
Prior to not
around prey capture retract
rotated prey
2 did not
APPENDIX A
96
7/6/2010
8/3/2010
9/31/2010
9/28/2010
29.9
36.5
43.9
52.8
Monthly
Measurements
1.9
2.3
3.2
4.0
Girth
(CM)
Time to
begin
Prey
Snake Snake Prey
Prey prey
Capture handling
Week
#1
4 pinkie
2.2 0:01:29 a
ss
2
5.5 pinkie
2.3 0:00:22 m
c
l
3
6 fuzzie
3.6 0:00:09 m
c
l
4
7.9 fuzzie
4.5 0:00:31 m
c
l
5
9.2 fuzzie
4.6 0:00:17 a
ss
6 11.4 fuzzie
5 0:02:14 a
c
l
7 13.6 fuzzie
5.9 0:00:26 a
c
l
8 18.2 crawler
7.5 0:00:29 a
c
l
9 20.6 hopper
10 0:00:54 a
c
r
10
26 hopper
11.6 0:00:08 a
c
r
11 31.9 juv. mouse
13.1
r
12 26.7 juv. mouse
13.3 0:00:12 a
c
l and r
13 33.6 juv. mouse
15.2
14
32 juv. mouse
13.2
15
31 juv. mouse
12.8
16 30.1 juv. mouse
10.7
17
18
19
20
21
22
a
d
6/30/2010
8/18/2010
9/15/2010
10/18/2010
Shed Date
a
p
a
a
a
a
a
a
a
a
a
a
d
d
a
d
d
d
d
d
0:17:58
0:11:04
0:14:05
0:40:13
0:12:38
0:15:44
0:16:57
0:19:11
0:19:07
0:41:06
0:03:11 0:18:04
0:01:23
0:05:48
0:15:23
0:06:41
0:00:35
0:06:42
0:02:34
0:02:31
0:06:16
0:06:02
0:21:19
0:18:50
0:17:14 d to a
0:29:28
0:47:25
0:13:30
0:24:40 d to a,p
0:19:57
0:22:12
0:26:17
0:47:16
rotated
rotated
rotated
rotated around
1st 2/3
entire body
entire body
entire body
1st 2/3
1st 2/3
retracted
did not
did not
did not
did not
did not
retracted
retracted
did not
did not
0 did not
0
0
1
0
0
0
2
0
1
0
Body
Retracted
Time Time Total
Dorsal portion
Prey
Swallow to
to
feeding or
used for
or rotated
Prior to not
APPENDIX A
97
c
c
c
0:04:48 a
0:02:50 m
0:18:12 a
ss
c
ss
0:04:18 a
0:11:45 a
0:04:08 a
c
ss
0:02:06 a
0:01:10 a
ss
0:05:58 a
7/6/2010
8/3/2010
8/31/2010
9/28/2010
10/26/2010
11/23/2010
28.1
33.2
36.3
45.2
47.1
48.9
1.8
2.0
2.1
2.7
2.8
2.8
Girth
(CM)
r
l
l
r
r
7/5/2010
8/3/2010
9/22/2010
10/13/2010
11/3/2010
Shed Date
d
d
d
d
a
d
a
a
a
Prey
Capture handling
Prey
position method Handedness condition
a
ss
a
a
ss
a
Monthly
Measurements
Snake Snake Prey
Prey
Week #1
3.9 pinkie
2.1
2
4.9 pinkie
2.2
3
5.7
4
5.6 pinkie
2.3
5
6.3
0.0
6
5.8 fuzzie
3.4
7
8.6
8
7.7 fuzzie
4.4
9 10.0 fuzzie
5.1
10 11.7 fuzzie
5.0
11 14.5
12 12.9 fuzzie
6.0
13 16.0
14 15.7
15 15.0 hopper
8.6
16 20.7
17 18.8 hopper
9.0
18 24.5 juv. mouse
12.7
19 29.1
20 25.7
21 25.7
22 25.0
Time to
begin
prey
handling
0:02:11
0:05:33
a
a
a
a
a
a
a
a
a
0:02:40 0:15:42
0:02:03 0:17:04
0:02:15 0:25:05
0:03:10 0:14:01
0:00:41 0:16:11
0:00:33 0:19:03
0:00:31 0:12:51
0:01:05 0:25:58
0:21:12
0:37:19
0:28:30
0:21:59
0:21:10
0:31:19
0:17:30
0:25:09
0:13:57
1st 2/3
entire body
0 did not
0 did not
0 did not
0 did not
0 retracted
0 did not
0 retracted
1 retracted
0 retracted
Body
Retracted
Time Total
Dorsal portion
to
feeding or
used for
or rotated
Prior to not
0:30:26 1:02:21
0 retracted
0:10:07 0:17:45
0 did not
0:00:40 0:07:19
Time
Swallow to
position subdue
a
0:30:36
a
0:02:05
APPENDIX A
98
7/6/2010
8/3/2010
8/31/2010
9/28/2010
10/26/2010
11/23/2010
27.3
33.0
34.7
38.4
43.6
46.2
Monthly
Measurements
2.1
2.3
2.4
2.5
2.7
2.9
Girth
(CM)
Time to
begin
Prey
Snake Snake Prey
Prey prey
Capture handling
Week #1
3.9
2
3.9 pinkie
2.0 0:03:01 m
p
3
4.9 pinkie
2.1 0:00:54 a
p
4
5.3 pinkie
2.2 0:00:29 p
c
l
5
6.0 pinkie
2.5 0:01:35 a
c
l
6
7.3
7
6.8 fuzzie
3.4 0:01:00 m
c
l
8
8.4
9
7.9 fuzzie
4.5 0:01:05 m
c
l
10 11.1
11 10.3
12
9.5
13
9.3 fuzzie
4.6 0:00:23 p
c
l
14 12.4
15 13.6
16 13.6 crawler
6.3 0:00:25 p
c
l
17 16.2 hopper
9.0 0:01:05 a
c
r
18 22.5
19 19.8 hopper
8.7 0:00:24 a
c
l
20 24.1 hopper
9.6 0:00:13 p
c
r
21 27.7
22 27.1
6/30/2010
8/14/2010
9/11/2010
10/19/2010
11/7/2010
Shed Date
a
a
a
d
d
d
a
d
a
a
a
a
d
d
p
a
a
a
a
a
a
a
0:20:18
0:07:35
0:06:12
0:05:01
0:09:36 0:10:00
0:07:00 0:10:00
0:11:05 0:20:12
0:05:50 0:17:50
0:00:16 0:05:13
0:01:42 0:08:30
0:01:12 0:12:06
0:02:23
0:02:27
0:03:08
0:02:20
0:20:00
0:17:15
0:31:42
0:24:45
0:20:21
0:11:17
0:15:18
0:25:42
0:10:56
0:09:49
0:09:04
entire body
entire body
entire body
rotated prey
rotated prey
retracted
did not
retracted
retracted
0 did not
0 did not
0 did not
0 did not
0 did not
0 did not
0 did not
0
1
3
4
Body
Retracted
Time Time Total
Dorsal portion
Prey
Swallow to
to
feeding or
used for
or rotated
Prior to not
APPENDIX A
99
c
c
c
c
0:01:46 a
0:00:57 a
0:02:57 m
0:01:42 a
7/6/2010
8/3/2010
8/31/2010
9/28/2010
10/26/2010
30.5
33.6
41.4
47.0
56.2
2.0
2.2
2.6
3.3
3.6
Girth
(CM)
Prey
Capture handling
position method
a
ss
m
c
a
ss
a
ss
a
ss
a
c
a
c
Monthly
Measurements
Snake Snake Prey
Prey
Week
#1
3.9 pinkie
2.2
2
5.2 pinkie
2.2
3
2.8 pinkie
2.6
4
6.5 pinkie
2.9
5
8.2 fuzzie
4.1
6 10.1 fuzzie
4.8
7 11.5 fuzzie
5.7
8 14.9
9 13.1 crawler
6.7
10 17.8 hopper
8.6
11 21.6
12 21.4 hopper
10
13 25.1
14 24.1 juv. mouse
12.7
15 32.5
16 28.6
17 28.6
18 28.6
19
20
21
22
Time to
begin
prey
handlin
0:03:14
0:01:13
0:00:14
0:01:09
0:01:23
0:00:17
0:01:12
r
l
r
r
7/6/2010
8/3/2010
8/30/2010
9/21/2010
Shed Date
d
d
d
d
a
a
a
a
0:15:32 0:14:56
0:02:57 0:13:23
0:31:10
0:19:59
0:17:04
0:21:12
Time Total
to
feeding
ingest duration
0:17:49 0:22:28
0:09:28 0:15:52
0:10:29 0:12:06
0:09:07 0:11:40
0:39:27 0:44:00
0:10:14 0:16:01
0:11:50 0:16:40
0:02:07 0:13:11
0:01:42 0:18:31
Time
Prey
Swallow to
a
a
0:01:25
r
d
a
0:01:11
a
a
0:01:23
a
a
0:01:24
a
a
0:03:10
l
a
a
0:05:30
r
a
a
0:04:38
entire body
1st 2/3
1st 2/3
2 retracted
0 retracted
0 retracted
0 retracted
Body
Retracted
Dorsal portion
or
used for
or rotated
Prior to not
1 retracted
1st 2/3
0 did not
0 retracted
0 did not
1 retracted
d to a mid 1/3
0 did not
1st 2/3
rotated
0 did not
APPENDIX A
Snake Snake
#15 mass
Week
#1
4.1
2
4.0
3
3.8
4
3.8
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
Monthly
Measurements
Girth
(CM)
Shed Date
Time to
Body
Retracted
begin
Prey
Time Time Total
Dorsal portion
Prey
Prey prey
Capture handling
Prey
Swallow to
to
feeding or
used for
or rotated
Prior to not
characteristic mass handling position method Handedness condition position subdue ingest duration ventral constriction around prey capture retract
pinkie
2.4
pinkie
2.2
pinkie
1.9
pinkie
2.2
APPENDIX A
100
101
7/6/2010
8/3/2010
8/31/2010
27.1
34.5
37.7
Monthly
Measurements
Time to
begin
Snake Snake Prey
Prey prey
Capture
#16 mass characteristic mass handling position
Week
#1
4.1 pinkie
2.3 0:02:01 a
2
5.4 pinkie
2.3 0:02:16 p
3
6.0 pinkie
2.6 0:00:45 a
4
6.9 fuzzie
3.5 0:00:24 a
5
9.0
6
7.9 fuzzie
4.2 0:01:36 a
7 10.1 fuzzie
5.4 0:02:16 a
8 14.0
9 12.5
10 11.6
11 11.5
12
13
14
15
16
17
18
19
20
21
22
2.0
2.8
3.1
Girth
(CM)
a
a
ss
ss
7/2/2010
8/12/2010
9/6/2010
Shed Date
a
a
Swallow
position
a
p
p
a
Prey
handling
Prey
method Handedness condition
ss
a
ss
a
ss
a
ss
a
0:12:10
0:13:13
1 retracted
2 retracted
Body
Retracted
Time Total
Dorsal portion
to
feeding or
used for
or rotated
Prior to not
0:17:27 0:19:28
13 retracted
0:12:40 0:14:56
0 retracted
0:08:36 0:09:21
3 retracted
0:12:18 0:12:42
4 retracted
0:00:29 0:10:05
0:01:43 0:01:35
Time
to
subdue
0:02:01
0:02:16
0:00:45
0:00:24
APPENDIX A
Snake Snake
#17 mass
Week #1
5.1
2
6.7
3
9.7
4 10.6
5 12.3
6 16.0
7 14.3
8 16.9
9 21.6
10 23.8
11 32.3
12 38.2
13 35.0
14 44.0
15 42.2
16 42.2
17 51.4
18 47.9
19 66.3
20 55.8
21 55.3
22 70.1
102
21.3
23.4
adult
adult
p
a
a
m
p
0:00:12 a
0:00:56 a
0:00:51 a
0:01:24 a
0:01:39
0:00:26
0:00:01
0:00:01
0:00:03
6/29/2010
7/27/2010
8/24/2010
9/21/2010
10/19/2010
11/16/2010
32.0
37.8
46.8
57.3
58.2
61.2
c
c
c
c
c
c
c
c
c
2.2
2.9
3.5
3.4
4.4
4.2
Girth
(CM)
Prey
Capture handling
position method
a
ss
a
c
p
c
a
hl
a
c
Monthly
Measurements
20.2
16.3
juv. mouse
adult
5.9
8.1
9.0
12.8
14.3
fuzzie
hopper
hopper
juv. mouse
juv. mouse
Prey
Prey
characteristic mass
pinkie
2.8
