interindividual associations in dogs - University of California, Santa

INTERINDIVIDUAL
ASSOCIATIONS
IN DOGS
by
BURNEY
J. LE BOEUF 1)
(Department of Psychology, University of California, Berkeley, Calif., U. S. A.)
(With 7
Figures)
(Rec. 3I-1-i967)
CONTENTS
I. Introduction .269
II. Subjects, Materials and Methods.270
III. Results
..275
A. Heterosexual Interactions.275
i. Normative data from the anestrous, estrous, and post-estrous periods
2.
3.
4.
5.
6.
7.
..
of females
.275
The response of individual females to individual males
.
.
.
Behavior in the circle when females were in estrus .
A comparisonof present and previous mating preferences
Behavior in the circle when females were in nonestrus
..
.282
Temporal changes during estrus
.
.
.
.285
Individual differences among males
8. Differences
in the testing condition, tethered vs roving
B. Intrasexual Interactions
i. Female-femalebehavior
2. Male-male behavior
C. Normative Comparisons
..
IV. Discussion
..
Summary
..
References
.
.
277
277
28I
282
286
..286
..286
..288
..290
.29I
.292
.293
Resume ...294
i) Present address: Crown College, University of California, Santa Cruz, California,
U.S.A. This research was conducted at the Field Station for Research on Animal
Behavior in Berkeley, California and was supported by United States Public Health
Service Grant MH-o4noo to Dr FRANKA. BEACH.The work reportedis a condensation
of a Ph.D. thesis submittedto the University of California at Berkeley. I wish to thank
Drs P. R. MARLERand G. E. FRENCH for reading and commenting on the original manu-
script and particularly,Dr FRANKA. BEACH,who overseeredthe work from its inception
to the writing of the final draft.
INTERINDIVIDUAL
ASSOCIATIONS IN DOGS
269
I. INTRODUCTION
Numerousallusionsto individualpreferences,friendships,personalbonds,
sympathiesand antipathies,etc. can be foundin the literatureon the domestic
dog. These citationsemanatefrom a broadsourcewhichincludesdog owners,
breeders, veterinarians
HARROP,
(WHITNEY,
I947; HANCOCK & ROWLANDS, I949;
I96o), and well-knowninvestigatorsof behavior(ENDERS, I945;
TINBERGEN, I951; LORENZ, I952; KINSEY
et al,
I923;
BEACH, I96I).
The
most frequentreportdeals with strong attractionsbetweenparticularmembers of the oppositesex when the femaleis in estrus. Some authoritiesclaim
the male shows preferencesfor certain females while others report that it
is the femalethat selects and refuses to mate with certainmales. Whichever
the case may be, one thing is certain: all of these referencesare based on
subjective impressionsor observations,which are unsubstantiatedby experimentaldata.
Two studiespresentquantitativedata.FULLER & DuBuIs (I962) reported
sexual behaviorscores for a single fox terrier female observed separately
with two males of the same breed during portions of her first estrus.
Attemptsto mate the bitch with a litter mate were unsuccessful,but when
a strangemale experiencedas a stud was introducedcopulationwas effected
within two minutes.
In a more extensive study using 5 male and 5 female beagles,BEACH&
LE BOEUF (in press) observed differences in each female's readiness to
matewith different masculinepartnersover two estrousperiods.Each female
matedreadilywith somemalesbut repeatedlyrejectedthe copulatoryattempts
of others. Females attemptingto prevent mounting barked, growled, and
snappedat males or attackedand bit them.The same males were not always
rejected by all females; a male preferred by one female was frequently
rejectedby another.A female'spreferenceswere consistentfrom her first
estrous period througha subsequentone six monthsto a year later.
The foregoing study was not designed specifically to investigate the
phenomenaof selectivematingand it is probablethat certainfeaturesin the
testing procedureobscuredthe full magnitudeof female preferences. In
some tests the mannerin which the animalswere releasedmade it possible
for a genital lock to occur duringthe first few secondsafter the start of a
test. This had two results. The femalewas tied before she had time to look
the male over, so to speak, and once the animalswere locked, no further
scoringof preferentialbehaviorwas possible.When copulationdid not occur
during the first few seconds of a test, the female exerted obvious control
over the matingsituation,copulatingreadilywith somemaleswhile repeatedly
BURNEY J. LE BOEUF
270
rejecting others, usually for the entire I5-minute observation period. Furthermore, each female was permitted to lock just once a day each day of her
estrous period. After a lock, no further tests were conducted on that day
with other males. Consequently when the female locked with the first male
tested one could not say what might have resulted if a different male had
been used. As a result of this procedure, all males were not tested on the
same days with the estrous bitch and some males copulated more frequently
than others. Lastly, rejection behavior by the female was the only measure
of individual preferences employed.
The primary purpose of the present experiments was to extend the study
of BEACH& LE BOEUFand, specifically, to investigate interindividual asisociations during, before, and after mating in a test situation which maximized
the frequency of opportunities for interaction. The procedure was designed
to facilitate the expression and description of individual preferences by:
(a) permitting all males to have equal time with estrous females and vice
versa, (b) alleviating the difficulties presented by occurrence of the genital
lock, (c) permitting one animal in a test pair to control the frequency and
nature of interaction and, in effect, choose among several partners, and
(d) measuring preferences, in several different ways. In addition, the nature
and frequency of associations of males with males and of females with
females was investigated.
SUBJECTS, MATERIALS AND METHODS
S u b j e c t s'.
The subjects (Ss) were 9 pure bred, 3-year-old Beagles of which 5 were
males and 4 were females. These same animals were used in the study by
BEACH& LE BOEUF (in press). They lived together in a 3/4 acre enclosed
field (see Figure i) from the time they were weaned to the beginning of
the study, with only occasional separation of the sexes when females were
in estrus. During this experiment when the females were not being tested,
they were caged and the males ran free in the field. The Ss were fed after
the completion of a day's tests.
S etti ng.
Tests were conducted in a fenced enclosure measuring approximately
I,700 sq. ft which formed part of the unit where the Ss lived. Observations
were made from a small cabin on the premises which was designed specifically for the purpose. The cabin contained recording instruments and
afforded the observer an excellent view of the testing area (see Figures
i and 2).
~~~~~~~~~~~
-
Figure
2.
~~~~~~~~~~~~~~~~~
The testing area. A tethered animal is restricted to the area surrounded b
small circle (the large circle is not relevant to the present study).
.. ... .......
_....::::::
.:
.....................................................................:...:::.
Figure 3. A female wearing a chastity belt.
INTERINDIVIDUAL
ASSOCIATIONS IN DOGS
27I
CABIN
STAKE
AND
ENCLOSED
CIRCLE
AREA
TESTING
N
/
Figure
i.
CAGES
_
A schematic of the living unit and the enclosure where tests were conducted.
The field area measures approximately 34 acre.
P r o c e d u r e.
The behavior of the following pair combinations was observed in the
same test situation: (a) heterosexual pairs before, during, and after the
female was in estrus, (b) female pairs before, during, and after one of
them was in estrus, and (c) male-male pairs. The test situation provided a
setup in which one animal could completely avoid contact with the other or
terminate contact at any time. One S was tethered to a stake by a 5 ft chain
attached to a fitted harness, and thus resitricted to a circular area with a
diameter of approximately I2 ft (see Figure 2). The perimeter of thiscircular area was outlined with gypsum to facilitate observations and scoring
behavior. The other S, the roving animal, was released into the testing enclosure from the observer's cabin situated 20 ft from the tethering stake.
