Today's creature feature is the amazing gecko. Many species of geckos are expert tree climbers. But geckos have no suction cups or sticky goo to explain their amazing climbing and clinging abilities. So what sends geckos up a wall? The answer can be found under the microscope.
Gecko feet have hundreds of thousands of tiny bristles called setae -- each one 10 times thinner than a single human hair. And each of these setae, in turn, has hundreds of pillar-like projections that end in spatula-shaped structures. At the nanoscale, the molecules in these "spatulas" are attracted to the molecules of the surface the gecko is climbing.
In the 1800s, Dutch physicist Johannes Diderik van der Waals first described this weak attraction (or repulsion) between molecules of different surfaces. The attraction is weak, but with thousands of bristles to work with, it quickly adds up. Geckos can "stick with it" while climbing trees or navigating boulders to find food or escape danger. Geckos have gained or lost this trait numerous times over their evolutionary history in response to changing habitats.
Now, get going with a gecko-inspired experiment at home. Take two unneeded phone books or catalogs and interleave the pages together: prop up the spines and overlap the pages in the middle, alternating one page at a time from each book. There is a weak attraction between the pages themselves, and it adds up over hundreds of pages. Try pulling them apart!
Like the pages in your books, the weak attraction of microscopic gecko hairs adds up. Inspired by geckos, engineers have designed better stick-and-peel surgical tapes, and mechanical gecko robots that can scale glass walls. Future "mecho geckos" may even traverse the rocky red terrain of Mars. Gecko-inspired designs are just one example of biomimetics -- technology that mimics nature. With geckos, saving hundreds on car insurance was only the beginning.