Rodents

the order of gnawing animals. It includes the tree squirrels, chipmunks, ground squirrels, flying squirrels, prairie dogs, woodchucks, beavers, mice, rats, muskrats, lemmings, moles, jumping mice, pocket gophers, porcupines, hares, and rabbits. There are in all about 371 species of rodents. Of these, about 170 are found in North America. A rodent may be known by its front teeth. They have the shape of chisels and are designed to cut vegetable substances, gnaw shells of nuts, etc. The front portion of the tooth, or cutting edge, consists of the hardest enamel; the rear is softer and wears away more rapidly, leaving the front edge keen and sharp. The tooth grows as fast as it wears off. Many animals that resemble the rodents in appearance belong to other orders. The bats, for instance, look like mice; but they are not rodents. They have sharp teeth, instead, suited for eating insects and fruit. Moles and shrews also have sharp teeth. They are insect eaters, not rodents. A similar remark applies to the hedgehog of Europe. A systematic notion of American rodents may be had from the special articles on SQUIRRELS; CHIPMUNK; GROUND SQUIRREL; BEAVER; MOUSE; RAT; POCKET GOPHER; PORCUPINE; HARE; RABBIT. See also PRAIRIE DOG; WOODCHUCK; FLYING SQUIRREL.