Scientific Name Heloderma suspectum Other Names Gila monster Range Southeastern California, southern Nevada, southwestern Utah, Arizona and New Mexico Habitat Desert and semi arid plains Average Size Length: 14 – 20 in. Weight: 2 – 5 lbs. Description Large lizard with black and orange to pink coloring, a stout body and a large tail. Lifespan In the wild: Up to 20 years In captivity: 30 years Diet In the wild: Small mammals, birds, eggs and rodents In captivity: Mice Incubation 9 – 10 months Sexual Maturity 2 – 3 years of age Clutch Size 2 – 12 eggs Predators Birds of prey, bobcat, foxes and humans Population Status Vulnerable Behavior 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 humans. 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. Conservation 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 Gila Lizard Heloderma suspectrum Reptile 3930 West Land Park Dr., Sacramento, CA The Sacramento Zoological Society 2 2 8 5 9 A C , o t n e m a r c a S , . r D k r a P d n a L t s e W 0 3 9 3 saczoo.org T: 916-808-5888 F: 916-264-7385 E: [email protected]