Helodermatidaes of the United States
Gila Monsters are heavy-bodies, with short stout legs and a thick tail. With an abundance of food the tail becomes fat. During periods of scarcity, the tail may lose up to 20% of its nulk as the stored fat is used up. On the back and head are non-overlapping bead-like scales of shiny black, pink, or yellow. The scales contain osteoderm, a sort of bony armor.
Gila Monsters are venomous carnivores that seem to rely more on taste and smell to locate their quarry than on vision. They have been observed tracking their prey by tasting the ground with their long thick tongues. Their venom causes great pain, but rarely human death. it is the persisitant grip of a Gila Monster's jaw that is the single most important reason for handling these lizards carefully.
There is only one specie of Helodermatidae in the U.S.
Found from extreme southwestern Utah, southern Nevada and adjacent California, south through southern Arizona and southwestern New Mexico to Mexico.