fuzzie
3.9
fuzzie
5.7
fuzzie
4.5
fuzzie
5.3
Time to
begin
prey
handling
0:01:11
0:00:07
0:01:37
0:00:42
0:01:07
r
r
r
l
l
r
l
l
l
6/28/2010
7/20/2010
8/7/2010
8/30/2010
9/21/2010
10/12/2010
11/7/2010
Shed Date
d
d
d
d
d
d
d
d
d
a
a
a
a
a
a
a
a
a
0:13:01
0:22:14
0:17:09
0:19:11
0:15:32
0:02:04 0:14:01
0:01:21 0:14:54
0:02:16 0:29:12
0:16:17
0:17:11
0:32:19
0:20:00
0:15:49
0:26:30
0:19:12
0:21:30
0:17:14
entire body
entire body
entire body
back 2/3
entire body
did not
did not
did not
did not
did not
0 did not
0 did not
0 did not
0 did not
0
1
3
2
0
Body
Retracted
Time Total
Dorsal portion
to
feeding or
used for
or rotated
Prior to not
0:19:16 0:20:54
0:27:29 0:28:47
entire body
0 retracted
1:18:05 1:22:49
1st 2/3
0 retracted
0:12:33 0:17:45
mid 1/3
0 retracted
0:16:04 0:21:12
1st 1/3
0 retracted
0:03:30 0:15:06
0:01:09
0:03:50
0:02:01
0:02:19
0:01:39
Time
Prey
Swallow to
a
a
0:00:17
l
d
a
0:01:11
l
d
a
0:03:07
r
d
a
0:04:30
l
d
a
0:04:01
APPENDIX A
Snake Snake
#18 mass
Week #1
5.6
2
7.7
3 10.8
4 12.4
5 14.3
6 19.3
7 17.3
8 20.4
9 23.6
10 31.6
11 27.6
12 35.0
13 43.5
14 38.8
15 47.1
16 43.4
17 58.1
18 53.7
19 65.1
20 61.6
21 61.4
22 61.3
103
13.1
14.7
17.1
20.0
23.0
juv. mouse
juv. mouse
juv. mouse
adult
adult
0:01:49 a
0:02:30 a
0:05:50 a
0:01:14 m
0:08:40 a
0:00:13 p
0:00:10 p
0:00:08 p
6/29/2010
7/27/2010
8/24/2010
9/21/2010
10/19/2010
11/16/2010
34.7
41.0
48.7
60.9
62.6
64.7
c
c
c
c
c
c
c
c
2.1
2.9
3.3
4.4
4.4
4.2
Girth
(CM)
Prey
Capture handling
position method
m
ss
a
c
a
c
a
c
m
c
Monthly
Measurements
8.0
8.4
9.9
crawler
hopper
hopper
Prey
Prey
characteristic mass
pinkie
2.9
fuzzie
4.5
fuzzie
6.0
fuzzie
5.2
crawler
6.9
Time to
begin
prey
handling
0:00:08
0:00:12
0:00:19
0:00:10
0:02:22
l
r
l
l
r
l
l
l
8/24/2010
7/21/2010
8/8/2010
9/26/2010
10/25/2010
Shed Date
d
d
d
d
d
d
d
d
a
a
a
a
a
a
a
a
0:04:01 0:15:56
0:07:07 0:15:05
0:01:50 0:09:30
0:03:03 0:15:13
0:02:40 0:10:59
0:20:46
0:24:42
0:17:10
0:19:30
0:22:18
0:15:09
0:17:41
0:19:13
entire body
entire body
entire body
1st 2/3
entire body
1 did not
0 did not
0 did not
0 did not
4 did not
0 did not
0 did not
0 did not
Body
Retracted
Time Total
Dorsal portion
to
feeding or
used for
or rotated
Prior to not
0:16:50 0:18:00
1 retracted
0:21:08 0:26:28
1st 1/3
5 did not
0:38:45 0:40:00
1st 2/3
1 did not
0:14:26 0:16:24
2 did not
0:15:23 0:21:04
1st 2/3
0 did not
0:05:13 0:09:43
0:00:32 0:16:59
0:02:04 0:07:01
Time
Prey
Swallow to
a
a
0:01:02
r
a
a
0:05:08
l
d
a
0:00:56
l
d
a
0:01:48
l
d
a
0:03:19
APPENDIX A
APPENDIX B
IACUC PROTOCOL
IACUC USE ONLY
PROTOCOL FOR ANIMAL USE AND CARE
E-mail to: [email protected]
Please use a minimum font size of 10
1. Contacts:
Investigator
Last Name:
Cairns
First:
Stefan
E-mail:
Department/
Affiliation:
Alternate Contact
Last Name:
First :
MI:
E-mail:
[email protected]
Department of Biology: WCM 319A,
UCM
Phone / after hrs:
2. Title
PROTOCOL: 10-3212
EXPIRES: 6-25-13
Department/
Affiliation:
Penning
David
A
[email protected]
Department of Biology: Graduate Program
Phone / after hrs:
660-5438291
MI:
816-695-5420
816-695-5420
Functional Morphology and prey-handling behaviors of
hatchling “wild phase’ corn Snakes Pantherophis guttata
guttata
3. Species (common names):
Total number for study
Name of source of the animals:
Corn Snake (Pantherophis guttata guttata)
No more than 27
Myself (David Penning)
House Mouse (Mus musculus)
@ 700 (depending on
length of study and
total snakes used)
Myself (David Penning)
4. Procedures: Briefly describe the animal procedures included in this project using language for non-scientific personnel. This
page is posted on the animal room door for animal care staff and must be clear and understandable to the staff. There will be
additional space for a detailed experimental protocol.
