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threatened and/or endangered

Common Porcupine Erethizon dorsatum


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Common Porcupine
credit: J. Glover/CCSA

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Family: Erethizontidae, New World Porcupines view all from this family

Description The only mammal in North America with quills. Males are larger, but females have longer tails. Slow and with poor eyesight, this large rodent is well protected from predators by its quill armor.

Dimensions 60-130cm, 17-25cm, 3.5-18kg

Warning A Porcupine may lash out with its spiny tail if approached too closely. Quills can become painfully embedded in the victim's skin. Cutting the end off the quill releases air pressure and allows it to be more easily withdrawn.

Breeding Breeding may occur in almost any month, depending on location. The long gestation period is 204-215 days, and the single young weighs 400-500g at birth.

Habitat Scrub, shrub & brushlands, Forests & woodlands

Range Plains, Great Lakes, New England, Mid-Atlantic, Rocky Mountains, Southwest, California, Northwest, Eastern Canada, Western Canada, Alaska

Discussion Defends itself by erecting (not throwing) its quills, lowering its head, and backing up toward the intruder with its tail flailing. Dens in burrows, rocky crevices, and hollow trees. Eats a variety of plant material, but is especially fond of the cambium layer of coniferous trees, with hemlocks being a particular favorite. Will strip bark off trees and leave piles of feces beneath. Evidence of their feeding includes girdled trunks and branches contrasting markedly with uneaten parts of the trees. They also feed on a variety of smaller shrubs and canes. In spring, when new growth is available, porcupines feed more on the ground using succulent stems of wildflowers, sedges, and grasses. In summer they sometimes move into agricultural fields to feed on ripening crops, especially corn. In winter, when other food is scarce, they add acorns to their diet. Maximum lifespan is 10 years. Porcupines are solitary, although communal dens are known in the wintertime. Extirpated from many areas in the eastern and Midwestern United States. Recently reintroduced in some areas. Rare to common in a variety of habitat types including forest, tundra, chaparral, and rangelands, from sea level to high mountains in the west.