Animal Facts

Gila Monster

Scientific Name: Heloderma suspectum

Fast Fact:

The Gila monster is one of two venomous lizards in the entire world!

Gila Monster

Along with its relative the Mexican Beaded Lizard, it has a poisonous bite that is used for self-defense. Although generally not fatal to humans, a Gila monster’s bite can still be extremely painful. There are two subspecies, the reticulate Gila monster and the banded Gila monster, which differ mainly in where they live.

STATUS: According to the International Union for Conservation of Nature (IUCN), the Gila monster is listed as Near Threatened. They are sometimes killed out of fear of their poisonous bite; however, the most likely reason for their decline in population comes from habit loss due to overdevelopment. There is also a small, illegal pet trade for Gila monsters, although they are protected by state laws.

HABITAT: Gila monsters are found in the southwestern United States and northwestern Mexico. They live in arid regions, although they prefer to stay near moisture. They are found in succulent desert areas as well as canyons and arroyos. Gila monsters spend a lot of time in underground burrows as well. During the winter they hibernate to escape the cold desert conditions, and during the summer they spend midday underground to avoid the harsh desert sun.

DIET: The primary food source of the Gila monster is eggs of birds, lizards, snakes, turtles, and tortoises. They will also occasionally dine on small mammals, birds and lizards. A Gila monster will smell out its prey by flicking its tongue, which provides it with an excellent sense of smell. Gila monsters tend to go long periods without consuming any food, so they will often fill up when they choose to eat. A young Gila monster can consume half of its own bodyweight in one meal, while an adult can consume about 35% of its bodyweight. After eating such large quantities of food, they can store a considerable amount of fat in their tails. This fat will provide them with energy in the future.

PHYSICAL CHARACTERISTICS: A Gila monster is distinguished by its yellow, pink, and black beaded scales. Its broad head and neck are generally black, along with its legs and clawed feet. The black and pink or yellow will form stripes or spots along the body, usually followed by a striped tail. Its body is very large and stout, accompanied by a short, fat tail. Adult Gila monsters will grow to be about 20 inches long. This stocky body does not allow it to sprint very fast, which is part of the reason they are not considered very threatening to people. However, Gila monsters do have great endurance, particularly the males. This may be in part because the males have been known to wrestle with each other for hours, competing for dominance and a better chance at reproductive success.

Living Fossils

The scientific name heloderma comes from the Greek roots meaning “studded skin.” The Gila monster’s beaded skin is quite unique in the present time, but it was common among dinosaurs millions of years ago. The ancestors of Gila monsters have been traced all the way back to the Cretaceous Period. Despite some evolutionary modifications, not much has changed between those lizards and the Gila monsters surviving today. For this reason, Gila monsters are often seen as living fossils, giving scientists an up close and personal look at life in the time of the dinosaurs.  

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