The roving animal was allowed 5 minutes in the field, the duration of each
test. It is reported that the type of interactions observed between an estrous
female and a male dog do not change substantially if the test duration is
extended beyond 5 minutes to 30 minutes (BEACH & LE BOEUF, in press).
Daily tests with each pair of Ss included two observations, one while the
animal was tethered and one while it was roving free.
Behavioral
items
recorded.
The following gross measures were recorded: (a) whether or not the
roving animal went to the tethered animal and made physical contact, (b) the
time spent by the roving animal in the circle with the tethered animal, and
272
BURNEY J. LE BOEUF
(c) the numberof entrancesand departuresinto and out of the circleby the
rovinganimal.Behavioralinteractionsbetweenthe rovingand the tetheredS
in the circle were described with categories similar to those used by BEACH
& LE BOEUF(in press). In this schema, shown in Table i, an attempt was
made to reduce behavioralinteractionsto discrete stimulus-responseunits
or episodes. The term "episode" was used to refer to the initiating act of
one animal plus the response of the other.
TABLE I
Categories of social and sexual behavior in dogs
Stimulus Units of Behavior*
Code
Description of Behavior
I
Approach: moves to within 2 feet
2
Partial investigation: brings nose within i foot of anogenital region or makes
momentary contact with that area
3
Investigation: sniffs and/or licks anogenital area for at least 5 seconds
4A
Pre-mount contact: partial mount, forepaws on back, chin over back
4B
Prance: forepaws extended, body thrown back on haunches, head cocked to
one side; barking and vigorous tail wagging may be involved
Present: hindquartersdirected to the other animal and tail is deviated laterally
4C
5
Mount:forelimbclaspwithoutpelvicthrusts
6
7
Clasp and thrust: Same as 5 with several pelvic thrusts
Behazior of intromission: same as 6 but thrusts are more rapid and include
pelvic oscillation, "steppingand treading" of the hindlegs
Response Units of Behavior**
Code
Description of Behavior
Ai
Stand: Maintains erect posture for at least 5 seconds when mounted or in-
vestigated
A2
B
C
Stand with Tail Deviation: same as Ai plus lateraldeviationof tail
Face: whirls aroundto face other animalwhen investigatedor mounted
Sit: the nonerect female does not rise when mounted or investigated
D
Avoid: Movesor pullsaway,sits or lies downto avoidmountor investigation
E
Threat: barks, growls, snaps, lunges or any combinationwhich prevents the
initiation or continuationof behavior by the other animal
Attack: chase, drive, bite or any combination
F
The
estrous
period.
A female's estrous period was defined and determined by a combination
of behavioral signs, genital swelling and/or bleeding, and vaginal smears
* Malesdisplayall behaviorsexcept4C. Femalesdisplayall behaviorsdescribed.Any
activitynot directedto the rear of the other animalbut ratherto the head or side is
suffixed by an "H"or an "S".
** All responseunits are shownby the female.The male respondsto a femaleby
standing(AI) or by movingaway (D). FemalesterminateAi and A2 responseswith
B, D, E, or F, or they standuntil dismounted.
INTERINDIVIDUAL
ASSOCIATIONS IN DOGS
273
taken before each day's tests. A femalewas classifiedas being in behavioral
estrus on those days in which the following conditions were satisfied:
(a) swelling with or without vaginal discharge,(b) a vaginal smear of the
late proestrousor estrous type, i.e., primarilycornified epithelium,with or
without red blood cells, and with but few nucleatedepithelialcells, (c) the
female "stood",deviatedher tail laterallyand permitteda male to mount,
clasp her hindquartersand execute severalpelvic thrusts.With the first two
conditionssatisfied,one mountwith clasp and thrustsby one male, in which
the female stood and deviatedher tail, was sufficient to classify the female
as being in estrus on that day. The behavioralcriterion of standing and
"curlingthe tail", alone, has frequentlybeen employedas an indicationof
estrus in the bitch
(WHITNEY,
I947; HANCOCK & ROWLANDS, I949; GRA-
HAM, I96I; ASDELL, I966).
One female, Blanche,was tested while in naturalestrus. The other three
femaleswere broughtinto estrus by means of 2 intramuscularinjectionsof
estrogen1) (.38 mglkg of estradiol benzoate, Schering "Progynon",3.3
mg/ccin sesameoil), spaced48 hours apart.The hormonewas administered
during the anestrousperiod, 4-6 months after a female's previous natural
estrus. It was known from previouswork that the bitch usually comes into
estrus I-5 days after the second injection and remains,in estrus for
approximatelyIOdays.
Special
equipment.
In heterosexualtests it was importantto maintainthe female stimulus
to each male in as constanta conditionas possible.To do this, and in order
to run several combinationsof tests per day, the occurrenceof complete
copulationwith insertionand genital lock was prevented.This was effected
by fitting eachwith a "chastity"belt whichcoveredthe entireanogenitalarea
and preventedmales from achievinginsertion (see Figure 3). The belt was
made of thin vinyl plastic, and small holes in the transparentmaterial
permittedthe femaleto urinateand allowedfor the transmissionof olfactory
and gustatorycues to the male. After a brief period of adaptation,females
becameaccustomedto wearingthe belt. It did not impedethe movementsof
the femalenor did it produceany apparentdecreasein her interestin the male
nor the male'sinterestin the female.
It was also necessaryto adaptbothmalesand femalesto the harnessesand
the tether. This was accomplishedduring the same 6-day pre-experimental
i) The hormoneswere suppliedby Dr PRESTONL. PERLMAN
of the Biological Research
Department, Schering Corporation,Bloomfield, New Jersey.
274
BURNEY
J. LE BOEUF
period during which females were adapted to the belts. Harnesses were worn
at all times; chastity belts were installed for tests only.
Observation
periods
and their
duration.
Tests involving estrous females were started 8 days before the female
received her first estrogen injection and continued without interruption
(except for a few days when the weather conditions made observation
impossible) until the ioth day after the female was last mounted. The 8 observation days prior to injections were called the anestrous period; days with
mounts in which the female stood and deviated the tail constituted the estrous
period; and the io days following the last day of estrus was called the postestrous period. Anestrus and post-estrus combined were called nonestrus.
Combinations
or groups
of Ss tested.
Since tests with each S included observations when the animal was tethered
and when he or she was roving free, and since each female was tested during
estrus and nonestrus, several combinations'of sex and female "reproductive"
conditions resulted. These combinations and their abbreviations (called
groups) are shown in Table 2 and will be referred to in a later section.
TABLE
2
Combinations of subjects tested
Groups
Roving Animal
Tethered Animal
M-EF
EF-M
M-NEF
NEF-M
NEF-EF
EF-NEF
NEF-NEF
M-M
male
estrous female
male
nonestrous female
nonestrous female
estrous female
nonestrous female
male
estrous female
male
nonestrousfemale
male
estrous female
nonestrous female
nonestrous female
male
Time
and order
of testing.
Two females were brought into estrus at the start of the experiment while
the other two females served as anestrous Ss. When testing was completed
on the first two females, they served as anestrous Ss and a third female,
used formerly as an anestrous S, was brought into estrus. The last S came
into natural estrus during the post-estrous' tests of the first two females
tested.
Heterosexual pairs and female-female pairs were observed on the same
days with the former always tested first in the day. All tests involving
INTERINDIVIDUAL
ASSOCIATIONS IN DOGS
275
femaleswere completedbefore observationof male-malepairs were initiated.
