Common collared lizard
|Eastern collared lizard
|A common collared lizard in Taum Sauk Mountain State Park, Missouri|
The eastern collared lizard (Crotaphytus collaris), also called common collared lizard, Oklahoma collared lizard or collared lizard, is a North American lizard that can reach 8–14 inches (20–36 cm) in length (including the tail), with a large head and powerful jaws. They are well known for the ability to run on their hind legs, looking like small theropod dinosaurs. Found in Missouri, Texas, parts of Arizona, western states, and parts of Kansas, the collared lizard is the state reptile of the United States state of Oklahoma, where it is known as the mountain boomer. The name "collared lizard" comes from the lizards' distinct coloration, which includes bands of black around the neck and shoulders that look like a collar. It is a member of the collared lizard family.
These reptiles are often tamed and kept as pets. When born in captivity, they are quite docile and tolerant of interaction with humans. They are very active and predatory lizards, requiring a large amount of space to run. They prefer high temperatures, up to 105–110 °F (41–43 °C) at their basking spot and 80 °F (27 °C) elsewhere in their habitat during the day. Some collared lizards eat small amounts of fruit or vegetables, but most prefer a diet of insects. They will also consume vertebrate prey, including small mammals and other lizards. Like many reptiles, in captivity they must be provided a diet supplemented with extra calcium and a light source with a UVB radiation to reduce the risk of bone disorders.
The origin of the name "mountain boomer" is not clear, but it may date back to settlers travelling west during the Gold Rush. One theory is that settlers mistook the sound of wind in canyons for the call of an animal in an area where the collared lizard was abundant. In reality, collared lizards are silent.
Like many other lizards, including the frilled lizard and basilisk, collared lizards can run on their hind legs, and are relatively fast sprinters. Record speeds have been around 16 miles per hour (26 km/h), much slower than the world record for lizards (21.5 mph or 34.6 km/h) attained by the larger-bodied Costa Rican spiny-tailed iguana, Ctenosaura similis.
Collared lizards in the wild have been the subject of a number of studies of sexual selection. In captivity if two males are placed in the same cage they will fight to the death. Males have a blue-green body with a light brown head. Females have a light brown head and body.
- Hammerson, G. A., Lavin, P., Vazquez Díaz, J., Quintero Díaz, G. & Gadsden, H. (2007). "Crotaphytus collaris". IUCN Red List of Threatened Species. Version 2011.2. International Union for Conservation of Nature. Retrieved 16 February 2012.
- "Crotaphytus collaris (Say, 1823)". The Reptile Database. Retrieved 2012-02-16.
- Stebbins, R.C. 2003. A Field Guide to Western Reptiles and Amphibians, Third Edition. The Peterson Field Guide Series. Houghton Mifflin. Boston and New York. xiii + 533 pp. ISBN 0-395-98272-3. (Crotaphytus collaris, pp. 271-272 + Plate 27 + Map 85.)
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- Bonine, K. E.; Garland, Jr., T. (1999). "Sprint performance of phrynosomatid lizards, measured on a high-speed treadmill, correlates with hindlimb length". Journal of Zoology (London) 248: 255–265. doi:10.1111/j.1469-7998.1999.tb01201.x.
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- Drake, E. C. (1999). Information on the Collared Lizard.