Why do geckos stick to walls and ceilings?

Gecko toe pads are covered with millions of tiny hair-like structures called setae, which split into even smaller spatula-shaped tips. These tiny tips get so close to surfaces that weak molecular attractions, called van der Waals forces, become strong enough to support the animal's weight. This works on many dry, smooth surfaces and can be released simply by changing the angle of the toes. Scientists have studied gecko adhesion extensively because it inspires climbing robots and reusable adhesives. It is one of the best-known examples of biomimicry in modern science.