Head to head
Brown Anole vs Green Anole
In the southeastern United States there are now two small anole lizards where there used to be one. The green anole is the native, the only anole in the region for most of its history. The brown anole is an invader from Cuba and the Bahamas that arrived in Florida over a century ago and spread explosively from the 1970s. Where they meet, they do not simply share the space; the brown anole takes the ground floor and the green anole moves upstairs.
| Brown Anole | Green Anole | |
|---|---|---|
| Status in the US | Invasive, from Cuba and the Bahamas | Native to the southeastern US |
| Can it turn green? | Never; always brown or grey | Yes, shifts between green and brown |
| Throat fan | Orange-red with a yellow border | Pink |
| Back pattern | Diamonds, triangles, or a scalloped stripe | Plain, unmarked |
| Where it perches | Low: ground, trunks, fences | Higher: shrubs and canopy (since the invasion) |
| Breeding | One egg every week or two, all season | Similar, but pushed to worse sites where brown anoles dominate |
| Density | Very high, over one per square metre | Lower where brown anoles are dense |
| Interaction | Eats green anole hatchlings; displaces adults upward | Retreats up; has evolved bigger toe pads in response |
Brown Anole vs Green Anole: common questions
How do I tell a brown anole from a green anole?
Colour is the first clue but it can mislead, because a green anole is often brown. The rule that works: a green lizard is always a green anole, but a brown lizard could be either. So check other features. A brown anole has a patterned back, often with light diamonds or a scalloped stripe, and a bright orange-red dewlap with a yellow edge, and it sits low, near the ground. A green anole, even when brown, has a plain unmarked back, a pink dewlap, and is now usually up in the shrubbery or a tree. Brown anoles also tend to hold their tails curled and to be far more numerous in any given yard.
Did the brown anole really make the green anole evolve?
The evidence is unusually clear. Researchers introduced brown anoles to some small islands in a Florida lake and left others alone, then tracked the resident green anoles. On the islands that got brown anoles, green anoles moved to higher perches within months, and after about fifteen years, roughly twenty generations, those populations had evolved larger toe pads with more of the microscopic clinging hairs, better suited to the narrow, smooth branches of the upper canopy. Green anoles on the brown-anole-free islands did not change. It is one of the best field demonstrations that natural selection can reshape a wild animal within a human lifetime.
Are green anoles disappearing because of brown anoles?
Not disappearing, but changing where they live and, in many yards, becoming much harder to spot. Where brown anoles are abundant, green anoles are seen far less often at ground and fence level and are largely confined to the shrub and tree canopy, so casual observers assume they have gone. Studies that look up into the vegetation still find them, coexisting with the brown anoles by partitioning the habitat. The green anole is not considered threatened, but the invasion has genuinely squeezed it into a smaller slice of its former niche, and in some heavily built-up areas with few tall plants it may be locally scarce.