A recent study led by Biologist Jon Barnes of the University of Glasgow in Scotland contrasted the differences in how geckos and tree frogs were able to scale surfaces so easily.  It provides some detailed answers to the classic question, “how do tree frogs climb like that?”

They concluded that why the gecko uses a dry grip that creates a molecular bond between its toe pads and the surface being climbed, a tree frog uses nanopillars, which creates a wet grip with the surface being climbed.

Barnes and his team studied the feet of White’s Tree Frogs with an atomic force microscope to better understand how this is being done.

To the naked eye, the frogs’ toe pads appear patterned with flat-topped, hexagonal cells surrounded by grooves filled with mucus. On closer inspection, however, Barnes discovered that the tops were not flat at all but rather were covered by tightly packed “nanopillars,” each with a small dimple in the end, which generate powerful friction against the surfaces they contact.

Tree frogs actually prove more adept at climbing wet, smooth surfaces such as glass or leaves than they do dry, rough surfaces.  The adhesion capabilities in both geckos and tree frogs could influence future improvements to car tires and shoes.

Sticky Business: Tree Frogs Hang Tight–But How? (Scientific American)