Description: This is one of only two venomous lizard species in the world (the other is the Mexican beaded lizard, Heloderma horridum). Gila monsters are large and stout lizards with a short fat tail (maximum length of 56 centimeters). Their scales are beaded yellow, pink, and black. The broad head, chin, and neck are black, as well as the legs and feet. The black eyes have a round pupil. The ear opening is a narrow oblique or ovoid slit. The limbs of the lizard are stout and have heavy claws.

Habitat: The Gila monster can be found in arid areas. These areas usually contain scattered cacti, shrubs, mesquite, and grasses. Rocky slopes, arroyos, and canyon bottoms (mainly those with streams) support populations in Arizona.

Range: The Gila monster ranges from the extreme southwestern Utah, southern Nevada, and adjacent San Bernadino County, California, southeastrward through west and south Arizona and southwestern New Mexico. It ranges south into Mexico through Sonora to northwestern Sinaloa. It ranges from sea level to 1,500 meters in altitude.

Found in these States: AZ | CA | NV

Diet: The Gila monster's diet consists of a variety of objects: small mammals (young rabbits, mice and squirrels), birds, lizards, and eggs (of birds, lizards, snakes, turtles, and tortoises). The Gila monster has the capability to consume large amounts of food at one time (young can consume 50% of their body weight at a single feeding, adults can consume 35%). This is advantageous in an envirnoment in which finding prey at regular intervals may be difficult. Prey are rarely envenomated, which indicates that venom is used mainly for defense. Prey are detected by olfaction (the sense of smell). The Gila monster, like most snakes, uses its tongue for olfaction.

Reproduction: Mating, which is usually in May, begins with the male tongue-flicking to seek a females's scent, while rubbing his cloaca on the ground. When a male locates a female, he lies by her and rubs his chin on her back and neck while holding her with his hindlegs. If a female objects to the male, she will try to bite him while crawling out from underneath. If receptive, she raises her tail. The male then moves his tail under hers, bringing their vents into contact. Copulation lasts from 30 minutes to an hour. The female lays her eggs (1-12) in an underground cavity, normally in July or August. Incubation lasts on average about ten months, and the young to hatch and emerge the following May. The process (fertilization through emergence) lasts about a year.

Venom: The venom of a Gila monster is normally not fatal to healthy adult humans. No reports of fatalities have been confirmed after 1930, and the rare fatalities recorded before that time occurred in adults who were intoxicated by alcohol or had mismanaged the treatment of the bite. The Gila monster can bite quickly, and may not release the victim without intervention. If bitten, the victim may attempt to fully submerge the lizard in water, pry the jaws open with a knife or stick, or physically yank the lizard free. While pulling the lizard directly increases risk of severe lacerations from the lizard's sharp teeth, it may also mitigate envenomation. Symptoms of the bite include excruciating pain, edema, and weakness associated with a rapid drop in blood pressure.

Status: The lizard is often killed because it is venomous. The Gila monster is legally protected in all states in which they are found.

Listed as Near Threatened because this species is probably in significant decline (but probably at a rate of less than 30% over three generations), especially because of habitat loss throughout much of its range, thus making the species close to qualifying for Vulnerable under criteria A2, A3 and A4.

In 1952, the Gila monster became the first venomous animal to be given legal protection. They are now protected in all states of their distribution. International trade in the species is regulated under Appendix II of CITES.

Taxonomy: