Gila Lizard.indd



Gila Lizard.indd
Heloderma suspectrum
Gila Lizard
Scientific Name
Heloderma suspectum
Other Names
Gila monster
Southeastern California, southern Nevada,
southwestern Utah, Arizona and New Mexico
Desert and semi arid plains
Average Size
Length: 14 – 20 in.
Weight: 2 – 5 lbs.
Large lizard with black and orange to pink
coloring, a stout body and a large tail.
In the wild: Up to 20 years
In captivity: 30 years
In the wild: Small mammals, birds, eggs and
In captivity: Mice
9 – 10 months
Sexual Maturity
2 – 3 years of age
Clutch Size
2 – 12 eggs
Birds of prey, bobcat, foxes and humans
Population Status
Gila lizards vary their activity periods depending upon the season. In
the spring and fall, they are mostly diurnal and in the summer they are
nocturnal. They are rarely seen as they spend only a few hours above
ground each day searching for basking sites, food, breeding dens or
mates. It is estimated that these lizards spend up to 95% of their time
underground. Because they eat infrequently, as little as five to 10 times a
year, they eat large meals that may equal a third of their body weight. Their
acute sense of smell is able to detect eggs up to six inches underground.
Although generally slow and sluggish in an effort to conserve their energy,
Gilas can move rapidly when hunting or threatened.
Rather than injecting venom into their prey with fangs, the Gila lizard has
teeth that are grooved to allow the toxin to flow into the wound as it chews
on its prey. The venom is a neurotoxin, very similar in toxicity to that of a
rattlesnake, but it is produced in such small amounts that it is rarely fatal to
As with most desert lizards, the large tail serves as a storage facility for fat
and water than can be metabolized in time of need. Gila lizards hibernate
from November to January or February, when a healthy supply of stored fat
is needed for sustenance.
Reproduction and Breeding
Breeding season for this species starts in spring, with males physically
battling for mating rights. Their twisting and wrestling matches can last
for hours at a time. Gila lizards are immune to their own venom, so biting
during this process is not fatal. Actual mating begins in late spring and
toward the beginning of summer, with egg laying in fall and winter. The
female lays her eggs in sandy soil, under rocks or in abandoned mammal
burrows then covers them with nearby sand. Like most reptiles, neither
parent provides any parental care to the offspring. The hatchlings are able
to bite and dispense venom immediately and are fully able to survive on
their own. Although not fiercely territorial, the youngsters leave to find their
own space by the following spring.
There are many current conservation concerns for Gila lizards, with urban
sprawl, loss of habitat, increased human activities in the desert, and the pet
trade topping the list. In addition, they are persecuted and killed for their
The Sacramento Zoological Society
930 West
West L
and Park
Park Dr.,
Dr., S
acramento, C
A 95822
T: 916-808-5888 F: 916-264-7385 E: [email protected]
fierce reputation although there has never been a documented human fatality related to this species.
Historically, humans have long had a mixed relationship with the Gila lizard. Some Native American tribes believed they had
supernatural powers of healing, while others believed they had evil tendencies and were responsible for sickness and death. Many
forms of Native American art were inspired by the design and coloration of the Gila lizard.
Gila lizards are protected by law in all areas of their range and special permits are required for removing them from the wild. In 1952,
they became the first venomous animal to receive legal protection.
Amazing Facts
The Gila lizard is one of only two venomous lizards. The other is its cousin, the Mexican beaded lizard!
There are two sub species of Gila lizard!
A synthetic form of the substance found in Gila saliva is now being used to treat diabetes!
Gila Lizard
The Sacramento Zoological Society
930 West
West L
and Park
Park Dr.,
Dr., S
acramento, C
A 95822
T: 916-808-5888 F: 916-264-7385 E: [email protected]

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