Gila monsters (Heloderma suspectum) are native to the southwestern United States and the northwestern Mexican state of Sonora.

At a length of up to two feet and a maximum weight exceeding five pounds, the Gila monster is the largest lizard native to the United States.

Although Gila monsters are venomous, they represents little threat to humans because of their sluggish nature. Their top speed is only 1.5 miles per hour (2.4 kilometers per hour).

Gila monster venom is about as toxic as that of a western diamondback rattlesnake, but a relatively small amount of venom is introduced in a Gila bite as these lizards chew the venom in through grooves in their teeth rather than injecting it through fangs like venomous snakes.

In the Old West, pioneers believed a number of myths about the Gila monster, including that it was immortal, that it's breath was toxic, and that, if bitten by a Gila monster, it would not let go until sunset or until it heard thunder.

It has been suggested that Gilas can consume all the calories they need for a year in three or four large meals. Nevertheless, they will feed whenever they comes across suitable prey.

The Gila monster's diet consists of a variety of food items, including small mammals such as rabbits, mice, and ground squirrels, as well as small birds, other lizards, frogs, insects, and the eggs of birds, lizards, snakes, turtles and tortoises.

Gila monsters spend 90% of their time underground in burrows or rocky shelters.

Gila monsters have a home range of about 1 square mile (1.6 square kilometers).

They get their name from Arizona's Gila River basin, where they were first discovered.