Each male was tested IO times with each other male over a period of
30 days.
To control for possibleorder effects in the daily tests, individualsof one
sex were run first to individualsof the other sex on alternatedays. For
example,an estrous female was run to males before they were run to her
on one day and the procedurewas reversedon the following day. When
two females were being tested on the same day, they were alternatelyrun
first and second. Within each group, the order of release or tetheringwas
varied in a way which preventedsystematicerror.
RESULTS
HETEROSEXUAL INTERACTIONS
Normative
post-estrous
data f rom the anestrous,
periods
of females.
estrous,
and
Table 3 shows the percentageof days that the roving dog visited the
tethered dog and initiated a behavioralepisode. Males visited females on
93.lYo of the days that the latterwere in estrus, an increaseover the number
of days females were visited when they were in anestrus (78.6%) and
post-estrus(72.0%). Similarly,femalesvisited males more frequentlywhen
they were in estrus (76.2%) than in anestrus (27.8%) or post-estrus
(4255%). Under each female condition,males visited females more often
than females visited males.
The percentageof total test time spent by the roving dog in the circle
with the tethereddog is shown in Table 4. The findings representedin this
table supportthe conclusionssuggestedby Table 3. Accordingto these two
measures, the sexes are generally most attractedto each other when the
female is in estrus.
Detailed examinationof Table 3 and 4 shows that one female was far
more responsiveto males than were the other three females.Kate'svisits to
males totaled 89%, ioo% and ioo% of the tests during her anestrous,
estrous, and post-estrous periods, respectively. The response of the other three
females was much lower during their respectiveperiods. Kate also spent
more time with males,once she visited them,than did the other females.The
magnitude of these individual dif ferences precludes further normative
analyses. A more meaningful approach, for our purposes, is to examine the
response of individuals, the source of the variation.
BehaviourXXIX
I8
TABLE 3
Percentage of days that the roving dog visited the
FEMALES
~~~~Tethered
Days
MALES
CLARK
75
JOHN
12
EDDIE,
62
88
KEN
BROADTUS
MEANS
i8
E
8
A
100
8
io
PA
100
78
Roving
i8
1o
E_P
0
100
12
22
20
12
83
100
40
12
100
I10
90
i00
90
25
II
0
100
25
i00
8o
700]
17.2
100
167.495.6
BLANCHE
SPOT
PEGGY
Tethered
8
12
I0
E
P
A
8
A
100
100
38
50
83
12
I0
E
PA
I17
0
30
30
0
20
0
100
100
100
67
50
83
0
0
100
50
7
Te
g
A
Roving
8
A
12
I0
E
P
42
0
100
30
89
33
89
40
0
92
20
70
12
5
0
100
40
0
50
0
90
100
100
0
83
0
i00
i00
90
0
100
50
100
100
100
12
100
40
100
182.0
90.0
84.0
4.8
70.0
140]
i00
88
88
Roving
Tethered
12
8
I0
P
E
63.2 36.0] 82.8 86.6
44.0]
0 7I.8 20.0
82.2
TABLE 4
Percentage of total test time spent by the roving dog in
tethered dog
FEMALES
MALES
PEGGY
Tethered
Roving
E
A
P1 A E
CLARK
2-7
JOHN
I125
KEN
5
33
BROADUS
21
EDDIE,
MENS
A= Anestrus
30
72
12
4
I
0
3
82
II
E = Estrus
0
A
12
I
I
I
84
0
14
E__Pi
6
4
15
<1I
.2 35.8
'74I8o
P.
74
<I
381I3
Tethered
6
14
Roving
A
E
P.
BLANCHE
Tethered
Rovi'ng
P
E
A
E__PI_A
0
-O
1
I7
SPOT
7
i6
31i
521i8308
P= Pos testrus
i
0
<1I
37
34
62
I
2
0
15
0
3.8
0
2
32
I
28
I
57
0
3
01I3
26.
o
41
6 25
2879
31I
1725682.
8-8
14
38
34
I
0
20
4
451I
0
38
I
<1
01I5
44
<I
0
20.0
0
T
A
39
I
2
0
0
2
15
24
27
.62I4
INTERINDIVIDUAL
ASSOCIATIONS
IN
DOGS
277
The response
females
of individual
to individual
males.
The group analysis showed that females in estrus were attracted to males.
Although this statement is true it could be misleading if taken to imply that
all females were universally attracted to all males. Tables 3 and 4 show that
three of the four females visited some males more frequently than others
and also spent more time with them. For example, Peggy visited Broadus
and Eddie every day that she was in estrus and spent 84% and 74%
of her test time with them in the circle. In contrast, she visited Clark and
Ken only 22% and II%o of the time and spent only 6% and i.% of her
time with them. Spot and Blanche showed similar variation in their response
to males. It should also be noted that no female responded differentially
to males during anestrus. However, response tendencies evident during
estrus tended to persist into the post-estrus period.
These data suggest that all females were 'ot equally attracted to all males.
In fact, some females spent no more time with certain males when they
were in estrus than when they were in anestrus. This can be seen in the
combinations: Peggy with Clark and Ken; Spot with Clark; and Blanche
with Clark and Eddie as shown in Table 4. Hlowever, these differences in
the response magnitude of individual estrous females derive from two gross,
correlated measures, only. Additional insight is provided by the behavior
of the pairs of dogs when they were together in the circle.
Behavior
in the
circle
when
females
were
in estrus.
Before presenting these results, some of the measures recorded must be
described. When released into the field, a male usually approached the
female, investigated her anogenital region, and if she was in estrus, mounted
from the rear, clasping the female's hindquartersi and executing several
pelvic thrusts. After approximately 5-30 seconds of thrusting without introa
mission, the male dismounted or was thrown off by the female. This pattern
was often repeated as much as 20 times in 5 minutes, and was not unlike
behavior observed normally when the male has difficulty obtaining insertion.
Since insertion was prevented in this study, a mount with clasp and thrusts
(MCT) was the most nearly complete form of sexual activity possible.. A
female was maximally cooperative if she stood and deviated her tail laterally
when mounted. Ordinarily, this response would have facilitated insertion
and the establishment of a genital lock.
The positive behavior of an estrous female to a male sometimes took an
active form which some have called "'courtship"(FULLER & DuBuis, I962)
or "'solicitation"behavior (WHITNEY,
1947). The latter term is used generally
278
BURNEY
J. LE
BOEUF
to refer to all female-initiated activities described in Table i and indicated
by the symbols: 4A, 4B, 4C, 5, 6, and 7. Activities directed to the head, side,
and anogenital region of the male were all considered equally.
The estrous female was not always cooperative. Besides avoiding the
male, the female might activily prevent sexual activity by (a) barking,
growling or snapping and lunging at him or by (b) biting andlor driving
him away. These two responses, symbolized as E and F in Table i, will be
TABLE 5
Peggy's response to 5 males during an i8-day estrous period
Day of No. MCT Total
ist MCT
MCTs
Days
Roving
Males
--
No. Female
Negative Episodes
Solicitations Proportion
Percent
Tethered
Clark
9
-
John
Eddie
3
-
9
0
-
9
3
3
24
II
I4
I5
I
1/29
34
8
7
34
20
3/94
3.2
I4
1
9-+
I.->9
9
Broadus
X
-*8
o
8
0
I3
2
13
I27
70
3
15
99
142
I
-
0
5
0
0
0
9
-
6
5
I4
--->
Ken
8
27.4
0
0/54
2.8
0
8/285
0/230
75.6
0
149/197
0/7
I
I7
2/34I
.5
2
i6
94
177
0/176
0
41
40
353
131
322
194II034
I /496
i8.8
.2
9
o
321117
30
I63
221
TABLE 6
Spot's response to 5 moles during a 12-day estrous period
Roving
Males
of
Day
Ist
--
MCT
No.
MCT
Days
Total
No.
MCTs
Solicitations
Female
Negative
Episodes
Proportion
Percent
I8/I9
94.7
Tethered
Clark
_
8-9
-
o 80
John
R
Eddie
>9
8
-
Ken
$-*9
Broadus
z
X
t
9
7/I I
63.6
O
8
4
7
4
2/62
9
8
7
8
3
2
I0
0
15
0
37177
7/83
7
2
0
2
i5o/i66
I 6/38
90.4
0
0
0
2
I0
56
o
II/I58
7.0
I
9
49
4
9
e
&lt;
0
7
o8
-o
0
3
-
-
e
0
0
9
8
9
9
o
0
t
9
I8
75
0
t
15
71
8
10/41
3/1I39
226/46I
35/333
24.4
3.2
48. I
8.4
42. I
2.2
49.0
10.5
IN
ASSOCIATIONS
INTERINDIVIDUAL
279
DOGS
TABLE 7
Blanche'sresponse to 5 males during a I2-day estrous period
Roving
Males
Clark
Tethered
! -e 9
Q
John
Eddie
Day of No. MCT Total No. Female NegativeEpisodes
Days MCTs SolicitationsProportion Percent
Ist MCT
->
3
8
e
8 9 &lt;
8
5
4
8
9
5
>
9
Q
e
8
8
->
I
4
I
2
-
Q
Ken
Broadus
Q
X
8 8
z
9
8
o
2
0
0
7
9
63
46
I
5
0o
Io
67
5
9
8
-~ Q29
-
22
t
2
0
0
0
II
33
0
0
9
I4
i6
28/62
45.2
i/8
I2.5
13/I48
i/io6
8.8
54/73
74.0
1.0
i/8
12.5
1331303
43.9
I/49
2.0
I8/233
8.I
2I
4/96
4.2
235
36
68
246/8i9
8/267
30.0
ioo
I4
98
40
3.0
TABLE 8
Kate's response to 5 males during an 8-day estrous period
Roving
Males
->
Day of No. MCT Total No. Female NegativeEpisodes
MCT Days MCTs SolicitationsProportion Percent
Ist
Tethered
-
Clark
9
_1
8 -9
9
John
Q
Eddie
Ken
Broadus
X 8
8
&lt;
2
7
I
7
74
64
5
2
6
4
4
I2
,3*9
7
I
I
9 &lt;
8 &lt; Q
9 o
9
8 -
4
2
2
23
5
33
2
6
22
4
4
2
4
I5
II
I7
I29
23
I32
Q &lt;
8>9
9 &lt; 8
0
io/i6i
6.2
4
0
i6
2/I4I
I14
0/27
0
3.3
I
3
0
7
0
2/61
i1/26
0/80
32/i65
6/1iI2
6/85
3.8
0
194
54
2
i1/64
7.I
i.6
I
32
491464
io.6
1I /458
24
called "threat" and "'attack", respectively. Negative episodes are those in
which the female responded with threat or attack.
Tables 5, 6, 7, and 8 show the response of each female to each male for 3
categories of behavior: the time and frequency of MCTs, the frequency of
solicitation behavior, and the percentage of negative episodes. The data in
these tables show that Peggy, Spot, and Blanche, each reacted positively to
some males and negatively to others, i.e., they showed preferences. This is
280
BURNEY
J. LE BOEUF
best indicated by considering one fenmalein detail. For example, Peggy
clearly preferred Broadus and Eddie to Clark and Ken. She vis,ited Broadus
and Eddie every day that she was in estrus and spent the majority of her
test time with them when they were tethered (Table 3). On the contrary,
she rarely visited Clark and Ken and when she did she remained with them
for only a short time (Table 4). Table 5 shows that on these few visits,
Ken never mounted. Clark mounted Peggy for 3 days but not until the
14th day of her i8-day estrous period. On the other hand, Peggy's visits to
Broadus and Eddie resulted in numerous mounts as early as Day 2 and 3,
and for a period of i6 and 15 days, respectively.
When Peggy was tethered and the males ran free, Ken and Clark did not
mount until the 14th day of her estrous period. Once again, Peggy's
response to these two males contrasted sharply with her response to Broadus
and Eddie, who mounted sooner, on more days and more times per day.
Peggy solicited Eddie and Broadus frequently, particularly when they were
tethered and she was free. She rarely solicited Clark and never solicited Ken.
The proportion of negative episodes to total episodes initiated by the male
when he was roving indicates that Clark and Ken did not mount frequently
because they were prevented from doing so by the female. Twenty-seven
percent of the episodes initiated by Clark and 76%vof those initiated by
Ken, Peggy actively repulsed with threats and attack. Markedly lower
percentages on the same measure were obtained by the other 3 males: John
Eddie (2.8%), and Broadus (0.5%).
(3.2%),
The response of the other females can be compared to Peggy's (Tables- 6,
7, and 8). Both Spot and Blanche were most positive to Broadus and somewhat less so to John. Spot, like Peggy, was most uncooperative with Clark and
Ken. She did not stand to be mounted and she rejected them 9 out of every
iO times that they initiated an episode. Blanche was positive to Ken, in that
he mounted often and was at times solicited, but she also rejected him
frequently. The most interesting point is that Blanche displayed the greatest
aversion to Eddie, one of Peggy's favorites. This suggests that the antipathy
elicited by a male does not depend on an attribute peculiar to him to which
all females respond, e.g., his outward appearance. Eddie obviously affected
Peggy and Blanche dif ferently.
Kate did not show the antipathies shown by other females. She visited each
male every day that she was in estrus and spent from 47% to 68% of her
time with them. With Kate, no one male ranks far above or far below any
other on any of the measures shown in Table 8.
Preferences were suggested in still another type of behavior shown by the
female which some investigators have called "teasing" (WHITNEY,
1947).
INTERINDIVIDUAL
28I
IN DOGS
ASSOCIATIONS
A female in estrus often terminates an investigation or mount by running
away from the male. The male usually gives chase and after a short run, the
female comes to an abrupt halt and may stand once again. If the male does
not follow her, the female often returns to the male and solicits his attention
(FULLER & DuBuis, I962; LE BOEUF, I967). Females frequently ran
to, away from, and back to tethered males in this study and these data are
shown in Table 9. The measure is the mean number of circle entrances by
the female on days in which she visited tethered males.
TABLE 9
Mean number of circle entrances on days in which female visited the male
Roving Females
Tethered
Males
Clark
John
Eddie
Ken
Broadus
Means
A
=
E =
P =
A
I
Peggy
P
E
A
Spot
E P
Blanche
A E P
A
Kate
E
P
I .5
0
0
I
0
0
I
0
1.3
2.5
I.,
I.8
I
0
3.2
I
0
4.2
I
1.2
2.5
1.3
1.1
I
2.5
T.1
0
3.4
I.5
I
I
0
L.I
2.2
2
I
0
0
I.7
0
0
2.9
0
1.2
2.8
1.2
I
3.0
I
0
4.4
I .4
I
4.2
I
I .4
2.1
1.2
I.2
2.0
0
2.7
o.8
0.4
2.7
0.4
T.2
2.4
1.2
.6
anestrus
estrus
post-estrus
All females ran in and out of the circle most frequently when they were in
the estrous condition. The mean number of circle entrances during this period
for each female, with the exception of Kate, reflects the same preferences
for particular males which were evident in the measures previously discussed.