Each corn snake is going to be housed in an individual cage measuring 11 by 11 by 6 inches. Each cage will have a substrate
of aspen bedding approximately 1/ 2 inch in depth. Water will be available at all times to each snake. The handling of the
snakes will be kept to a minimum throughout the study. The snakes will be kept in their cages at all times except during
scheduled cleaning where they will be moved into a temporary cage and then placed back in their original cage. Each snake
will be fed a weekly meal of a certain weight (depending on the feeding category they are in). Food for the snakes will be live
baby mice. All of their food will remain within the snake’s appropriate size for a regular feeding but the specific meal size will
vary within that range. The room where the snakes will be housed will be heated with a space heater that is controlled with a
rheostat (temperature controlling) at approximately 83˚F.
Mice will be brought in from an outside source and will not be at the university for more than 12 hours. Mice will be placed in
the snake cages and the behaviors of the snake will be observed. The feeding process that takes place will be between the
snake and mouse only. No other force will influence the feeding process. There will be no other interaction with the mice.
5. Animal
Location
Overnight housing
Study area / Laboratory (Room/Bldg.)
UCM animal facility
Animals will be maintained by:
Animal isolation room (TBD)
[ x ] Vivarium [ ] Investigator (If investigator maintained, please attach husbandry SOPs.)
104
6. Special Husbandry Requirements: Briefly describe any special food, water, temperature, humidity, light cycles, caging
type, and bedding requirements. Please include any special instructions for animal care staff with regard to procedures to follow
for disposal of dead animals and if pest control can be performed in the animal area.
For Corn Snakes
Food will be in the form of live mice only.
Temperature will be kept @83˚±2˚F. Temperatures can fluctuate around this.
Light cycle will be 12:12 for day and night light.
Caging will be 11 by 11 by 6 inches.
Bedding will be in the form of Aspen shavings only.
Any snake that dies will need to be frozen immediately upon discovery so that I can examine them.
It is not recommended to use pest control agents around these animals.
7. Hazardous Materials (If used specifically in this protocol, please fill out the Room/Lab Safety Information Sheet):
Infectious Agents?
[ ] Yes [ x ] No
Materi
al:
[ ] Lab
[ ] Vivarium
Radioisotopes?
[ ] Yes [ x ] No
Materi
al:
[ ] Lab
[ ] Vivarium
Chemical Carcinogens?
[ ] Yes [ x ] No
Materi
al:
[ ] Lab
[ ] Vivarium
Recombinant DNA?
[ ] Yes [x ] No
Materi
al:
[ ] Lab
[ ] Vivarium
Hazardous Chemicals?
[ ] Yes [x ] No
Materi
[ ] Lab
al:
Hazardous chemicals would include chemicals that are flammable, toxic, corrosive, or chemotherapeutic.
[ ] Vivarium
105
8. Funding and Funding Source
Is the protocol for newly funded NIH research?
Yes [ ] No [ x ]
Funding Source:
Willard North; self
**If this protocol is submitted for a newly funded NIH grant, please attach the relevant animal-related pages from
section D. Experimental Design and Methods and section F. Vertebrate Animals that will allow a direct comparison
between this protocol and the animal work proposed in your grant. This comparison of NIH grants and Animal Use and
Care protocols is required by PHS policy and only applies to newly funded NIH grants. Please contact IACUC staff if
you have questions associated with this requirement.
9. What Veterinarian or veterinary service will provide care for your animals?
Veterinarian:
Address:
Day phone:
Emergency
phone:
E-mail:
10. Objective and Significance:
Please provide a brief description of the objectives and significance of the study, bearing in mind your target audience may be
a faculty member from an unrelated discipline.
Objective:
This study has four goals throughout the entirety of the project. Some of the questions have been studied
for different snakes in the same genus (Panthrophis – formerly Elaphe) but none included the corn snake. Prey
handling of various prey sizes is the first and main goal to be studied in this project. This will be observed at every
feeding for every corn snake until the completion of the laboratory study.
The secondary goal of this study is to attempt to form a growth model for prey ingested (g) compared to
length (cm), girth (cm), and weight (g)at a constant temperature (˚F). Sheds from this project will be kept. This
may not be a factor in this study but it may be a very important source of data for a further project (Ball, 2004).
The third goal of this project is to determine growth of snakes when fed varying meal sizes. Many studies
have been done using multiple meals more frequently and smaller meals less often for growth comparisons. No
study has been found that compares growth in mutually exclusive categories that are fed only one meal size. This
data may give insight on energy expenditures needed to subdue larger prey. Energy expenditure data will be very
interesting because there is not much energy expenditure information out there besides the general rule that
ectotherms use more for food energy for growth and reproduction than endotherms. There are some rough
guidelines for species but there is not model of any kind for the corn snake.
The fourth goal of this project is to differentiate energy expenditures of various prey handling methods.
