Since ancient times, readers have recognized that the dogs, foxes, lions, ants, grasshoppers, and other creatures in Aesop’s fables represent features or types of human nature. Still, particular species were chosen by Aesop with evident care (hence, an industrious ant is paired with a heedless grasshopper), so Aesop was working with some ideas about animal nature too. Using the fables as a framework, Jo Wimpenny explains the science of animal nature, which turns out to be is as diverse and interesting as human nature itself. Dan Falk reviews her book, Aesop’s Animals.