The lizard that hangs from glass by one toe and licks its own eyes
This lizard can hang from a sheet of glass by a single toe — and lick its own eyeballs clean.
Which one is REALLY true about the Gecko?
The short version
A gecko's toes are covered in millions of microscopic hairs (setae) that tap into molecular van der Waals forces, letting it cling to smooth glass or a ceiling — and theoretically hold many times its body weight. Many geckos have no eyelids and lick their eyes clean with their tongue.
Why it's so weird
- ✓The Gecko can hang from a pane of smooth glass by just a single toe.
- ✓The Gecko has toes covered in millions of microscopic hairs called setae.
- ✓The Gecko sticks using faint molecular forces between surfaces, not suction and not glue.
- ✓The Gecko could theoretically hold many times its own body weight with its grip.
- ✓The Gecko often has no eyelids at all, so it licks its eyes clean with its tongue.
You could line up about 8 of them along a 7-year-old!
The full story
This lizard can hang from a pane of glass by just a single toe. Meet the gecko, a small reptile with one of the most incredible grips in all of nature. Its secret is not suction and it is not glue. Each toe is covered in millions of microscopic hairs called setae, so tiny that they tap into the faint molecular forces between surfaces. That lets a gecko stick to almost anything, even upside down on smooth glass or a polished ceiling. Together, those hairs could theoretically hold many times the gecko's own body weight. And here is a bonus oddity. Many geckos have no eyelids at all, so they simply cannot blink. Instead, they keep their eyes clean and clear by licking them with a long, flexible tongue. A living, self-cleaning piece of climbing technology. Follow for more weird animal facts.
A gecko's toes are covered in millions of microscopic hairs called setae, and each hair splits into hundreds of even tinier flattened tips. When the gecko presses and gently slides its toe, these tips touch the surface so incredibly closely that a faint natural pull between molecules — the van der Waals force — takes hold. Each single contact is super weak, but billions of them working together add up to a grip strong enough to hold many times the gecko's weight. It isn't glue or suction: the gecko tips its toes to grab and peels them up to let go, which is why it can dangle from smooth glass by one toe.
📚 Source: Evidence for van der Waals adhesion in gecko setae (Autumn et al., 2002, PNAS) ↗In a 2002 study, scientists measured the pull of a single gecko foot-hair and found it stuck equally well to water-repelling and water-loving surfaces, showing the grip comes from molecular van der Waals forces rather than moisture, glue, or suction.
📚 Source: Evidence for van der Waals adhesion in gecko setae (Autumn et al., 2002, PNAS) ↗Watch the 45-second version
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“The Gecko has toes covered in millions of microscopic hairs called setae.”