Various constriction patterns have been observed but there is currently no research that I have found that has
calculated the costs of the handling method the snake chooses. I have not found any research on this specific area
of study.
Significance: Please provide a statement of relevance to human or animal health, the advancement of knowledge, or the good of
society.
This study is unique because it asks questions for the scientific world as well as provides insight to the pet
trade industry in the form of new handling care observations, expected growth rates, and the best food size for
juvenile Panterhophis guttata guttata. The corn snake industry is easily a million dollar industry every year so this
information could yield very important results. No other snakes are bred as frequently and are as popular as corn
snakes (Love, 2005; Soderberg, 2006). This information will be greatly appreciated in the herpitocultural world.
Observing prey handling methods and growth rates (weight, length, and girth) will help to ensure the healthiest
snakes possible which will in turn make better pet care and understanding of the corn snakes growth and response
to food.
With exact food ingestion data along with weight, length, and girth or the snake it will be possible to
estimate a snakes age and/or amount of meals ingested to reach its current size. This could give further insight into
the effect a snake has on the ecosystem. This may also give some insight to the effects of invasive snakes on an
environment by calculating expected growth and consumption rates.
106
11. Literature search for alternatives and unnecessary duplication: Federal law specifically requires this section.
Alternatives should be considered for any aspect of this protocol that may cause more than momentary or slight pain or distress
to the animals. Alternatives to be considered include those that would: 1) refine the procedure to minimize discomfort that the
animal(s) may experience; 2) reduce the number of animals used overall; or 3) replace animals with non animal alternatives.
**
a) Databases: List a minimum of two databases searched and/or other sources consulted. Include the years covered by the
search. The literature search must have been performed within the last six months.
Database Name
Years Covered
Keywords / Search Strategy
Date
Bioone
1999 to present
Prey handling behavior
4/1/10 to
4/21/10
Jstor
1995 to 2005
Feeding captive snakes
4/1/10 to
4/21/10
b) Result of search for alternatives: Please comment on the application(s) of any identified alternatives, including how these
alternatives may be or may not be incorporated to modify a procedure to either lessen or eliminate potential pain and distress.
The first study (“Prey handling behavior of hatchling Elaphe helena”) I referenced used sixty snakes in three groups of twenty
instead of the groups that I am going to use (three groups of nine each). No snake is going to undergo any undue stress.
The second search was for variations of food types for this study (“methods of feeding captive snakes”). I would not be able to
observe any prey handling behaviors on frozen/thawed mice but I would be able to measure growth of snakes when given
differing meal sizes. The energy expenditure of constricting and consuming varying live food items would not be able to be
studied. This is a major part of my project. There would be no live mice used in the study but there would be a lot less
information available for me to test. The snakes would not be constricting or using any type of different prey handling methods
so there would be no information available for me to look at on this topic.
c) Animal numbers justification: Please describe the consideration given to reducing the number of animals required for this
study; this could include any in vitro studies performed prior to the proposed animal studies. Please also provide information on
how you arrived at the number of animals required. If preliminary data is available and if relevant, please provide a power
analysis or other statistical method used to determine the number of animals necessary. For studies where a statistical method
such as a power analysis is not appropriate (such as pilot studies, tissue collection), please provide a brief narrative describing
how the requested animal numbers were determined to be necessary.
A lot of studies that I have read have had a sample size of twenty or larger. A lot of studies have been done with smaller
quantities as well. I am attempting to use a total of 27 corn snake for the project with 9 being in each of the three categories. A
sample size of 27 is a sufficient number of animals that will help to eliminate error from biological variation. My study is going to
use a smaller amount of animals than what most of the other studies I found used. It is unlikely that I will have access to a
larger sample than this.
d) Species rationale: Please provide the rationale for the species chosen, and any consideration given to the use of nonmammalian or invertebrate species, or the use of non-animal systems (e.g., cell or tissue culture, computerized models).
107
I chose to use the corn snake because I breed these snakes and therefore will have a much lower budget cost. Without my
personal breeding I would not be able to afford the cost of this project.
e) Has this study been previously conducted?
[ ] Yes [ x] No
If the study has been previously conducted, please provide scientific justification for why it is necessary to repeat the experiment.
Variations of this study have been done with different species of snakes but no study has addressed the
exact questions that I am asking with the corn snake specifically.
12. Summary of Procedures:
a)
Describe the use of animals in your project in detail. Using terminology that will be understood by individuals
outside your field of expertise. Please write a detailed description of all animal procedures in a logical progression,
beginning with receipt of the animals and ending with euthanasia or the study endpoint. List each study group and
describe all the specific procedures that will be performed on each animal in each study group.
Please provide a complete description of the surgical procedure(s) including Anesthesia, Analgesia, and/or
Neuromuscular blocking agents. If the procedure(s) will be performed by vivarium or veterinary staff with an
established, IACUC-approved SOP, please identify the SOP title and number.
Field Studies: If animals in the wild will be used, describe how they will be observed, any interactions with the animals,
whether the animals will be disturbed or affected, and any special procedures anticipated. Indicate if Federal or State
permits are required and whether they have been obtained.
This cell will expand, but please try to be concise. Please define all abbreviations.
I. BREEDING, HATCHING, AND RANDOMIZATION
The snakes will be coming from my personal collection. Adults began brumation (winter
shut down) on December 4th, 2010. Males and females were introduced to one another on
February 10th, 2010. Each caging systems heating units will be turned on February 20th. In
the wild, corn snakes breed from March to May, lay eggs in May through July, and eggs hatch
July through September (Behler et al, 2000). The breeding season starts a few weeks early
due to previous annual breeding of some of my adult breeding stock. This will get a close
approximation of egg laying and hatching. Eggs are expected to hatch in mid to late August if
this season is similar to the previous last season. Genetic history will be recorded for the
purpose of comparing genetics as a possible variable of error and for my personal use once
the study has been completed. Male breeders will be kept to a minimum in order to keep
genetic variation as minute as possible. Large sample size will also help to eliminate possible
error caused by genetic variation.
