There, safe from prowling animals on the ground below, he hangs like a hammock from the bough. The long fingers of his hand (in some sloths two, in others three, in number) and the three toes of his twisted hind feet, all armed with long claws, seize the branch like grappling irons; while his long flexible neck, which in one kind of sloth has more joints than in other mammalia, enables him to look over his shoulder and take a wide survey around. In the daytime he sleeps with his back in the fork of a branch and his head bent forward on his chest, but as the sun goes down he rouses to life and feeds by stretching out those long arms to tear the leaves and twigs, which he stuffs into his mouth and chews with his few back teeth. He has no need to hurry or disturb himself, for his long thick hair protects him from insects; and from the very fact of his being fitted for a tree-life he is safe from other animals except snakes, and even they do not find him out easily, so like is his dull matted hair to the colour of the bark and moss. Even the young ones run very few risks, for they are not born till they are perfect, and then the baby sloth clings to its mother’s hair, and goes with her wherever she travels, sucking till it is old enough to hang on to a bough and feed itself. So they live a completely tree-life, and sleepy as they seem, yet they can move quickly enough when they wish; and they often take advantage of a time when the wind is blowing so that the branches from tree to tree sway against each other, and by seizing the boughs as they touch, pass along and find new feeding-grounds.