Crotaphytus collaris collaris

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Geographic Range

Eastern collared lizards are found in areas between Kansas to northeastern Mexico, primarily in the central plains region, hilly or canyon lands which make up this particular part of the United States. In Texas, this species is found in the central to western regions (Bartlett and Bartlett, 1999).

Habitat

These lizards are found in a variety of habitats, ranging from arid areas with large rocks which are good for basking to hardwood forest regions. More frequently, however, they are found in hilly regions. (Bartlett and Bartlett 1999).

Physical Description

These are relatively large lizards, with slender necks, large heads and long tails. There is a definite dimorphism in this species; males are larger and are often very brightly colored with yellow and orange bodies. (Behler 1979)

The most noticeable characteristics of these lizards are found in the two black collars that run from the arms to the neck of the animal. Furthermore, there are usually six dark cross bands which run across the lizard's back (Dundee and Rossman 1989).

The bodies are usually covered with small white spots. Also, the scales on the lizard's body are granular, while the tail scales appear to be slightly larger. (Behler, 1979).

Reproduction

These lizards, like most other lizard speciess, are oviparous. They lay between 2-11 eggs in each clutch every yera. Under normal circumstances, breeding begins in May and continues through June. The eggs are ordinarily laid during July. In order to protect the eggs from predators, the lizards will bury them in loose sand and beneath the stones that they usually bask on (Bockstanz, 1998).

Behavior

Eastern collared lizards are diurnal, but remain wary of strangers who might get too close to them. While they will most often run in the presence of danger, they sometimes become quite aggressive and feisty (Baird and Timanus 1998).

When fleeing, the lizard will lift its body and tail, and run on its hind legs. The lizards will hid under rocks or trees nearby until they feel safe to come out again.

They also prefer limestone rocks and ledges on which to bask for thermoregulation. This gives them the perfect vantage from which to observe any threatening intruders (Firth, 1980).

Food Habits

The eastern collared lizard is an active predator. It feeds on a variety of arthropods and small lizards. While food sources vary, these lizards seem to prefer large grasshoppers for nutrition. In addition, spiders, moths, and beetles are also eaten. When the lizard preys on other lizards, it will kill them by crushing their skulls. It must be noted that while these lizards were previously thought to be very cannibalistic, they are now thought to be less so, only killing other conspecifics when necessary (Sugarman, 1988).

Economic Importance for Humans: Positive

The lizards help to stabilize the grasshopper, beetle, and moth populations by preying on them (Behler 1979).

Conservation Status

No special status at the present time. They are fairly well distributed. However, they might not often be seen because of their nervous nature (Bartlett and Bartlett 1999).

Other Comments

These lizards are unlike most in that they cannot regenerate their tails. Furthermore, there are few differences between the eastern collared lizard and its relative, the western collared lizard. Apart from geographic differences, it is often very difficult to distinguish between the two subspecies (Bartlett and Bartlett 1999).

Contributors

Anisa Ismail (author), Southwestern University, Stephanie Fabritius (editor), Southwestern University.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

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Neotropical

living in the southern part of the New World. In other words, Central and South America.

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desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

native range

the area in which the animal is naturally found, the region in which it is endemic.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

References

Baird, T., D. Timanus. 1998. Social inhibition of territorial behavior in yearling male Collared lizards, Crotophytus collaris.. Animal Behavior, 56: 989-994.

Bartlett, P., R. Bartlett. 1999. A Field Guide to Texas Reptiles and Amphibians. Houston:

Behler, J. 1979. The Audubon Society Field Guide to North American Reptiles and Amphibians. New York:

Bockstanz, L., D. Cannatella. 1998. "Herps of Texas" (On-line). Accessed September 5, 1999 at http://www.zo.utexas.edu/research/txherps/.

Dundee, H., D. Rossman. 1989. The Amphibians and Reptiles of Louisiana. Baton Rouge:

Firth, B. 1980. Independent effects of the pinneal and a baterial pyrogen in behavioral thermoregulation in lizards.. Nature, 285: 399-400.

Sugarman, R. 1988. Feeding evoked by electrical stimulation in collared lizards.. Physiological Behavior, 42: 113-118.