The conclusion is that females "'teased"preferred males only, or put more
objectively, they returned to preferred males more often after leaving them
than they did to nonpreferred males.
>A comparison
e r en c e s.
of present
and
previous
mating
pref-
The various differential responses of estrous females to certain males
suggest preferences which are remarkably similar to those shown previously
by these same females to the same males during their first and second
natural estrous periods. Table io, adapted from BEACH & LE BOEUF (in
282
BURNEY
J. LE BOEUF
press), shows the percentage of male acts (symbols i through 4A in
Table i) to which femalesrespondedwith threator attack.Scores from both
estrous periods are combinedto form the rejectioncoefficients shown. The
similarityand consistencyof present and previous mating preferencesare
even more surprisingwhen one considersthe numerousdifferences already
pointedout betweenthe two studies, and the fact that a span of two years
separatedthe first estrousperiods from those observedin the presentstudy.
The presentresultsalso suggestthata female's,preferencesare not attenuated
by the artificialinductionof estrus with exogenoushormones.
TABLE io
Rejection coefficients from two estrous periods for each female with each
male (adaptedfrom Beach and LeBoeuf, in press)
Female
Male
... . . .... ..... .... .... ..... ... .. ..... ...... .. .... ..... . ..... ... .. ................
Clark
John
Eddie
Ken
Broadus
Peggy
Spot Blanche Kate
............ .... . . .. . . .......................................................................
33
6i
55
5
10
0
IO
I5
2
I2
8i
0
33
4
58
59
6
30
12
o
in the circle
when females
were in nonBehavior
estrous.
Only a small number of episodes took place during the anestrousand
post-estrousperiods of each female. No mountingoccurredand solicitation
was rareduringtheseperiods.A few negativeepisodeswere observedduring
anestrusbutthey were distributedamongseveralmales.No malewas rejected
during post-estrus.More will be said about the anestrousand post-estrous
periodsin the next section.
during estrus.
Temporal
changes
In additionto displayingindividualbiases to males, females differed in
more general ways amongst themselves. Each female responded to the
administrationlof exogenoushormoneswith different latenciesto the onset
of estrus and its duration(see Figures 4-7). Kate not only failed to show
preferences,but was more "social"than other females when she was not
in estrus (see Tables 3, 4 and 9). Peggy solicitedfrequentlywhen she was
in estrus while Spot solicitedonly rarely.Spot respondednegativelyto most
I
80
70
-
z
-
50
-
I
I
i
I
I
MOUNTS BY MALES
A-
SOLICITATION BY FEMALE
X-
NEGATIVE EPISODES
~~
~~~~~~~A
I
U
40
8
283
DOGS
PEGGY
0-
60
IN
ASSOCIATIONS
INTERINDIVIDUAL
r
A
30
30
/<
1
II
X
12 13 4
3 456890
2
If
5 16 17 18
ODAYS
Figure 4
80
70
50~~~~~
I
I__
-
I--- J I
SPOT
* - MOUNTS
A-
I
I
I
I
I
I
BY MALES
SOLICITATION BY FEMALE
S - NEGATIVE EPISODES
60-
50
:) 4 0130
\!
20/1
*~\
10
II
I
/
I~1
II
3
6
4I
DAYS
Figure 5
I1
284
BURNEY
J. LE
BOEUF
- l
T-----------I
80
BLANCHE
70
*-MOUNTS
A60
-
540
-
BY MALES
SOLICITATION BY FEMALE
X - NEGATIVE EPISODES
30
--4i
IA---4.A---.--
I
I
8
U
10
I
I
It
10
I
2
3
4
5
6
DAYS
7
11
12
-11
1
Figure 6
--- -I
80 60~~~~~~
70
I
I
I
I
I
KATE
0-
MOUNTS BY MALES
A-
SOLICITATION MY FEMALE
UXNEGATIVE
|
EPISODES
|\
30~~~~~~~~~~~
1
l
l
2
3
4
5
Figure 6
60
6
7
8
0
~~~~~DAYS
-
50~~~~~~~~~~~~~~~~~~~~~~'
D
40~~~~~~~~~~
CY~
~ ~~~~~~~DY
Figures 4-7. Temporal changes in the frequency of MCTs, solicitation behavior and
negative behavior. Estrogen was administeredon the days indicated by the arrows.
INTERINDIVIDUAL
ASSOCIATIONS
IN
DOGS
285
males far more frequentlythan did other females. The time course of the
measurestreatedin Tables 5-8 are depictedin Figures 4-7. They show the
temporalchanges in the frequencywith which females solicited, responded
negativelyor were mounted,from the time estrogen was administered(or
proestrusbegan) to several days after the female ceased to allow mounting.
All females permittedrelatively few mounts at first. Mount frequency
rose, graduallywith some females and more quicklywith others, to a peak
near the three quarter mark of the estrous period with Peggy and Spot
and near the middleof the estrous period for Blancheand Kate.
The temporalorder of negative behaviorwas quite different for each
female.The peak was near the middleof Peggy's estrousperiodand did not
coincidewith those days in which she was most frequentlymounted.Spot
showeda bimodaldistributionfor mounts.However, she was most negative
at the same time that she was most positive for mounts.Blanche,in natural
estrus, was most negative during proestrus but the figure shows another
peak of negative behaviorwhich coincidedwith her high point for total
mounts. Both Blanche and Peggy showed few rejection responses on the
last few days of their estrous periods. Kate displayed a much different
patternof responce.She was mostnegativetowardthe end of her periodwhen
mountfrequencywas low. These datado not supportthe frequentsuggestion
(e.g., GRAHAM, 196T)that the femalerejectsthe male only duringthe period
immediatelyprior to and just after she is most "ready".
With Peggy, solicitation behavior closely paralleledmount frequency.
Towardthe end of her estrous periodshe continuedto solicit when she was
no longer mountedand she no longer rejectedany male. Blanchebehaved
similarly, but she, unlike Peggy, did little soliciting when she was most
frequentlymounted.Kate solicitedmost frequentlyduring the early part of
her estrousperiodand was thus just the oppositefrom Blanche.
Individual
differences
among males.
There are many problemsinvolved in determiningwhether males show
preferencesfor certainfemales.For example,one must be able to show that
all females are equally in estrus at the same time, and that the male's
behavioris not just a reflection of the female's aversion to him. In the
present study, it was not possible to control the circumstancesin such a
way that permitsunequivocalstatementsabout male preferences.However,
markeddifferences in the responseof individualmales to all females were
evident. Table 3 shows that John was an infrequent visitor of females
regardlessof their condition.In fact, he spent no more time with estrous
females than Broadus spent with anestrous females (Table 4). This low
286
BURNEY
J. LE BOEUF
response was not occasioned by the negative behavior of females for John
was rarely threatened or attacked. Broadus was also rarely rejected by
females, yet he mounted each female much sooner than John (Tables 5-8).
Unlike John, Broadus rarely failed to visit a tethered female and he spent
more time with them than did other males (Tables 3 and 4). Broadus was
the most popular male in the sense that he was allowed to mount earlier and
more often; he was more frequently solicited and he was least often rejected.
