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 19 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 animal’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 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.
The North American porcupine has a head-and-body length that averages about 30 in (76 cm), with an upward-angled tail 9 to 10 in (23-25 cm) long. Body weight is generally less than 26 lb (12 kg), except for particularly large males, which can weigh more than 30 lb (13.5 kg). An adult porcupine possesses about 100 quills per square inch (about per 6 sq cm) from its cheeks, on the top of its head, down its back and onto its tail. There are no quills on its undersides or on the hairless bottom of its feet.
Porcupines are primarily woodland and forest animals of all parts of Canada except the Arctic islands and the United States except the prairie states and Southeast. Nocturnal animals, they readily climb trees, gripping with powerful, curved claws, and may even stay up in the branches for several days at time. They have typical rodent front teeth. These long incisors are orange in color and they grow continuously. Like beavers, porcupines munch bark off trees, although they prefer vegetables and fruits. In spring, however, they go after new buds and leaves. They often swim in order to reach water plants. They are made buoyant by their hollow quills.
One of the few animals that willingly takes on a porcupine is the weasel called a fisher. It teases the animal until it is worn out and easily turned over, where its unquilled underparts can be attacked. Some areas of the country that are being overrun by porcupines have introduced fishers to help eliminate them.
In winter, a porcupine develops a thick, woolly coat under its guard hairs and quills. It will spend much of its time in a den, which is usually a hollow tree, cave, or burrow dug by another animal. It does not hibernate or even sleep more than usual. It goes out regularly in the winter to feed.
Adult porcupines are solitary creatures except when mating, after which the male disappears and is not seen again. After a gestation of 29 to 30 weeks, usually a single well-developed baby, sometimes called a porcupette, is born in an underground burrow. The quills of a newborn are few and soft, but they harden within a few hours. The young stay with the mother for about six months before going off on their own. They become sexually mature at about 18 months and live to be about 10 years old.
The Brazilian thin-spined porcupine (Chaetomys subspinosus ) has quills only on its head. Another species, the prehensile-tailed porcupine (Coendou prehensilis ) has a tail almost as long as its body, which can be wrapped around a tree branch to support the animal.
Old World porcupines of Africa and Asia are often smaller than New World ones and are more apt to have more than one offspring at time. Their tails are structured so that they make a rattling sound when moved, giving warning to an approaching predator.
The brush-tailed porcupines (Atherurus spp. ) have thin tails that end in a brush of white hair. They have more bristles—thick, coarse hair—than quills, which are located only on the back. They climb trees, especially when going after fruit. The long-tailed porcupine (Trichys fasciculata ) of Malaysia lacks the rotund body of most porcupines and looks more like a rat. Its few quills cannot be rattled.
The crested porcupine (Hystrix cristata ) of Africa has quills that may be as much as 12 in (30 cm) long. The hair on its head and shoulders stands up like a crest, which is so coarse as to look like more quills. Crested porcupines are more versatile in their habitats than most animals. They can live in desert, damp forest, open grasslands, and even rocky terrain. Old World porcupines are regarded as a delicacy by native people and may be hunted for their meat.
Incisors— The front cutting teeth of a mammal. In rodents, they grow continuously.
Prehensile— Capable of grasping.
Green, Carl R., and Sanford, William R. The Porcupine. Wildlife Habits and Habitat series. Mankato, MN: Crestwood House, 1985.
Roze, U. The North American Porcupine. Washington, DC: Smithsonian Institution Press, 1989.
Wilson, D.E., and D. Reeder. Mammal Species of the World. 3rd ed. Baltimore: Johns Hopkins University Press, 2005.
Jean F. Blashfield