The Green Anole (Anolis carolinensis) is native to Florida and is the only anole species indigenous to the United States. Often mistakenly called the American chameleon due to its ability to change color, the Green Anole is a small, slender lizard that is an integral part of the state’s natural ecosystem. It is important to distinguish this lizard from other, non-native anole species that have become common, as their presence is the primary source of confusion regarding the Green Anole’s native status.
The Confirmed Native Range
The Green Anole’s native range covers the southeastern United States, extending from southern Virginia west to Texas and south through the Florida Keys. This lizard is well-adapted to Florida’s humid, subtropical climate and can be found in a variety of habitats. As an arboreal species, it spends most of its time above the ground, preferring trees, shrubs, vines, and tall grasses. It is also frequently observed in urban and suburban settings, clinging to fence posts and the sides of buildings.
Florida’s Invasive Anole Population
The confusion surrounding the native status of the Green Anole is largely due to the widespread presence of the Brown Anole (Anolis sagrei), an invasive species. The Brown Anole is native to Cuba and the Bahamas and was first documented in Key West in the late 1800s, likely arriving accidentally as stowaways on cargo ships. Genetic evidence suggests that the species has been introduced to Florida multiple times from various locations in its native Caribbean range. Since its initial introduction, the Brown Anole has spread rapidly, and by the early 2000s, it was documented in every county in peninsular Florida. This highly adaptable lizard thrives in areas modified by humans, such as yards and urban parks.
Key Physical Differences
Distinguishing the native Green Anole from the invasive Brown Anole involves observing several physical characteristics. The Green Anole has a slender body, a long, pointed snout, and can change its color from bright green to brown or gray depending on temperature or mood. Male Green Anoles possess a prominent pink or reddish dewlap—a flap of skin under the throat—used for territorial displays and courtship. In contrast, the Brown Anole has a stockier body, a shorter, blunter head, and is limited to shades of brown, gray, or tan, unable to turn green. The male Brown Anole’s dewlap is a striking orange or yellow-red color, providing a clear visual contrast to the native species’ pink dewlap.
How Competition Affects Native Anoles
The introduction of the Brown Anole has had an ecological impact on the native Green Anole population through competition. Both species have similar diets of small insects and initially occupied similar low-lying habitats, such as the ground, low shrubs, and tree trunks. The more aggressive Brown Anole, which also preys on the eggs and hatchlings of the Green Anole, has outcompeted the native species in these lower perching areas. This pressure has led to niche partitioning, where the Green Anole has been forced to retreat to higher, thinner branches in the tree canopy. Consequently, Green Anoles are now less frequently observed by humans in suburban areas, giving the false impression that their populations have vanished, when in fact, they have simply shifted their habitat use higher up into the vegetation.