Mice, rats, hamsters, guinea pigs, squirrels and woodchucks flourish among the approximate 1,500 species of rodents. Rodents inhabit all continents except Antarctica. Rodents commonly inhabit urban and rural areas and forests.
Squirrels populate most of the planet. More than 200 squirrel species range in size from the 5-inch African pygmy to the 36-inch Indian giant squirrel. Squirrel species also include ground squirrels, tree squirrels and flying squirrels.
Some people keep familiar rodents as pets, such as guinea pigs, hamsters, mice and rats, but most rodents live in underground dens or tree nests. Less frequently observed, porcupines and lemmings live in the wild.