All snake eggs will be incubated in the same type of incubators (Little Giant® Still Air
Incubator) with the same average temperature and humidity. Humidity will be monitored
daily and all incubators will be in the same room exposed to similar temperature fluctuations.
It is highly unlikely that all snakes will hatch on the same day and then shed their first skin on
108
the same day as well. Once snakes have hatched they will be placed in individual cages and
labeled with their clutch information, weight (g), and initial snout to vent length (cm) on their
lid. Snakes will be given small water dish and a thin layer of aspen bedding inside their
cages. Water will be available at all times (see “care and maintenance” for exact details on
caging and maintenance). Hatchlings will then be checked every Monday for their first shed.
Checking for sheds once a week will allow more snakes to enter the experiment at one time
rather than putting each one in on the exact day of their first shed. Checking once a week
should be a sufficiently narrow window so that there is no significant difference between
individual snakes energy level from lack of food consumption when entering the experiment.
The feeding trials will begin the following scheduled feeding day upon the discovery of their
first shed. All sheds will be kept, labeled, and stored appropriately for a future study. Any
feces will be cut out of the sheds before being stored. They are being kept due to the lack of
knowledge currently available on the differences between neonates first shed and the
following sheds (Ball, 2004).
Each clutch will be represented in each experimental category as equally as possible.
The order in which they are placed in each category will be through a random number
generator. The number will be random but once the proportion of the clutch is filled in the
appropriate category the number generator will be adjusted to the remaining experimental
categories only. For example(in a clutch of nine), if the number generator selects the third
group the first three times that group will then be omitted from the rest of the randomization
so that each clutch is equally distributed but the manner in which they enter the group remains
random.
II. CARE AND MAINTENANCE
The cage design is determined on what will work best for filming as well as space
efficiency and time maintenance for such a large sample. A better cage design consists of a
glass or wooden cage with sliding glass doors (Mattison, 2007). Each Panthrophis guttata
guttata will be caged individually in a cage internally measuring 11×11×6 inches. This cage
size is used because the cages will be able to use the glass pieces that were donated by Travis
Lyon. Cages measuring 19×13×11 inches for yearlings (Barnard et al, 1979) but a cage this
size is not necessary if the snake is kept under ideal conditions. Snakes do not necessarily
require large cages (Mattison, 2007). If snake species that hide during most of the day are
provided with all of their needs, they will normally be content to live in a cage that measures
less than their body length (Mattison, 2007). Corn snakes are great climbers and can be
arboreal in nature but are mostly found on the ground (Collins et. al., 1992; Knopf, 1988;
Mattison, 2007). Because the corn snakes will not need to escape predators or search for food
height in caging is not necessary. In addition to the above evidence, other studies have used
cages of similar size to house neonate snakes (Mehta, 2003, Mori, 1993, 96; Myer et al,
1973).
The smaller cages will drastically cut cost but will still provide plenty of space for corn
snakes that are one year of age or younger. Small cages are also easier to heat and more
economical to build than larger ones (Soderberg, 2006). A sliding, clear glass or plexi-glass
piece will be used for the lid so that filming can be done from overhead without disturbing the
snake or exposing it to other individuals. The lid will slide into a groove that is
approximately ¼ inch from the top of the enclosure. Multiple one eighth inch holes will be
drilled into the back of the cage for proper air exchange with a few in the front for cross
ventilation. This will allow ventilation without exposing each individual to the visual cues
from other snakes.
Aspen shavings will be used as a substrate because of its lack of dust, absorbent
capability, and lack of smell. Absorbent substrate is important because it helps to prevent
bacterial growth. Aspen shavings will be placed in each enclosure approximately ½ inch in
depth. This will allow the snake to burrow in times of stress. Water will be available to the
snake at all times in a plastic “party” cup that has been cut to fit each cage. Plastic party cups
are preferable because of the low cost for large quantities, the appropriate size for individual
cages, and the internal color of the cup. The inside color of the cup is white which allows for
faster identification of any ectoparasites in the bowl (Soderberg, 2006). This will help to
109
identify and prevent diseases. The heat for each snake will be provided by a space heater
controlled by a rheostat set at 83˚F to allow for proper food digestion. Heating the entire
room that all the snake cages are in is a common practice among many corn snake breeders
(Soderberg, 2006). Many experiments frequently keep snakes at or slightly above room
temperature without any individual heat sources (Mori, 1993, 96; Mehta, 2003; Smith et al,
1972). Each cage will be spot cleaned weekly and bedding will be changed as needed
(approximately at 2 to 3 month intervals). Prevent-a-might© will be sprayed in all cages if
any mites are found as a precautionary measure since so many snakes will be in such close
quarters and to expose all animals to the same conditions.
Cages will be located in the laboratories on the bottom floor of the Morris building at
UCM. Ambient air temperatures in the lab should fluctuate around 83°F. All cages will be
exposed to the same ambient air temperatures and fluctuations. Each cage will be placed on a
table next to another set of cages. Each cage will be approximately ½ inch higher than the
previous cage so that the lid can slide out over the previous cage. This will allow the cages to
be opened for feeding and maintenance without causing too much movement to the snake’s
environment before feeding.
Each snake will be put into a feeding schedule of one meal per week. Snakes will be fed
on Tuesday, Wednesday, and Thursday depending on their feeding category. Snakes that
refuse to eat on their scheduled feeding day will have the opportunity to try another meal the
day after their original scheduled day. This process will be repeated until the end of the
study. Snakes will be weighed the day before each feeding and the appropriate food size will
be recorded by weight to use for the following feeding day. The three feeding categories are
based on a mass ratio (MR) of mouse weight to snake weight. The small, medium, and large
categories represent a mass ratio of 20-35%, 36-46%, and 47-59% respectively. The mouse
will be placed in the cage and then the lid will be closed. Each feeding for each snake will be
recorded from right before feeding until the completion of the feeding process.
