CREATURES as small as fruit flies and as large as geckos stick to walls and ceilings using minuscule sticky pads on their feet called spatulae. Puzzlingly, the bigger the beast, the smaller the pads, and now researchers think they know why.
Spatulae probably work through a weak molecular force called the van der Waals interaction. Because larger animals weigh disproportionately more compared to their surface area than smaller animals, they need more spatulae to stick. So they make them smaller and pack them more densely. Flies have thousands, geckos have millions.
When Eduard Arzt from the Max Planck Institute for…
