|Male brown anole displaying dewlap|
Duméril and Bibron, 1837
The brown anole (Anolis sagrei) is a lizard native to Cuba and the Bahamas. It has been widely introduced elsewhere, by being sold as a pet lizard, and is now found in Florida and as far north as southern Georgia, Texas, Taiwan, Hawaii, Southern California, and other Caribbean islands.
This species is highly invasive. In its introduced range, it reaches exceptionally high population densities, is capable of expanding its range very quickly, and both outcompetes and consumes many species of native lizards. The brown anole's introduction into the United States in the early 1970s has altered the behavior and triggered a negative effect on populations of the native Carolina anole (Anolis carolinensis, also known as the green anole), which have generally been relegated to the treetops.
Brown anoles are normally a light brown color with markings on their back that are a darker brown to black, and on their sides they have several tan to light color lines. Like other anoles, they can change color, in this case a darker brown to black coloration. They also have a dewlap that ranges from yellow to orange-red. The males can grow as large as their green anole male counterparts, slightly smaller or bigger depending on the individual: around 17.8–20.3 centimeters (7–8 inches), with some individuals topping 22.9 centimeters (9 inches). The females are also around the size of the female green anole: 7.6–15.2 centimeters (3–6 inches). The male brown anole's head is smaller than that of the male green anole. Also the brown anole's tail has a ridge that travels all the way up to behind the head, a feature the green anole lacks.
Brown anoles molt in small pieces, unlike some other reptiles, which molt in one large piece. Anoles may consume the molted skin to replenish supplies of calcium. In captivity, the molted skin may stick to the anole if humidity is too low. The unshed layer of skin can build up around the eyes, preventing the lizard from feeding and leading to starvation. This can be prevented by maintaining high humidity.
The brown anole feeds on insects such as crickets, grasshoppers, cockroaches, mealworms, and waxworms as well as other arthropods including spiders. They may also eat other lizards, such as the green anole, lizard eggs, and their own molted skin and detached tails. If near water, it will eat aquatic arthropods or small fish – nearly anything that will fit in its mouth.
As a defense mechanism, brown anoles can detach most of their tails when pursued or captured. The piece that breaks off will continue to move, hopefully distracting the predator and allowing the anole to escape. The lost tail will partially regrow. If provoked, the brown anole will bite, urinate, and defecate. Predators include rats, snakes, birds and many larger predators.
Recent work in experimentally introduced populations in the Bahamas has shown that body size in the brown anole may not be affected by predation, as was previously thought.
- Gary Nafis (2000–2013). "Non-Native Reptiles and Amphibians Established In California". CaliforniaHerps.com. Retrieved 2013-02-01.
- Kolbe, J.J., R.E. Glor, L.R. Schettino, A.C. Lara, A. Larson and J.B. Losos 2004. 'Genetic variation increases during biological invasion by a Cuban lizard Nature 431:177-181
- Losos, J.B., J.C. Marks and T. W. Schoener. (1993). Habitat use and ecological interactions of an introduced and a native species of Anolis lizard on Grand Cayman, with a review of the outcomes of anole introductions. Oecologia 95:525-532
- Campbell, T.S. 2000. Analysis of the effects of an exotic lizard (Anolis sagrei) on a native lizard (Anolis carolinensis) in Florida, using islands as experimental units. PhD Thesis, Univ. of Tennessee
- Gerber, G.P. and Echternacht, A.C. 2000. Evidence for asymmetrical intraguild predation between native and introduced Anolis lizards. Oecologia 124: 599-607.
- R.D. and Patti Bartlett (1999-2013). "Choosing a Brown Anole". PetPlace dot com. Retrieved 2013-1-16.
- Casanova, L. 2004. "Norops sagrei" (On-line),Animal Diversity Web. Accessed July 31, 2008
- Calsbeek, R., and R.M. Cox. (2010). Experimentally assessing the relative importance of predation and competition as agents of selection. Nature 465:613-616.