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American Porcupines, Old World Porcupines

Two families of rodents are called porcupines. They all have at least some hair modified into quills. The Old World porcupines belong to family Hystricidae of Europe, Asia, and Africa. The New World porcupines are 10 species of forest dwellers of the family Erethizontidae. The most common of these is the North American porcupine (Erthizon dorsatum). The name porcupine means "quill pig," though these rodents are not pigs.

Porcupines have one of the most unusual kinds of fur in the animal kingdom. Hidden beneath its shaggy brown, yellowish, or black coat of guard hairs is a mass of long sharp quills. Quills are actually specialized hairs, solid toward the skin and hollow toward the dark end. They lie flat when the animal is relaxed and rise alarmingly if the animal is startled. When the animal tenses its muscles the quills rise out of the guard hairs, providing a protective shield that keeps enemies away.

They do give warning, however. Either the quills themselves make a rattling sound when shaken or the an imal's tail makes a warning sound. The animal also stamps its feet and hisses. If the warnings go unheeded, the animal turns its back and moves quickly backward or A porcupine (Hystrix africaeaustralis) with its quills erect. © Mark N. Boulton/The National Audubon Society Collection/Photo Researchers, Inc. Reproduced by permission. sideways toward the approaching predator, giving it little time to realize its own danger.

Myth holds that a porcupine can actively shoot its quills into a predator. This is not true. However, if an enemy attacks, the quills stick into its flesh and are easily pulled out of the porcupine's skin. Quills have small barbs on the end that prevent the quill from being pulled out. Instead, they have to be carefully removed, rather like a fishhook. In the wild, quills gradually work their way into the predator's body, harming organs, or into the throat, preventing the animal from eating until it starves to death. The porcupine grows new quills to replace the lost ones within a few weeks.

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