Many kinds of geckos have perfected the art of cleaning their corneas with their tongues.
Question: It’s so cool the way lizards can lick their eyeballs with their tongues. I’ve seen my tokay gecko do it twice, but can never get a photo of it because it always happens too fast. They do it to clean their eyes, right?
Dillon Jensen, Carson City, Nev.
This South American turnip-tailed gecko (Thecadactylus rapicauda) is washing its eye in response to the author’s camera’s flash annoying it.
Answer: Many kinds of geckos have perfected the art of cleaning their corneas with their tongues. These visually oriented predators, many of which hunt at night, depend on unobscured vision to find food and avoid predation. Keeping their large eyes glistening clean is part of the reason for their success worldwide.
Your comment about finding it hard to photograph this behavior caught my eye because of a small trick I learned decades ago. Using a strobe flash, as I frequently do, often elicits such a tongue bath. The flash must serve as a slight irritant to the geckos, and they typically respond afterward with a lot of eyeball licking at regular intervals for the next five to 10 seconds, making photographing the action a much easier task.