Additional information being recorded during each feeding trial are: time to begin prey
handling; capture position of prey; prey handling method; variation of constriction;
effectiveness of constriction; condition of prey before ingestion; swallowing position; overall
time to subdue prey; time to ingest prey; and total feeding duration.
I am estimating that this project will run for approximately six months. I will attempt to
run the project for as long as I have funding. Upon the completion of the study all snakes will
be returned to my personal collection.
b) Study Groups and Numbers Table: Define the numbers of animals to be used in each experimental group described
above. The table may be presented on a separate page as an attachment to this protocol if preferred. This table must account
for all animals proposed for use under this protocol.
Group
Procedures / Treatments
Number of Animals
1(small)
Snakes fed an MR category of 20-35% of their body mass
Sample ≤9
2(md)
Sample ≤9
3(lg)
Sample ≤9
110
c) Is death an endpoint in your experimental procedure?
[ ] Yes [x ] No
(Note: "Death as an endpoint" refers to acute toxicity testing, assessment of virulence of pathogens, neutralization tests for toxins, and
other studies in which animals are not euthanized, but die as a direct result of the experimental manipulation). If death is an endpoint,
explain why it is not possible to euthanize the animals at an earlier point in the study. If you can euthanize the animals at an earlier point,
based on defined clinical signs, then death is not an endpoint.
NA
d) Surgery: This project will involve: Survival surgery [ ] Yes [ x] No
Location:
Building:
NA
Name of the surgeon:
Room:
Terminal surgery [ ] Yes [ x ] No
NA
NA
e) This project will involve Multiple Major Surgical Procedures [ ] Yes [ x ] No
Please provide scientific justification for multiple major surgical procedures:
NA
f) Drugs to be used (except for euthanasia) - anesthetics, analgesics, tranquilizers, neuromuscular blocking
agents or antibiotics:
Post-procedural analgesics should be given whenever there is possibility of pain or discomfort that is more than slight or
momentary.
Provide the following information about any of these drugs that you intend to use in this project.
Species
Drug
Dose (mg/kg)
Route
When and how often will it be given?
NA
g) Anesthesia monitoring: Please complete the following:
Please identify the physiologic parameters monitored during the procedure to assess adequacy of anesthesia and when
additional anesthesia will be administered.
NA
h) Neuromuscular blocking agents can conceal inadequate anesthesia and, therefore, require special justification. If you
are using a neuromuscular blocking agent, please complete the following:
Why do you need to use a neuromuscular blocking agent?
NA
What physiologic parameters are monitored while under a neuromuscular block to assess adequacy of anesthesia?
NA
111
Under what circumstances will incremental doses of anesthetics-analgesics be administered while under a neuromuscular
block?
NA
i) Post-surgical monitoring: please complete the following:
Please identify the physiologic parameters monitored, and interval(s) and for what duration of monitoring.
NA
When will analgesics be administered and at what interval(s)?
NA
If post-operative analgesics cannot be given, please provide scientific justification.
NA
13. Adverse effects:
Describe all significant adverse effects that may be encountered during the study (such as pain, discomfort; reduced growth,
fever, anemia, neurological deficits; behavioral abnormalities or other clinical symptoms of acute or chronic distress or nutritional
deficiency). If genetically-altered animals are used, please describe any potential adverse effects that could be associated with
the desired genotype, if known.
There should be no adverse effects to the snakes in this study. Growth rates are expected to be different across the three
categories but all categories are kept within the normal range. In captivity and in the wild snakes will eat whatever meal size
they can get their hands on. This study is capitalizing on that fact and controlling it to determine behaviors and growth.
Describe criteria for monitoring the well-being of animals on study and criteria for terminating/modifying the procedure(s) if
adverse effects are observed.
All snakes will be checked (visually) five days a week for clean bedding and water. Snakes will be fed one meal per week. All
snakes will be checked at every observation for any signs of poor health. Water bowls will be checked five days a week for
any ecto-parasites that have drown. A veterinarian will be consulted for appropriate procedures in the case of an ill specimen.
It is not expected to have any health problems throughout this study due to the treatment.
How will the signs listed above be ameliorated or alleviated? Please provide scientific justification if these signs cannot be
alleviated or ameliorated.
If health problems cannot be alleviated then the animal will be euthanized
using a Tricaine Methanesulfate. (Conroy et al., 2009)
Note: If any significant adverse effects not described above occur during the course of the study, a complete
description of these unanticipated findings and the steps taken to alleviate them must be submitted to the IACUC as
an amendment to this protocol.
112
14. Methods of euthanasia: Even if your study does not involve euthanizing the animals, please provide a method that you
would use in the event of unanticipated injury or illness. If anesthetic overdose is the method, please provide the agent, dose,
and route.
Species
Pantherophis guttata
guttata
Method
Injection agents
Drug
Tricaine
Methanesulfacte(MS222)
Dose (mg/kg)
250 to 500 mg/kg of
0.7 to 1% sodium
bicarbonate buffered
MS-222
Route
Intracoelomic
injections
Followed by 0.1 to
1.0ml unbuffered 50%
MS-222 solution
(equal parts water and
MS-222)
15. Disposition of animals: What will you do with any animals not euthanized at the conclusion of the project?
All animals will be taken back to my personal collection. None will be euthanized.
113
16. Project Roster: Please provide the names of all the individuals who will work with animals on this project. Please provide
either the University ID number OR a valid UCM e-mail address in order for the IACUC to confirm that the requirements of
training and occupational health for regulatory agencies have been met. Include all investigators, student employees, postdoctoral fellows, staff research associates, post-graduate researchers, and laboratory assistants who will actually work with the
animals. You do not need to include the staff of the vivarium in which your animals will be housed, or staff members that are only
working with tissues or animals post-euthanasia. This roster is specifically for individuals working with live vertebrate
animals.
