The domestic rabbit is not native to the United States. Rabbits and hares inhabit most of the temperate regions of the world. Some old classification systems had them related to the rodents. Like rodents, rabbits possess chisel-like or gnawing teeth that continue to grow if not worn by chewing. Rabbits, however, have two upper and two lower incisor teeth and two smaller pulp teeth behind the upper incisors.
Rabbits have a total of six teeth rather than four, as is characteristic of rodents.
Hares differ from rabbits because they are born fully haired, with their eyes open and are able to run within a few minutes after birth. Their legs are longer than those of rabbits, and they take long leaps when running. Young are born in the open without a nest. In contrast, rabbits' young are born in a fur-lined nest, and are blind, helpless, and hairless at birth. Breeds of modern domestic rabbits have developed since the 18th century.