Gila monster Gila monster The Gila monster ("Heloderma suspectum", ) is a species of venomous lizard native to the southwestern United States and northwestern Mexican state of Sonora. A heavy, typically slow-moving lizard, up to long, the Gila monster is the only venomous lizard native to the United States and one of only two known species of venomous lizards in North America, the other being its close relative, the Mexican beaded lizard ("H. horridum"). Although the Gila monster is venomous, its sluggish nature means it represents little threat to humans. However, it has acquired a fearsome reputation, and is sometimes killed despite
Mexican beaded lizard with large specimens exceeding . Maximum weight known is Although males are slightly larger than females, the lizards are not sexually dimorphic. Both males and females are stocky with broad heads, although the males' tend to be broader. The beaded lizard's scales are small, beadlike, and not overlapping. Except for the lizard's underside, the majority of its scales are underlaid with bony osteoderms. Their base color is black and marked with varying amounts of yellow spots or bands, with the exception of "H. alvarezi", which tends to be all black in color. The beaded lizard has a short tail which