Anolis carolinensis or green anole (US: /əˈnoʊ.li/ ⓘ) (among other names below) is a tree-dwelling species of anole lizard native to the southeastern United States and introduced to islands in the Pacific and Caribbean. A small to medium-sized lizard, the green anole is a trunk-crown ecomorph and can change its color to several shades from brown to green.
Other names include the Carolina anole, Carolina green anole, American anole, American green anole, North American green anole and red-throated anole. It is commonly called chameleon in the southeastern United States and sometimes referred to as the American chameleon (typically in the pet trade) due to its color-changing ability; however, it is not a true chameleon.
Anolis carolinensis is a species of the large lizard genus Anolis within the family Dactyloidae (anole lizards). This species was named by Friedrich Siegmund Voigt (1781-1850) in 1832.
Phylogenetic evidence indicates that the Carolina anole belongs to the Anolis carolinensis anole series, a wider clade of Caribbean Anolis which are all also known as "green anoles". This group is composed of mid-sized trunk-crown anoles with large, conspicuously elongated heads and extreme levels of sexual dimorphism. Other members of this thirteen-species clade include A. brunneus & A. smaragdinus from the Bahamas, A. longiceps from Navassa Island, A. maynardii from the Cayman Islands, and A. allisoni & A. porcatus from Cuba; A. carolinensis is the only member of this clade native to the American mainland. Genetic analysis indicates that A. carolinensis originates from an oceanic dispersal event of an ancestral green anole from Cuba to the southern United States during the late Miocene or Pliocene. This is a rare example of an insular species successfully colonizing the mainland of a continent rather than the more common vice versa, although several other Caribbean animal and plant groups have similarly successfully colonized mainland North America via Florida. The present diversity of Central and South American anoles is also thought to originate from a colonization of the American mainland by an insular Caribbean anole taxon.