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North American Porcupine

Erethizon dorsatum [er uh thI zun dor' sah tum]

North American Porcupine


This large member of the rodent family reaches a length of up to 3 feet (males) and a weight of up to 20 pounds. Its yellowish-brown quills are 2 to 3 inches long, and its fur is brownish-black. Although it cannot "shoot" its quills as some commonly believe, the porcupine's quills are loosely attached and therefore detach easily when a potential predator tries to grab a bite. The quills are quite sharp at the tips and can inflict a lot of damage and be quite painful, thus deterring all but the most persistent predators.

Distribution and Habitat

Largely an inhabitant of forested areas, the North American porcupine prefers rocky areas, ridges, and slopes. It is found throughout much of North America, from the Arctic Circle into northern Mexico.

Habits and Behaviors

Porcupines are expert tree-climbers, and are as much at home in the trees as on the ground. They are also good swimmers, as their hollow quills help to keep them afloat.

Females maintain a territory, and defend it against other females. Male territories typically overlap those of several females, but the territories of dominant males rarely overlap. Juvenile males settle as permanent residents in the area of their birth, with their territories expanding in size as they mature. Females disperse from the area of their birth prior to reaching sexual maturity.

Porcupines are generally solitary, although there is some sharing of dens in the winter.


Herbaceous ground vegetation makes up the bulk of the porcupine's diet in the summer and spring, with tree-gathered vegetation forming the bulk of the fall and winter diet. Throughout the year the porcupine is more of a browser than a grazer. Most feeding is at night.


Breeding takes place in late summer and early fall. One, occasionally two, young are born after a gestation period of about 210 days. Young porcupines are born with well-developed quills and fully-functional eyes and ears, and are capable of feeding on vegetation soon after birth.

Porcupines mature slowly as compared with most other rodents, with females not reaching sexual maturity until their second fall. They also have a relatively long life span, with individual animals capable of reaching an age of 10 years or more in the wild.

Scientific Classification

Phylum Chordata
Subphylum Vertebrata
Class Mammalia
Order Rodentia
Suborder Hystricognathi
Family Erethizontidae
Genus and Species Erethizon dorsatum

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This page was last updated on February 08, 2019.