Eastern Collared Lizard
named because of the dark lines around its neck, the Eastern
Collared Lizard (Crotaphytus collaris collaris) is probably
better known by Oklahomans as the “mountain boomer.”
A brightly colored specimen, the Eastern Collared Lizard may be identified by its tan, yellow or green shades, and the small light spots scattered over its upper body. Females are yellowish-tan with only faint spots covering the body. Both possess the dark brown, irregularly shaped “collar,” and adults of both sexes typically measure 8 - 14 inches in length.
A diurnal species, the Eastern Collared Lizard is especially active in warm, sunny weather. These lizards prefer an air temperature of 73° - 93° F, and as such, are active from April through September, though young lizards may remain active through October.
Mountain boomers are often observed sunning on rocks and boulders, yet quickly retreat to the security of a crevice if approached. If threatened in an open area, it is capable of running very fast to escape. In such a situation, the lizard may run on its hind legs with the forward part of the body held upright. Each lizard defends a home territory by chasing away other collard lizards when that territory is violated.
As they are cold-blooded reptiles, the Eastern Collared Lizard must find a burrow to spend the winter months in. Such burrows are usually found under large rocks, 8 - 12 inches deep. During their active months, mountain boomers live among limestone, sandstone or granite glades, and prefer those facing south or southwest for maximum exposure to sunlight.
A brief courtship and mating season extends from mid-May to early June. The males court by displaying their brightly colored throat and body, while prancing around the female. Twenty days after breeding, the female will lay from 2 - 21 creamy-white leathery eggs in a burrow beneath a large rock. Hatching 2 - 3 months later, the young will have dark bands with yellowish crossbars, and average 3 - 4 inches in length.
Eastern Collard Lizards eat a variety of insects including grasshoppers and beetles, but also eat spiders, small snakes and lizards. While their diet renders them beneficial to humans, they are subsequently preyed upon by large snakes, hawks and roadrunners.
Common throughout the southwestern United States, the mountain boomer probably received its nickname from settlers who saw the lizards sunning on rocks, while hearing the barking of a frog. In reality, the Eastern Collared Lizard is voiceless.