Geckos Cannot "Stick" to Wet Surfaces

Geckos are being studied to find out how they can climb across ceilings without falling off. Their toe pads can support weight equivalent to two people.

Like many animals with the capacity to "stick" to things, the main reason they can hold on is the many tiny hairs on their suckers. A hair is further divided into hundreds of gripping setae. The attraction between molecules in the surface and the millions of setae add up to significant sticking power.

Water is their enemy. If a surface is wet they fall off. Even on a dry surface, when gecko's feet are soaked in water they cannot hold on. Water tends to stop the superhydrophobic attracted between molecules. This is why geckos lose their wonderful climbing ability. In the wild they would be open to attack from predators in wet conditions. Furthermore, the hope of creating a new adhesive based on geckos is dashed.
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