Gila Monster
Heloderma suspectum

The Gila monster inhabits the southwestern United States and northern Mexico, including southwestern Utah, Nevada, Arizona, southern New Mexico, and as far south as Sinaloa, Mexico. Its range spans desert lowlands to elevations of around 6,400 feet (1,950 m). This species thrives in a variety of habitats, from arid desertscrub and grasslands to the lower reaches of Great Basin Conifer and Madrean Evergreen woodlands. It is most commonly found in rocky drainages, bajadas, and mountain slopes, often seeking shelter in burrows, rock crevices, or dense vegetation. A sluggish and reclusive reptile, the Gila monster spends most of its time in underground shelters, emerging only for short periods, totaling about three to four weeks annually. It is diurnal during cooler months in spring and fall, becoming nocturnal during hot summer nights, especially following warm rains. During winter, it hibernates in burrows on sunlit, rocky slopes, often in communal retreats. Though not aggressive, it may bite if provoked, delivering venom through grooves in its teeth. This carnivorous lizard primarily preys on eggs (avian and reptilian), nestling birds and mammals, lizards, insects, and carrion. It relies on its powerful jaws to crush prey. The Gila monster’s ability to store fat in its tail allows it to survive long periods without food, with as few as four or five meals sustaining it for a year. Mating occurs from mid-spring to early summer, with males engaging in combat for access to females. Clutch sizes range from 2 to 12 eggs, typically laid in July or August. The eggs hatch in the fall, but hatchlings remain in the nest until the following spring. Females usually reproduce biennially. The Gila monster belongs to Helodermatidae, the sole family of venomous lizards. Its venom, delivered through chewing, is painful but rarely fatal with medical attention. This species is legally protected across its range, with strict prohibitions on harassment, collection, or harm. Captive Gila monsters have been documented to live over 25 years. Its vivid coloration likely serves as both warning and camouflage in its native habitat.