Van der Waals forces in action

Geckos have millions of setae--microscopic hairs on the bottom of their feet. These tiny setae are only as long as two diameters of a human hair. Each seta ends with 1,000 even tinier pads at the tip. These tips, called spatulae, are only 200 nanometers wide--below the wavelength of visible light. These spatuale increase surface density phenomenally, creating a strong adhesive force through van der Waals interactions. Geckos stick to hydrophilic and hydrophobic surfaces equally well. If a gecko used all of its setae at the same time, it could support over 100 kilograms. 

Many small animals (e.g. insects and spiders) partially exploit van der Waals forces.