PORCUPINE

also called quill pig, any of the large, quill-bearing rodents of the families Erethizontidae and Hystricidae (order Rodentia). Porcupines are heavyset, relatively short-legged rodents, essentially nocturnal and herbivorous in habit. The New World species (Erethizontidae) are arboreal, and the Old World species (Hystricidae) terrestrial. The North American porcupine (Erethizon dorsatum), best known of the New World species, is a compact, slow-moving animal found in woods from Canada to northern Mexico. It is about 75 centimetres (29 inches) long, with the thick, muscular tail an additional 20 cm or so. The quills, which are modified hairs, are stiff, barbed spines about 7.5 cm long. They are white, tipped with black, and are interspersed among the dark, coarse guard hairs of the back and tail. When approached, the North American porcupine presents its rear to the enemy; if attacked, it drives its powerful tail against the assailant. The quills are easily detached from its skin and remain embedded in the attacker. The animal does not throw its quills, but some may become detached when the porcupine shakes itself. The North American porcupine is a solitary but not antisocial animal. It shows a preference for eating the tender layer of tissue beneath the bark of trees and at times completely girdles, and thus kills, trees. It may also gnaw used ax handles, canoe paddles, and other items for the salt and oil they contain. The porcupine breeds in fall or early winter, and the female bears one or two young, born with soft quills, about seven months later. The family Erethizontidae also includes the prehensile-tailed, or tree, porcupines (Coendou) of forests from Mexico to South America; the short-tailed porcupine (Echinoprocta rufescens) of Colombia; and the thin-spined porcupine (Chaetomys subspinosus) of Brazil. Crested porcupines (Hystrix), the typical Old World porcupines, are distributed through southern Europe, Africa, and Asia. Usually solitary animals, crested porcupines live in burrows and eat roots, fruit, and other vegetation, sometimes damaging cultivated plants. They often breed twice a year, the female bearing one to four young after about two months' gestation. When disturbed, these porcupines turn away from the attacker and rattle their quills. If the threat persists, they run backward, quills erect, and attempt to impale the enemy. The largest terrestrial rodent in Europe and Africa is the African crested porcupine (H. cristata), which attains a total length of about 80 cm and a weight of about 27 kilograms (60 pounds). It has two types of quills: long, flexible, usually white, quills up to 35 cm long; and shorter, stout quills banded with black or brown. The African and certain other crested porcupines have long neck and shoulder quills they can erect to form a crest. There are three other genera of Old World porcupines: the long-tailed and Indonesian porcupines (Trichys and Thecurus) of Asia, and the brush-tailed porcupines (Atherurus) of Africa and Asia.