Clark and Ken were most often rejected. With two females (Spot and
Blanche), both males were rejected approximately an equal percentage of
time. However, Ken's scores were based on many more episodes. This
disparity indicates something which was clear from observing the behavior.
Ken was vigorous and persistent in his attempts to copulate despite being
repeatedly rebuffed. In contrast, one or two snarls or snaps at the start of
each test were sufficient to keep Clark away for the remainder of the
period (see Table 4).
Dif ferences
r o v i n g.
in
the
testing
condition,
tethered
vs
Tables 3 and 4 showed that the outcome of a test depended on whether
the male or the female was tethered. Tables 5-8 provide additional data on
this point. Females were mounted more frequently when they were tethered
and the male was free. This is not surprising since some females did not
go to some males when they had the choice. In four situations where a
female was mounted by a nonpreferred male, it was always when the male
was free and the female tethered (Tables 5-7: Peggy and Ken; Spot and
Ken; Blanche and Clark, Eddie). On the other hand, females solicited more
and rejected less when they were free and the males were tethered. The first
day a female was mounted and the number of days that a male continued to
mount were not affected by which partner was tethered.
INTRASEXUAL INTERACTIONS
Female-f
emale
behavior.
The collection of symmetric data from each female during anestrus, estrus
and post-estrus was made difficult by the fact that the various conditions
could not be held constant. To facilitate the following analysis, anestrous
and post-estrous data were combiner and will be called non-estrous data.
Table ii shows the percentage of visits and test time spent by females in
one condition with females in the same or opposite condition. The estrous
female group visited other females most frequently and spent the greatest
amount of time with them. They were, in turn, least often visited by others.
INTERINDIVIDUAL
ASSOCIATIONS IN DOGS
287
TABLE I I
Percentageof days rovingfemalesvisitedtetheredfemalesand the percentage
of total test timespent in the circlewhen the femaleswere groupedaccording
to "reproductive"
condition
Groups
Per cent
Visits
Per cent
Total Time
EF-NEF
74
NEF-EF
42
6
NEF-NEF
55
8
I5
Interactionsbetween two females were infrequentas comparedto those
observedbetweenheterosexualpairs or in tests involvingtwo males. More
than 3 episodesper visit day betweentwo females was rare. Episodeswere
most often initiatedby the roving female (74 %) ratherthan the restricted
female (26 %o),regardlessof either animal'sreproductivecondition.Most
episodesinvolvedbrief investigationof the heador anogenitalregion.Mounting between females was also observed. In all cases, the roving female
mounted the tethered female. This activity was most common when the
nonestrous female was free and an estrous female was tethered. Estrous
females rarely mountedtetherednonestrousfemales.
Females rarely respondednegativelyto mounts or investigationby other
females except on one occasion. For two days, Peggy and Blanche were
run to each other when the former was in estrus and the latter was in
proestrus.Peggy courtedBlanchevigorously,initiatinga total of 79 episodes
in these two days. Of these, 38 were investigatory,I4 involved mounting
or attemptsto mount, and 27 were terminatednegativelyby Blanche.The
negative behavior displayedby Blanche to Peggy was as intense as that
directedto males. Despite the threats and attacks, Peggy, like a sexually
aggressivemale, persistedin her attemptsto investigateand mount. These
data are not includedin Tables i i and I2 becauseof the small numberof
observations.
Table 12 shows the response of each female roving to other tethered
females.Kate showedthe highest percentageof visits under each condition.
All females visited most frequently in the EF-NEF situation except for
Blanche,who visited most frequentlywhen both she and the tetheredfemale
were in nonestrus (NEF-NEF). The percentage of test time that each
female spent in the circle yields a similar picture.
288
BURNEY
J. LE BOEUF
TABLE I2
Individual differences in female-f emale interactions as measured by the
percentage of days that individual fenales visited tethered females and the
percentage of total test time spent in the circle (in parentheses)
Rovingfemale
Kate
Peggy
Blanche
Spot
EF-NEF
NEF-EF
NEF-NEF
95 (38)
76 (9)
5o (6)
I2 (4)
76 (I5)
52 ( 2)
29
26
( 9)
91
33 ( 7)
71 (
5)
50 (IO)
(2)
( 2)
Unlike their behavior with males, females did not show clear preferences
for the company of other females. However, there is a problem in detecting
associations of this kind between females which is due mainly to the nature
of the interactions engaged in by a pair of females. The estrous female is
not mounted as frequently by another female as by a male and, perhaps
because of this, the female has less occasion to threaten or attack its feminine
partner. We can look at the simple measures of percent visits and time spent
with each other, and indeed these reveal some interesting disparities, but
presented alone, they lack conviction.
Male-male
behavior.
Males visited other males 68 % of the time and spent 3I % of their test
time with the tethered dog. The response of individual males to each other
for these two measures is shown in Table 13.
TABLE
I3
Percentage of days that males visited each other and the percentage of
total test time spent with the tethered dog (in parentheses)
Tethered
Clark
Clark
John
IOO
John
30
30
10
40
(6)
(o)
(I9)
55
-
80
Ken
(75)
IOO
(44)
(I6)
90
IOO
(66.3)
Mean %
(I7)
IOO
Mean %o
Broadus
90
Eddie
ioo
(83)
Ken
(54)
(63)
Broadus
Roving
Eddie
(38)
20
50
50
(Io)
(i9)
(12)
100
100
(26)
95
(24)
(54)
(42)
90
8o
(36)
40
(II)
8o
0
(23)
(o)
85
22.5
(32.7)
(9.5)
(50
8o
(i6)
65
(I64)
-
65
(30)
62.5
(29.6)
INTERINDIVIDUAL
ASSOCIATIONS IN DOGS
289
A comparison of the mean percentages in Table 13 indicates that the
males who visited other males most frequently were themselves least frequently visited. For example, Clark made contact with all males every day
that he was tested, but other males visited him only 40 % of the time. On
the other hand, Eddie did not visit others very often (22.5 %) but was
himself visited in virtually every test (95 %). This relationship is also
apparent for the time measure.
A partial explanation for the discrepancies between cells in Table I3 is
suggested by the behavior males displayed to each other. Interactions between
males frequently involved elements of ritualized aggression which were unlike
the negative behavior shown by estrous females to males. Aggressive encounters between males resembled several descriptions in the literature (DARWIN, I872; BUYTENDIJK, I936; LORENZ, I952, I953). One male, usually the
free animal, approached the other, growling and walking stiffly with his tail
held high, wagging briskly, and arched over his back. The other dog frequently
responded in kind while the two stood nose to nose or walked together side
by side. Encounters such as these were as brief as a few seconds or often
as long as 2-3 minutes, and rarely terminated in a serious fight. Typically,
the behavior subsided gradually with no dog "losing face". Mutual genital
investigation was commonly observed at this time. If a male did not bristle
when approached aggressively, he responded by retreating, cringing, or
rolling over on his back while the other stood growling over him. Aggressive
encounters such as these, where one dog clearly submitted to the other, were
called unilateral. All other interactions involved head or anogenital investigation. Male-male mounting was not observed during any of the tests.
