photo of a gecko licking its eyeball
CHRIS MATTISON/NPL/MINDEN PICTURES
Mini Read,

This Lizard Can Lick Its Eyeball!

But don’t say “yuck.” Lizards do this for a reason.

By Talia Cowen
From the September 2020 Issue
Common Core Standards
  • L.3, L.4, L.5, L.6
TEKS Standards
  • Grades 2-3:
    1a, 2a, 3b,3c, 3d, 5a, 7f

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Here’s a challenge: Stick out your tongue and try to lick your nose.

Now stretch your tongue just a little farther and try to lick . . . your eyeball. How far did you get? Only one out of every ten people can reach their nose. Almost no one can reach their eye.

Of course, it’s not actually a good idea for us to lick our eyeballs. But for the crested gecko, it’s a great idea. In fact, it’s extremely important for the small lizard to be able to get its eyeball wet.

That’s because the gecko is missing something that you and I use every day: eyelids.

Amazing Eyelids

SUSAN SCHMITZ/SHUTTERSTOCK.COM

Eyelids are the thin pieces of skin above your eyes. You move them when you close your eyes or blink. Most people blink up to 1,200 times an hour!

Every time you blink, your eyelids wipe away dust and other tiny bits of muck. And if something comes close to your eyes, your trusty eyelids will snap shut to keep them safe. But unlike humans, most geckos don’t have these special pieces of skin to protect and clean their eyes. That’s when a gecko’s long, sticky tongue comes to the rescue!

A gecko will shoot out its tongue to lick its grubby eyeball, coating the eye with a layer of spit (also called saliva). The saliva wipes off all the gunk that has collected there. Now the gecko’s eyeball is squeaky clean! 

FACT FINDER

  • WHAT is an eyelid?
  • WHY do humans blink?
  • HOW do geckos clean their eyes?
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Explore This

Geckos are one type of lizard, but there are more than 4,000 lizard species! Learn all about how geckos and other types of lizards walk, eat, and communicate at this fantastic site from the San Diego Zoo.  

Watch This

The crested gecko isn’t the only gecko that licks its eyes. Take a look at the Namib gecko in action in this 3-minute Smithsonian Channel video!

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