AMONG THE MANY reasons humans are bizarre among mammals (the dearth of body hair, the bipedalism, the fact that someone invented the turducken) is a sad shortcoming: You and I don’t have sensory whiskers. Cats, dogs, raccoons, sea lions—you name a mammal and it’s probably got special hairs sprouting out of its face. After all, whiskers are immensely useful. Rats use them to navigate the darkness, for instance, while a seal’s whiskers detect the movements of fishy prey.