Reptiles
Collared Lizard
Crotaphytus collaris · also called eastern collared lizard, common collared lizard, mountain boomer
The collared lizard is the most dramatic lizard in the rocky country of the American Southwest: a foot-long animal in electric blue-green with a golden head, two black collar bands, and a habit of standing up and sprinting on its back legs like something out of the Triassic.
Overview
Crotaphytus collaris lives on rocky hillsides, limestone glades, and boulder fields from Missouri west to Utah and Arizona and into Mexico. Breeding males are brilliant blue-green with a yellow head; females are tan and develop orange bars when carrying eggs. It has a big head and a hard bite.
The bipedal sprint
At speed the collared lizard rears onto its hind legs, using the tail as a counterweight, and runs at around 26 km/h, bounding between rocks. Few lizards do this as a matter of routine.
A lizard that eats lizards
It is largely a predator of other lizards — including smaller collared lizards — plus big insects, hunted from a prominent basking rock where it also displays with head-bobs and push-ups. The old Ozark name “mountain boomer” rests on a myth; the lizard is silent.
Status
The collared lizard is Least Concern and stable. In the Missouri Ozarks, where fire suppression had isolated populations on overgrown glades, prescribed burning and reintroductions have brought it back — a well-known local conservation success.
Collared Lizard: common questions
Why does the collared lizard run on its hind legs?
It is a fast, visual predator that lives among boulders and needs to cover open ground quickly, whether chasing a grasshopper or another lizard or fleeing a snake or a hawk. Rising onto the hind legs lengthens its stride, lifts the front of the body so it can see ahead, and lets the long tail swing as a balance and a rudder for sharp turns and leaps between rocks. Many lizards can manage a few bipedal steps when accelerating hard; the collared lizard is unusual in doing it routinely as a normal way of getting around its rocky terrain, which is why it is often compared to a miniature running dinosaur.
Are collared lizards aggressive?
Toward prey and rivals, yes. They are territorial, and a dominant male will chase, display at, and sometimes fight other males, while both sexes readily attack and eat lizards smaller than themselves, including juvenile collared lizards. Toward people they are not aggressive but they are not shy either; a collared lizard that cannot escape will face the threat, open its mouth, and deliver a genuinely painful bite with its heavy jaws, then hold on. Handled regularly in captivity they can calm down, but a wild one should be left alone.
What is a glade and why does it matter to this lizard?
In the Ozarks and similar regions, a glade is an opening in the forest where thin soil over bedrock supports desert-like plants and a community of reptiles and insects more typical of the Southwest, including the collared lizard. These glades were historically kept open by periodic fire. When fire was suppressed through the twentieth century, eastern red cedar invaded and shaded them out, and the collared lizard populations, unable to cross the closed forest between glades, became isolated and began winking out. Restoring prescribed burning has reopened the glades and, along with translocating lizards, allowed the animals to spread and mix again.
Do collared lizards make good pets?
They are kept by experienced reptile keepers and can do well, but they are demanding. They need a large, tall enclosure with a deep hot basking zone, strong UVB, a big temperature gradient, rocks to climb and bask on, and a diet of insects with occasional pink mice or other lizards for adults. They are active, alert, and best housed one to an enclosure because they will fight. Wild-caught adults rarely settle; captive-bred juveniles are the right choice. Their speed and their willingness to bite make them a watch-don't-handle animal for most keepers.