STICKY FINGERS

It's summertime and the sound of tree frogs chirping at night is deafening at my parents' house. But we love these little guys anyway. They’re so cute and green and hang up side down in the craziest places. But have you ever wondered how they do that? I always imagined that the frogs had little suction cups attached to their fingers, but apparently that’s not right. Tree frogs always secrete mucus from their toe pads and it has always been believed that it is this mucus that allows the frogs to cling to things like ceilings. Well, that’s not true either. Walter Federle and colleagues can demonstrate that a frog's toe pads are in direct and dry contact with what ever surface it might be standing on. Tree frogs squeeze the mucus out through little channels that run in a hexagonal pattern on the toe pads.

It’s obvious the frogs use the mucus for something, just not as glue. It could be possible that the frogs use a similar sticking method as geckos. Geckos use microscopic hairlike structures called seta which in themselves contain a bunch of even smaller hairlike structures called spatulae. All of these tiny hairlike things create so much friction on surfaces that this allows the geckos to stick.

Human engineers are especially interested in figuring out how these creatures can stick so well. One useful application would be in creating tires that have better traction and can grip the road. Then there are the obvious and more fun uses for this technology. Eventually, every kid will be able to buy gecko gloves and socks that will allow them to literally climb the walls.