Gila Monsters and Beaded Lizards
The family Helodermatidae is represented by only two species; the Gila Monster (H. suspectum) and the Beaded Lizard (H. horridum). They are the only venomous lizards in the world and arguably the most recognizable.
The genus name Heloderma is of Greek origin meaning "studded skin". This description refers to the hard, round osteoderms which cover the entire dorsal surface of the body giving the skin a distinctive bead-like appearance. The head is large and broad, the body is heavy with a sausage-like tail and powerful short legs and long claws. The tail of this lizard is a fat storing organ that will be thin with an undernourished animal. In both species the ground color is black, accented with irregular pink, orange or yellow markings, some quite vivid and contrasting in appearance. Some observers describe the color pattern of the Gila Monster as being a reticulated pattern of black blotches on a pink, orange or yellow background.
Gila Monsters and Beaded Lizards are primarily nest robbers feeding on rodents, ground dwelling birds and bird eggs, and the eggs of other reptiles. They are also known to be scavengers. They are highly secretive animals which spend a great deal of time in underground burrows. Gila Monsters in particular are known to spend as much as 95% of their lifetime in hiding.
Only the Gila Monster (H. suspectum) is found in the United States. Both the Gila Monster and the Beaded Lizard (H. horridum) are native to Mexico. These animals should be approached with caution in the wild and not handled . They can inflict a venomous bite which is seldom fatal to humans, but certainly very painful. They are also protected by law in most of their natural range.