At the beginning of this video, the anole lizard we’re watching is deep brown. By the end, he’s green – and not a dull, brownish green, either; he’s a vivid, put-your-sunglasses-on, bright spring green.
How do these lizards manage to perform such a magical trick? Well, while we apparently understand the process quite well at the cellular level (and you can listen to Dan’s narration to learn about chromatophores and hormones and skin layers), we’re not entirely sure about what’s happening at the lizard level.
What makes an anole “want” to turn from green to brown or vice versa?
Here are a couple of things that apparently don’t have an impact on the color of green anoles*:
– They don’t change color in order to match their environments and blend in. We often spot them here hanging out on a branch, bright green and sticking out like little sore thumbs.
– It doesn’t seem to have anything to do with air temperature; it had been postulated that color changes had something to do with thermoregulation but apparently that’s been debunked.
However, it has been observed that adult males spend more time being green than females or juveniles, so perhaps some kind of sexual signalling is involved? Maybe being green, in the green anole world, is like driving around in a red Porche?
Another observation is that the adults males change color frequently during male-male encounters, and if there’s some competition involved, the winner will usually wind up green and the loser will be brown.
Here’s an interesting article from Anole Annals about color changing in green anoles: https://www.anoleannals.org/2012/02/24/new-study-on-color-change-in-green-anoles. Our thanks to the author, Jonathan Losos, for educating us about these fascinating creatures.
* Even though the lizard we see in this video is brown about half of the time, species-wise, it’s a green anole lizard. And yes, that is a little confusing.
** Here in Texas, the common pronunciation of the name of these lizards is 2 syllables, “a-nole”. Many people, however, know them as “a-nole-y” lizards. Three syllables.