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Description

The brown anole, Anolis sagrei, is a small brown or gray lizard that is about 5 to 9 inches in total length. Males usually weight twice as much as females (8 grams vs. 4 grams). The coloration in males can even become black. In comparison to the green anole, Anolis sagrei has a shorter head and marking such as yellowish spots, triangles or lines running down dorsal side of the lizard. Females are lighter in coloration and have a dark diamond-back or scalloped pattern running down their backs. When males are defending territory or trying to court a mate they flash their bright red or orange dewlap. When collapsed, the brightly colored skin is hidden and appears as a pale, vertical streak along the neck. Both sexes have a dewlap, but it is smaller and rarely extended in females.

Ecological Threat

Brown anoles are native to Cuba and the Bahamas where they inhabit almost any ecosystem and encounter natural predators that help maintain the brown anole populations. In the United States Anolis sagrei is able to rapidly spread along the southeastern United States due to its diet and habitat adaptability. Brown anoles displace green anoles (Anolis carolensis) from their habitats and compete with the native lizards for food and territory. Both anoles species have been observed to eat the other species’ eggs, but despite this similar trait, brown anoles cause a significant reduction in green anole populations wherever they are present. The displacement and population reduction of green anoles will cause an imbalance in a wide variety of habitats. Anolis sagrei is known to transmit parasites to new environments in Hawaii. With the invasive brown anole living in the same habitat as green anoles they could be transmitting invasive parasites or bacteria that are fatal to the native lizard populations.

Biology

Reproduction occurs during the summer but the establishment of territory beings in the spring. Females lay one egg at a time and they can lay an egg every week. After four weeks, the egg hatches and the hatchlings are independent from the beginning. It only takes Anolis sagrei hatchlings less than one year to become mature adults and they can live up to 5 years in the wild. Brown Anoles eat insects, worms, snails and slugs; in Florida, they have been observed to eat green anole eggs, making them a direct threat to the native lizard species.

History

Anolis sagrei was first documented in the Florida Keys in the 1880s and by the 1940s it was introduced and became established in South Florida. The brown anole has been well established in Georgia for decades and specimens have been collected from Houston since 1987. Expansion of habitat range has been aided by accidental transport via motor vehicles and as accidental introductions (particularly as eggs) with transported live plants has been suggested as the likely source of these introductions.

Native Origin

Cuba, Honduras, the Bahamas and Cayman Islands.

Current Location

U.S. Present: CA, FL, GA, HI, LA and TX

U.S. Habitat: Can be found in any tropical or sub-tropical habitat within range; along forest edges, human-disturbed areas and open sites.

Management

In states where Anolis sagrei is present, no real management strategies have arisen. These lizards will expand their distribution range in the United States because many people consider them ideal as pets and can be bought in local pet stores. Preventing these pet stores from selling the invasive brown anole could help reduce its ability to spread. Since there are established populations all throughout the southeastern United States, prevention and management of the brown anoles needs to occur.

References

Campbell T.S. 1996. Northern range expansion of the brown anole Anolis sagrei in Florida and Georgia. Herp. Review 27:155-157.

Campbell T. 2002. The Brown Anole (Anolis sagrei Dumeril and Bibron 1837). The Institute for Biological Invasions: The Invader of the Month, February 2001.

Goldberg, S. R., & Bursey, C. R. 2009. Transport of helminths to Hawaii via the brown anole, Anolis sagrei (Polychrotidae).

Greene, B. T., D. T. Yorks, J. S. Parmerlee, R. Powell, and R. W. Henderson. 2002. Discovery of Anolis sagrei in Grenada with Comments on Its Potential Impact on Native Anoles. Carribean Journal of Science 38:270-272.

King, K., Cavazos, D., & Judd, F. W. 1987. Anolis sagrei (Sauria: Iguanidae) established in southern Texas. Texas J. Sci, 39:289-290.

Tokarz, R. R., Paterson, A. V., & McMann, S. 2005. Importance of dewlap display in male mating success in free-ranging brown anoles (Anolis sagrei). Journal of Herpetology, 39(1):174-177.

Internet References

http://warnell.forestry.uga.edu/

http://www.sms.si.edu/IRLSpec/Anolis_sagrei.htm (Smithsonian)

http://www.btnep.org/subsites/invasive/