The primary factor that keeps species of anole lizard from mating with one another is that different species living in the same habitat have different.
The dewlap is a flap of loose skin that hangs beneath the neck of many vertebrates. Dewlaps are found in mammals, birds and reptiles. In the case of the anole lizard, dewlaps have particular significance because the lizards are able to spot one another's dewlaps from a distance. Dewlaps also help the lizard appear larger than it actually is.