"The sensations that inspire a crayfish escape are so different from our own that they're hard for us to understand. For instance, it is difficult to say whether crayfish have ears, mostly because the notion of an ear is an entirely anthropocentric one. Unlike human ears, which have fine sensory hairs inside structures called cochlea, crayfish have fine sensory hairs covering their entire bodies. Anyone illuminating a crayfish from behind can see these dense and almost perfectly transparent hairs wafting from every inch of the hard exoskeleton. Short hairs detect vibrations in the water that are similar to sound waves, while longer hairs record the changes in slower-moving currents of water such as the pressure wave that radiates from the leading edge of a predator's attack."