Training: Supervisors are responsible for insuring that their employees are adequately trained, both in the specifics of their job
and in the requirements of the Federal Animal Welfare Act.
The PI is responsible for keeping this roster current. If staff is added or removed from this project, please amend the protocol to
reflect this change.
Last Name
Cairns
First Name
Middle Initial
Stefan
UCM ID Number OR E-mail address: 700221755
Title/Degree
Primary Investigator
[email protected]
Describe training and experience relevant to the procedures described in this protocol:
Dr. Cairns maintains broad research interests that include applied aquatic
biology problem solving, environmental stream ecotoxicology, environmental
education, application of remote sensing to environmental assessment,
eutrophication monitoring of lakes and reservoirs, restoration and recovery
of damaged ecosystems, limnology, and aquatic ecosystem population dynamics.
He has also had a broad interest in amphibians and reptiles.
Last Name
First Name
Penning
David
UCM ID Number OR e-mail address: 700221755
Middle Initial
A
Title/Degree
Secondary Investigator
[email protected]
I have worked at pet stores for five years. I have helped in the production of thousands of snakes and have cared for more. I
do these kinds of things every day with my personal snake collection of 60+ snakes. I live and breathe this stuff on a daily
basis.
Last Name
First Name
Middle Initial
Title/Degree
UCM ID Number OR e-mail address:
Last Name
First Name
Middle Initial
114
Title/Degree
UCM ID Number OR E-mail address:
Last Name
First Name
Middle Initial
Title/Degree
UCM ID Number OR e-mail address:
Assurance for the Humane Care and Use of Vertebrate Animals
Principal Investigator’s Statement:
This project will be conducted in accordance with the ILAR Guide for the Care and Use of Laboratory Animals,
and the UCM Animal Welfare Assurance on file with the US Public Health Service. These documents are
available from the IACUC Chair. I will abide by all Federal, state and local laws and regulations dealing with the
use of animals in research.
I will advise the Institutional Animal Care and Use Committee in writing of any significant changes in the
procedures or personnel involved in this project.
_______________________________
Principal Investigator
_______________________
Rank/Title
115
_________
Date
Committee Use Only Below
** Conditions necessary for Committee Approval:
Final Disposition of this protocol:
__________ Approved
__________ Not Approved
__________ Withdrawn by Investigator
Date of Action: ______/______/______
I verify that the Institutional Animal Care and Use Committee of the University of Central Missouri acted on this protocol as shown
above.
IACUC Chair
Date
IACUC Attending Veterinarian
Date
IACUC Community Representative
Date
IACUC Member
Date
IACUC Member
Date
IACUC Member
Date
IACUC Member
Date
IACUC Member
Date
116
ROOM /LAB SAFETY INFORMATION
PROTOCOL #________
EXPIRES: ________
Complete this form if you will be using infectious agents, radioisotopes, chemical
carcinogens, recombinant DNA or hazardous chemicals.
RUA#:
BUA#:
CCA#:
Identity of Hazard:
Investigator Last Name:
First Name:
E-mail:
Provide a short description of the agent:
Department:
Phone:
Fax:
This agent / material is hazardous for:
[ ]
Humans only
[ ] Animals only
For which Animal Species?
The agent can be spread by:
[ ]
[ ]
[ ]
Blood
Saliva/nasal droplets
Other:
[ ]
[ ]
[ ]
Humans and Animals
Feces/urine
Does not leave animal
Describe any human health risk associated with this agent:
The precautions checked below apply to this experiment:
[ ] The researcher or his/her technicians are responsible for the feeding and care of these animals.
[ ] The following items must be assumed to be contaminated with hazardous material and must be handled only by the researcher or
his/her technicians.
[ ] Cage
[ ] Stall
[ ] Water Bottle
[ ] Animal Carcasses
[ ] Bedding
[ ] Other:
[ ]
[ ]
[ ]
[ ]
Cages must be autoclaved before cleaning.
Label cages and remove label after decontamination.
Animal carcasses must be labeled and disposed of as follows:
[ ] Incineration
[ ] Biohazardous Waste Container
[ ] Bag and Autoclave
[ ] EH&S will pick-up.
All contaminated waste (soiled bedding or other animal waste) must be properly labeled and disposed of as follows
[ ] Incineration
[ ] Biohazardous Waste Container
[ ] Bag and Autoclave
[ ] EH&S will pick-up.
Personal Protective Equipment Required:
[ ] The following personal protective equipment must be worn/used in the room:
[ ] Lab Coat/Coveralls
[ ] Shoe Covers/Booties
[ ] Disposable Gloves
[ ] Head Cover
[ ] NIOSH Certified Dust Mask
[ ] Disinfectant footbath
[ ] Eye Protection/Face Shield
[ ]
[ ] Fitted Respirator
Type:
[ ] Other:
Describe:
[ ] Personal protective equipment must be removed before leaving the room.
[ ] Personal protective equipment must be discarded or decontaminated at the end of the project
[ ] Hands and arms must be thoroughly washed upon leaving the room
[ ] Full shower, including washing of hair, must be taken upon leaving the room.
[ ] Decontaminate Room (Inform ARS area supervisor when cage and/or room can be returned to general use).
Provide any other information needed to safely work in this room:
117
118
APPENDIX C
Addendum to IACUC# 10-3212
In section 12B, the mass-ration feeding categories are shifting from three categories to two
categories.
The two categories will now be:
Group 1: MR of 20-40%, sample size of nine
Group 2: MR of 41-60%, sample size of nine
Stefan Cairns
David Penning
118

GROWTH RATES AND PREY-HANDLING BEHAVIOR OF

Transcription

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