TABLE I4
The proportion of visit days in which aggressive behavior was observed
between males. The figures in parentheses refers to the number of episodes
in which aggression was unilateral, i.e., one animal cringed or moved away
from the other; the arrow points to the "Winner" in the encounter
Tethered
Clark
Clark
John
IOIO
Eddie
O/IO
Ken
E3roadus
John
Roving
Eddie
Ken
8/9
0/3
0/3
o/I
-
2/2 (2)
2/5 (2)
3/5
2/8 (2)
t
6/io (6)
t
8/io (8)
~~~~t
5/I0
3/9 (3)
1/4
o/8
o/o
Broadus
(2)
IO/IO(3)
I/9
o/8
290
BURNEY J. LE BOEUF
The data in Table I4, showing the number of days that aggressive behavior was observed and the direction it took relative to the number of
visit days for each combination of males, suggest that a dog's readiness to
visit a tethered dog was related to the aggressive relationship between the
two. Table I4 shows that Clark and John were often engaged in aggressive
encounters with others from which they did not retreat. They were always
victorious in unilateral encounters. Males rarely visited males to whom they
had submitted in aggressive encounters. On the few occasional visits that
occurred (e.g., to John), they approached in a submissive manner, cringing,
and with their tails between their legs. Taken together, Clark and John
visited the other three males 93% of the time while they were, in turn,
visited only 32% of the time. The time the subjects spent with each other
provides additional data on this point. One gets the impression that Clark
and John visited others frequently because they had nothing to fear. The
contrary seems to hold for the infrequent visits of the other three males.
Interestingly, Clark and John almost always visited each other and nearly
always engaged in mutual aggresision. However, neither of them was ever
clearly victorious over the other. Among the other three males, Eddie never
visited Broadus, but Broadus always visited Eddie and on every occasion they
assumed an aggressive posture with each other. Eddie backed down in three
of these encounters.
Some pairs, although in frequent contact, were conspicuous for the
absence of aggressive interactions. Clark was never aggressive to Eddie nor
was John ever aggressive to Broadus. Ken and Broadus were aggressive to
each other only once in I7 encounters. This is reminiscent of the "intrasex
loyalties" in wolves that GINSBURG (I965) writes about.
The general pattern and direction of aggressive behavior observed substantiates previous casual observations made on the dominance relationship
among these 5 males. Clark and John clearly dominated in all encounters
with the other males but they "fought" to a draw in frequent encounters
between themselves. The other males were rarely aggressive to each other
and no single male dominated any other.
NORMATIVECOMPARISONS
Although this paper has dealt primarily with the individual differences
stressed in preceding sections, some interesting normative information can be
obtained from a comparison of the performance of various test combinations
or groups on general measures of attraction such as the percentage of days
the tethered animal was visited and the total test time the free animal spent
with the restricted one. These data are presented in Table I5. As might be
INTERINDIVIDUAL
ASSOCIATIONS IN DOGS
29I
expected, heterosexual groups containing an estrous female scored highest
on both measures, with the M-EF group initiating more contacts and for a
longer period of time than its counterpart group, EF-M. Viewed as a group,
esitrous females visited nonestrous females nearly as often as they visited
males. However, they spent less time with the former. The lowest groups on
both measures were composed of roving nonestrous females.
TABLE I 5
Group comparisons for the measures, percentage of days the roving dog
visited the tethered dog and the percentage of total time spent in the circle
Groups
Per cent
Visits
Per cent
Total Time
M-EF
EF-M
M-NEF
EF-NEF
93
76
75
74
49
35
i6
M-M
68
NEF-NEF
NEF-EF
NEF-M
42
55
35
I5
3I
8
6
II
DISCUSSION
The observation that some bitches in physiological estrus mate less readily
with some males than others suggest that female dogs enjoy a higher level
of sexual freedom from ovarian hormones than was previously thought.
Carnivores in general have usually been classed with lower mammals such as
rodents with respect to the complexity and modifiability of an individual's
sexual behavior pattern. BEACH (1947) pointed out that sexual activation
and performance in lower mammals depends heavily on gonadal hormones,
whereas in primates hormonal control is not as rigid, and a considerable
degree of sexual responsiveness and flexibility is permitted in the absence
of secretions from the reproductive glands. For example, a close relationship
between high levels of ovarian hormones and sexual receptivity is the rule in
rats and guinea pigs, while in the rhesus monkey and the chimpanzee copulation is not always restricted to the female's fertile period. Under laboratory
conditions, mating may occur at any stage in the female's reproductive cycle
(TINKLEPAUGH,
I933;
YERKES,
I936;
YERKES & ELDER,
I936;
MICHAELS,
I965; KUEHN, I965), thus indicating that the female's sexual responsiveness
is not completely dependent on ovarian hormones. The sexuality of the bitch
Behaviour XXIX
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292
BURNEY J. LE BOEUF
is also influenced by non-hormonal factors but in d different way. The
bitch copulates only when levels of estrogen are high, but under these
conditions she may display preferences and aversions in her choice of males.
Selective behavior in mating adds a degree of flexibility to the behavior of
dogs which, as far as we know, is lacking in other lower mammals such as
the rat. Therefore, the present evidence makes it appear that the dependence
of sexual activity upon ovarian hormones in a carnivore, the dog, is less
pronounced than in rodents but stronger than in primates.
Certain definitional problems are created by selective mating tendencies of
the bitch. The commonly used dichotomy of classifying the bitch as
"receptive" or "not receptive" does not hold because receptivity is not a
general female state applicable to all males. The female may be receptive
to one male and not to another. This state of affairs may create problems for
the breeder who has to differentiate between a female that is not yet in
estrus and one that is in estrus to other males but not to the one with which
she is being tried.
The present study does not explain the formation of mating preferences,
however, it appears that their establishment does not depend on prior copulatory experience since some females exhibited preferences during their first
estrous period (BEACH & LE BOEUF, in press). Preferences do not seem to
be directly related to the dominance relationship among males, as the latter
was defined in this study. One of the two most aggressive males, John, was
readily acceptable to all females while the other, Clark, was not. The circumstances in which the animals develop may be very important. In the present
study, all Ss were reared together from weaning to the time observations
began. It is possible that the experience gained during development is necessary for the establishment of associations which appear as mating preferences
in adults.
It is worthwhile to stress the fact that the present observations were made
on one group of dogs. The sample size was small, one breed was studied,
and pairs of animals were tested briefly under restricted circumstances. These
considerations limit the generalizations that can be made, particularly with
regard to the day-to-day behavioral relevance of the observations.
SUMMARY
Interindividualbehavior in a group of dogs reared together in a large field was
studied to determinewhether social and sexual interactionswere more frequent in some
pairs than in others. The experimental setting was designed to maximize the display of
individual sympathies and antipathies.
The basic test provided a situation in which behavioral interactionsbetween a pair of
animals was contingent on one animal approachingthe other. One subject was restricted
INTERINDIVIDUAL
ASSOCIATIONS
IN DOGS
293
by a tether to a circular area with a diameter of approximately I2 feet while the other
subject, the roving animal, was released into the outdoor field for 5 minutes, the duration
of each test. Measures of association and a descriptionof behavior were made and then
the roles of each subject were reversed. Test combinationsconsisted of paired females,
paired males and heterosexual pairs. Females were observed before, during, and after
they were in behavioral estrus.
Members of the opposite sex were most attracted to each other when the females
were in estrus. However, all females were not equally attracted to all males. Three of
four females showed preferences for some males over others. A preferred male enjoyed
several advantages over nonpreferred males: (a) he was most frequently sought and
solicited by the estrous female and she spent more time with him, (b) he was permitted
to mount the female earlier in her estrous period, more frequently per day and, on more
days, and (c) he was rarely prevented from investigating or mounting the female by
being growled or barked at or by being bitten. Nonpreferred males were consistently
rejected in this manner. One of the 5 males was readily accepted by all females.
