Even animals without hands can display handedness--or, at least, a preference to do things with one side of the body rather than the other. Animals ranging from primates to birds to invertebrates have been shown to favor their left or right side. Fish might reveal that preference by choosing to swim right, for example, when avoiding a predator. Don't get too charmed by the idea of left-handed and right-handed fish, though: In a warming world, they may disappear.