Gecko Facts

About the gecko

With nearly 2,000 species, geckos make up the most species-rich lizard group, and they turn up on every continent but Antarctica, always in warm climates. Sizes swing wildly, from 1.6 to 67 centimeters (0.6 to 26.4 inches) long. Many species chirp or click when socializing, the tokay gecko gives loud mating calls, and some others hiss when alarmed.

Most geckos have no eyelids. A clear membrane called the brille covers each eye instead, so these lizards lick their eyes to wipe off dust and keep them moist. Only the family Eublepharidae has lids. Most species hunt at night, and their color vision in dim light is 350 times more sensitive than a person's. Their eyes can also form a sharp image at two or more depths, and a fixed lens in each iris widens in the dark to gather extra light.

Did you know?

• Every gecko belongs to the lizard suborder Gekkota, a group found in warm places worldwide.
• Nocturnal geckos descended from daytime species that had lost the rod cells in their eyes.
• Gecko eyes keep three light-sensing pigments, tuned to ultraviolet, blue and green.