Gila monster
This lizard has venomous glands located in the bottom jaw, with channels toward the teeth, which are striated to facilitate the entry of the venom into the victim's wound. This is why the Gila monster bites onto its prey with such strength. The bite is rarely mortal to humans.
They spend most of the year inactive, hidden in holes, often abandoned burrows. In the summer, they come out to seek a partner, taking advantage of this time to eat as much as possible, storing fat in their tails, which lets them survive all winter.
Breeding program
Natural habit
North Mexican and the southwest of the United States.

- Distribution / Resident
- Breeding
- Wintering
- Subspecies
Risk level
- Extint
- Extint in the wild
- Critically endangered
- In Danger
- Vulnerable
- Near threatened
- Minor concern
- Insufficient data
- Not evaluated
Taxonomy
Physical characteristics
Biology
Reproduction
Biology
This lizard, despite what the name may suggest, is not an enormous, savage animal, but rather a chubby lizard with rough skin, a thick tail and short legs, with bright yellow or orange spots over black.
It inhabits deserts and arid rocky mountains up to altitudes of 1500 metres.
Its diet consists of small vertebrates, eggs, worms, insects and dead animals.
Female Gila monsters lay two to 15 eggs, normally in July or August. The incubation period varies depending on temperature, but babies are usually born around May.
They are 12 to 18 cm at birth, weighing 35 to 40 grams and attain adult size in one to three years, and can live for some 20 years.
The high temperatures and lack of humidity that they can support in their arid habitat make them animals of the twilight and night, and they tend to spend most of the time hiding in holes they dig into the ground. Indeed, they spend most of the year inactive, hiding away in holes. In the summer, they come out to seek a partner, taking advantage of this time to eat as much as possible, storing fat in their tails, which lets them survive all winter.
They have venomous glands located in the bottom jaw, with channels to the teeth, which are striated to facilitate the entry of the venom in the victim's wound. This is why the Gila monster bites onto its prey with such strength. The bite is rarely mortal to humans. They smell the presence of prey, as their sense of smell is highly developed, and also by touch, where their tongues are great detectors.
The loss and degradation of its habitat from agriculture, livestock and urbanisation have shrunk populations and they are now scarce in many regions in which they were abundant until recently, which is why the IUCN has it catalogued as Almost Endangered on its Red List of animals in danger of extinction.
The Barcelona Zoo participates in the EEP for this species and has successfully bred them at its facilities.