Gila Monster and Mexican Beaded Lizard: Helodermatidae

These species spend about twenty-three hours of every day out of sight in burrows, within cracks in rocks, or in trees. When they do travel above ground, they wander about during the day looking for food or for mating partners, sometimes traveling more than 0.6 miles (1 kilometer). They also may come out in the evening. During the breeding season, the males of both species will fight one another, sometimes battling for two or three hours at a time. The male beaded lizards will arch their bodies and wrestle belly-to-belly until one comes out on top. The male Gila monsters wrestle by twisting the body to and fro. Courtship and mating occur in spring for the Gila monsters and in fall for the beaded lizards. Two to three months later, female Gila monsters lay two to twelve eggs, and female beaded lizards lay two to twenty-two eggs. Hatchling Gila monsters leave the nest the following spring in April, and hatchling beaded lizards appear in June or July as the wet season begins.