Which animal inspired scientists to make a new adhesive that allows people to climb walls?

Geckos are small, mostly carnivorous lizards that have a wide distribution, found on every continent except Antarctica. They range from 1.6 cm (6 in) to 60 cm (23 in). About 60% of gecko species have adhesive toe pads that allow them to adhere to most surfaces without the use of liquids or surface tension.

Scientists have recreated geckolike adhesion using silicones, plastics, carbon nanotubes, and other materials. Mechanical engineer Elliot Hawkes of Stanford tested the new adhesive by strapping his feet to footholds connected to the patches through a rod. He found that he could easily peel off the patches one at a time and stick them to a wall with his hands—which was how the 70-kilogram (154 lb) Ph.D. student ascended a glass wall behind his lab on a crisp December afternoon. At the end of the climb, he even let go of both his hands in a thumbs-up while the patches stuck securely onto the wall, providing him with two secure footholds. He climbed 3.6 meters.

The team is now working with NASA's Jet Propulsion Laboratory (NASA - National Aeronautics and Space Administration) to create adhesive-equipped robots that can catch space junk such as defunct satellites, Hawkes says. In a recent experiment in a zero-g environment, a bot equipped with a small adhesive patch gripped the solar panel of another 400-kilogram (881 lb) robot, slowed it down, and gently pulled it in another direction.