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The Old World porcupines, or Hystricidae, are large terrestrial rodents, distinguished by the spiny covering from which they take their name. They range over the south of Europe and the Levant,〔http://biblehub.com/topical/p/porcupine.htm〕 most of Africa, India, and the maritime Southeast Asia as far east as Flores. Although both the Old World and New World porcupine families belong to the Hystricognathi branch of the vast order Rodentia, they are quite different and are not closely related. == Characteristics == Old World porcupines are stout, heavily built animals, with blunt, rounded heads, fleshy, mobile snouts, and coats of thick cylindrical or flattened spines, which form the whole covering of their bodies, and are not intermingled with ordinary hairs. The habits of most species are strictly terrestrial. They vary in size from the relatively small long–tailed porcupine with body lengths of , and a weight of ,〔ADW Animal Diversity Web〕 to the much larger crested porcupines, which are long, discounting the tail, and weigh from . The various species are typically herbivorous, eating fruit, roots, and bulbs. Some species also gnaw on dry bones, perhaps as a source of calcium. Like other rodents, they have powerful gnawing incisors, and no canine teeth. Their dental formula is One or two (or, rarely, three) young are born after a gestation period between 90 and 112 days, depending on the species. Females typically give birth only once a year, in a grass-lined underground chamber within a burrow system. The young are born more or less fully developed, and the spines, which are initially soft, harden within a few hours of birth. Although they begin to take solid food within two weeks, they are not fully weaned until 13 to 19 weeks after birth. The young remain with the colony until they reach sexual maturity at around two years of age, and share the burrow system with their parents and siblings from other litters. Males, in particular, help defend the colony from intruders, although both sexes are aggressive towards unrelated porcupines.〔 These rodents are also characterized by the imperfectly rooted cheek-teeth, imperfect clavicles or collar-bones, cleft upper lip, rudimentary first front-toes, smooth soles, six teats arranged on the side of the body, and many cranial characters. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Old World porcupine」の詳細全文を読む スポンサード リンク
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