Green Anole

Green Anole The Carolina, or green, anole (Anolis carolinensis) is one of the most frequently seen reptiles in Alabama. The species is common throughout the Southeast and is the only native lizard capable of changing color. Although this has led many people to refer to it as a chameleon, it is unrelated to true chameleons (Chamaeleonidae), which are Old World lizards. Anoles belong to the Iguanidae, a family of arboreal New World lizards that also includes iguanas and chuckwallas.

The green anole is slender, with an elongated pointed head and a tail that accounts for 60 to 70 percent of its body length. It possesses adhesive footpads that allow it to climb smooth surfaces. Males average 5-8 inches (15.2~17.8 centimeters) and have a distinctive pink or reddish dewlap, or throat-pouch, under the lower jaw. Females average just under 5 inches (12.7 cm). These anoles can change their overall coloration from green to brown to grey, and this is not just a matter of camouflage but depends on mood, temperature, and humidity as well as surroundings. Anoles take on a green color during periods of activity and when they are in bright ambient light, whereas they take on their brown coloration during periods of reduced activity and in moist, dark, and cool conditions. The color change is produced by three layers of pigment cells (chromatophores) in the anole's skin. Differing combinations of yellow (xanthophores), blue (cyanophores) and brown-black cells (melanophores) change the animal's overall pigmentation.

Green anoles are common around homes, in yards and gardens, on rocky walls, in low bushes and shrubs, and in woodlands. They require green vegetation and moisture. In urban and suburban areas, they can be seen on fences and rooftops. In cool weather, anoles can be found under tree bark or shingles or in rotting logs. Multiple anoles will sometimes shelter together. In warm weather, they bask in patches of exposed sunlight, from which they dash or lunge to court mates, challenge rivals, and seize prey. Unlike reptiles that track their prey by scent through tongue-flicking or heat sensing, like many species of snake, anoles are sight hunters and must see their prey move in order to find it. They eat small insects, grubs, and spiders.

Anoles breed from late March to early October. The male engages in a courtship display by spreading his dewlap and bobbing at the female. If she is not ready to mate, she will run away. If she consents to mating, she lowers her head to allow him to grasp her neck in his mouth prior to mounting her. After mating, she will lay a single small leathery egg every two weeks for a total of ten eggs per breeding season. Males protect their territory with dominance displays, bobbing at other males in a push-up like movement, flaring their dewlaps, and then turning to the side and arching their backs to enlarge their profiles. This contest continues until one male assumes a submissive posture, bobs his head, and retreats.

The brown phase of the green anole should not be mistaken for the brown anole (Norops sagrei), an invasive species from the Caribbean recently reported in extreme southern Alabama. Brown anoles are generally a darker uniform brown and do not display the faint markings seen on the backs of green anoles in their brown phase.

The scientific community considers the green anole particularly important for study. It has been used as a model organism for observing neurological disorders and for testing drug-delivery systems and biochemical pathways related to human illnesses. The genus Anolis, which includes more than 350 recognized species, has been of major interest in exploring evolutionary diversification, as well. In 2005, the scientific community chose the green anole as its first target species for reptilian genome sequencing.

The International Union for Conservation of Nature (IUCN) lists the green anole as being of lowest conservation concern, meaning it is considered neither endangered nor threatened. There is evidence of declining populations in the southeastern United States, however, likely the result of a combination of habitat destruction and the introduction of the invasive brown anole, which occupies the same ecological niche and which preys on juvenile green anoles.

Further Reading

  • Conant, Roger, and Joseph Collins. A Field Guide to Reptiles and Amphibians, Eastern and Central North America. New York: Houghton Mifflin, 1998.
  • Guyer, Craig, Mark A. Bailey, and Robert H. Mount. Lizards and Snakes of Alabama. Tuscaloosa: University of Alabama Press, 2019.

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