Rodents are the largest order of mammals; the 4,000 species make up nearly half the world's mammal species. Extremely wide spread, rodents are found in nearly every habitat on Earth from the Arctic to the desert. Rodents have large front teeth for gnawing, cheek teeth for chewing and handlike front paws. Hares and rabbits were once considered rodents. However, they are now classified in their own order, lagomorpha.
Mice are small rodents with brown or grey fur, hairless tails and large ears. At least 1,100 species exist, including field mice, house mice, harvest mice, pack rats and rice rats. One of the most familiar types of mice, house mice are about 6 inches long and weigh less than an ounce. Mice living in homes contaminate food, chew up clothing and paper for nests and often carry a variety of diseases, such as typhoid and spotted fever.
The classification of rat refers to a variety of aggressive, omnivorous rodents with stout bodies, pointed muzzles, nimble paws and long, naked tails. Hundreds of species are included in the genus "rattus," but brown rats and black rats are considered the most familiar.
Black rats are about 8 inches long and have dark grey fur, long tails and large ears. Black rats often are found in upstairs rooms and attics. They like the warm climates of the southeastern United States, the Mediterranean and Latin America.
Brown rats grow up to 10 inches long and weigh up to a pound. Brown rats have brown and white fur and pink ears, tails and feet. They are good at swimming and burrowing. Brown rats often are found in damp environments in large cities. The white rats in science labs are albino brown rats.
Squirrels are found throughout the world except Australia. Commonly seen in city parks and woods, the familiar tree squirrel must come down from the trees in search of nuts, acorns, flowers and berries. They also enjoy tree sap, bark, eggs and baby birds.
Ground squirrels live in tunnels and burrows. They eat plants, seeds, nuts and roots, but also catch insects and larvae. Ground squirrels have few defences against predators other than running away. However, large groups sometimes warn one another of danger by whistling.
Flying squirrels live in nests and holes in the boughs of trees like birds. However, they can't actually fly. They glide with parachutelike flaps between their legs. They feast on nuts, fruit, baby birds and insects.
More than 4 feet long, 1.6 feet tall and weighing more than 45.4 Kilogram, capybaras are the largest rodents in the world. They have barrel-shaped bodies, short heads and reddish-brown to yellowish-brown fur. Capybaras are semiaquatic herbivores that feed on water plants and grasses. The social animals live in groups led by dominant males. Native to South America, capybaras are found in Panama, Colombia, Peru, the Guyanas, Brazil, Paraguay, Argentina, Uruguay and Venezuela.
Chinchillas are natives of the Andes Mountains. The rodents are slightly larger than guinea pigs. They range in size from 482 to 794gr, females are larger than the males. Extremely long-lived for rodents, some chinchillas have lived to 20 years old. They have soft grey fur that became popular in the fur trade in the 19th century. Once so abundant that explorers sometimes saw several hundred in a day, by the early 1900s both species of chinchilla were hunted to near extinction. However, in 1910, the Andean countries signed an agreement banning the capture and trade of chinchillas. Chinchillas are now raised in captivity. Domesticated pelts are considered superior to wild pelts.