Otherwise, males preferred by one female were not uniformly preferred by the rest of
them. In one case, a male preferred by one female was most frequently rejected by
another. One female was equally receptive to all males.
The preferencesand aversions revealedby these subjects were evident the first time the
females came into estrus and in subsequentestrous periods, whether natural or induced
by exogenous hormones. These results were interpreted as indicating that sexual
receptivity in the bitch is not completely dependenton ovarian hormones.
Interactionsbetween females were infrequent and brief as comparedto those between
two males or heterosexual pairs containing an estrous female. Strong individual
associations between female pairs were not evident.
Male-male interactions commonly involved elements of ritualized aggression while
female-female interactions did not. The response of one male to another depended in
part on which one had previously retreated in an aggressive encounter with the other.
The submissive male in these stereotyped encounters was frequently visited, but he
himself, rarely approachedothers.
Some males preferred the company of some males to others. Members of a pair
sympathetic to each other made frequent contacts of long duration and showed no
aggression to each other.
REFERENCES
ASDELL,
S. A. (I966). Dog Breeding. - Boston: Little, Brown and Company.
BEACH,
F. A. (I947). Evolutionarychanges in the physiologicalcontrol of mating behavior
in mammals.
-
Psychol. Rev. 54, 297-3I5.
(I96I). Sex differences in the physiologicalbases of mating behavior in mammals.
- In: ALEXANDER SIMON (Ed.), The physiology of emotions. Illinois: Charles C.
Thomas.
& LE BOEUF, B. J. (in press). Mating preferences in female dogs. - Anim Behav.
BUYTENDIJK, F. J. J. (1936). The mind of the dog. - Boston: Houghton Mifflin.
DARWIN, C. (I872). The expression of the emotions in man and animals. - London:
J. Murray.
ENDERS, R. K. (I945). Induced changes in the breeding habits of foxes. - Sociometry
8, 53-55.
FULLER, J. L. & DuBuIs, E. M. (I962). The behaviourof dogs. - In: E. S. E. HAFEZ
(Ed.), The behaviorof domesticanimals. Baltimore: Williams and Wilkins Company.
GINSBURG, B. E. (I965). Coactionof genetical and nongeneticalfactors influencing sexual
behavior. - In: F. A. BEACH (Ed.), Sex and behavior. New York: John Wiley and
Sons, Inc.
294
BURNEY
J. LE BOEUF
GRAHAM,R. P. (ig6i). The mating and whelping of dogs (3rd ed.). -
London: Poptilar
Dogs.
HANCOCK,J. L. & ROWLANDS,I. W. (i949). The physiology of reproductionin the dog.
- Vet. Rec. 6i, 77I-779.
A. E. (I960). Reproductionin the dog. - Baltimore: Williams and Wilkins.
HARROP,
KINSEY, A. C., POMEROY,
W. B., MARTIN, C. E. & GEBHARD,P. H. (1953). Sexual
behavior in the human female. - Philadelphia: W. B. Saunders Company.
KUEHN,R. E. (I965). Mating behavior in adult Macaccamulatta. - Paper presented at
the AAAS meetings in Berkeley, California, December.
LE BOEUF, B. J. (I967). Heterosexual attraction in dogs. - Psychon. Sci. 7, 313-314.
LORENZ,K. Z. (1952). King Solomon'sRing. - New York: Thomas Y. Crowell.
(953). Man meets dog. - Baltimore: Penguin.
MICHAELS, R. P. (I965). Endocrine factors in sexual and grooming behavior in rhesus
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Zurich, Switserland, September.
London: Oxford Univ. Press.
TINBERGEN, N. (I95I). The study of instinct. TINKELPAUGH,
0. L. (1933). Sex cycles and other cyclic phenomena in a chimpanzee
during adolescence,maturity and pregnancy.- J. Morph. 54, 52I-546.
L. F. (I947). How to breed dogs (revised). - New York: Orange Judd
WHITNEY,
Publishing Company.
YERKES,R. M. (1936). A chimpanzeefamily. - J. genet. psychol. 48, 362-370.
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RflSUMP:
La conduite individuelle dans un groupe de chiens eleves en meme temps dans un
grand champ a ete etudiee pour determinersi les interactions,tant sociales que sexuelles,
etaient plus frequentes chez certains couples que chez d'autres. L'atmosphere pour
l'experience etait organisee pour deployer au maximum les sympathies et antipathies
individuelles.
L'experience de base donnait une situation oiu la conduite entre un couple d'animaux
etait contingente d'un animal approchantl'autre. Un sujet etait retenu par une chaine
dans un endroit circulaire d'un diametre de 4 metres environ, pendant que l'animal libre
etait lache dans un champ exterieur pour la duree de chaque experience qui est de cinq
minutes. Des mesures d'association et une description de la conduite ont ete faites et
ensuite le r6le de chaque sujet etait inverse. Des experiences combinees ont ete faites
avec des paires de femelles, des paires de males, et des paires heterosexuelles. Les
femelles etaient sous surveillance,avant, pendant et apres leur oestrouse behaviorale.
Les sujets de sexe oppose etaient attires l'un par l'autre lorsque les femelles etaient
en oestrouse. Cependant,toutes les femelles n'etaient pas attirees de maniere egale par
tous les males. Trois des quatre femelles ont montre une preference pour certains
males plut6t que pour d'autres. Un male prefere avait plusieurs avantages sur les
males delaisses:
etait plus frequemment recherche et sollicite par la femelle oestrouse et elle
a) -il
restait plus longuement avec lui.
etait autorise a couvrir la femelle plus t6t dans sa periode oestrouse, plus
b) -il
souvent dans une journee et pour plus de jours.
il etait rarement empeche par des grognements ou aboiements ou par des coups
c)
de crocs, d'etudierou de couvrir la femelle. Les males delaisses etaient rejetes de
cette maniere. Un des cinq males etait toujours accepte par toutes les femelles.
D'autre part, les males preferes par une femelle n'etaient pas uniformement preferes par toutes. Dans un cas, un male prefere par une femelle etait plus fre-
INTERINDIVIDUAL
ASSOCIATIONS
IN
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295
quemment rejete par une autre. Une des femelles etait receptive a tous les males
de maniere egale.
Les preferences et aversions revelees par ces sujets etaient evidentes la premiere fois
ou les femelles etaient en oestrouse et pendant les periodes oestrouses, naturelles ou
provoquespar des hormones exogenes. Ces resultats etaient interpretes comme indiquant
que le comportementsexuel de la chiennen'est pas completementdependantdes hormones
ovariennes.
Les interactions entre femelles etaient breves et peu frequentes, comparees a celles
de deux males ou de couples heterosexuels, comprenantune femelle oestrouse. De fortes
associations entre paires de femelles n'etaient pas probantes.
Les interactions de male a male engageaient generalement des elements d'agression
rituelle, alors que les interactionsde femelle 'a femelle n'en engageaient pas. La reponse
d'un male a un autre dependait en partie de celui que s'etait retire auparavant lors
d'une rencontre aggressive avec l'autre. Le male soumis dans ces rencontres stereotypees
etait souvent recherche, mais lui-menmeapprochait rarement les autres sujets.
Certains males preferaient la compagnie de certains males a d'autres. Les membres
d'une mtemepaire sympathisantentre eux avaient des contacts frequents de longue duree
et ne montraientaucune agression l'un envers l'autre.