Get a grip

Science World, Sept 3, 2007 by Cody Crane

Some tree frogs can stick sideways to tree trunks and even hang upside down. Jon Barnes, a scientist at the University of Glasgow in Scotland, recently discovered what gives these frogs their ability to cling at such extreme angles.

Tree frogs rely on a thin coating of sticky mucus on their toe pads to help them adhere. But on the steepest inclines, the frogs' toes can begin to peel away from the surface. Barnes found that to avoid coming unstuck, the frogs spread their legs wide apart. This keeps their feet planted firmly against the surface.

The more contact there is between the frogs' toes and the object underneath, the more friction exists between the two surfaces. This force of resistance helps the frogs stay put.