Classification and Range
The North American porcupine is second only to the beaver as the largest rodent native to this continent. Porcupines are members of order Rodentia, suborder Hystricognathi (porcupines) and family Erethizonidae. They are four genera: Coendou, Echinoprocta, Erethizon and Sphiggurus, with 12 species. Porcupines are distributed in the Americas, Africa and Asia. The North American porcupine is found in the United States, Canada and northern Mexico.
Porcupines prefer forests with both hardwood and softwood trees, though they may be found in desert chaparral in northern Mexico.
Adult length: 31-40 inches (78-100 cm)
Tail length: 7-11 inches (17.5-28 cm)
Shoulder height: Up to 12 inches (30 cm)
Adult: 7-15 pounds (3-7 kg); males have weighed as much as 40 pounds (18 kg)
Up to 10-15 years in the wild; 10 years or more in captivity
In the wild: Year round diet of the bark and cambium layer of many different trees. Spring and summer diet consists of grasses, buds, twigs, roots, leaves, flowers, seeds and an assortment of other vegetation. Bones and antlers found on the ground are eagerly gnawed for their high mineral content. Winter diet consists primarily of conifer needles and the tree bark of conifers and hardwoods.
At the zoo: Commercially prepared rodent diet, plus assorted vegetables and fruits including carrots, yams and apples.
Female porcupines become sexually mature at about 18 months of age. The breeding season occurs between September to November and females may cycle more than once a year. Gestation varies from 205 to 215 days. One pup or "porcupette" is born in the spring (usually late-April to early-May,) However, pups can be born as late as August. Newborn pups weigh about 1 pound (.45 kg) and are approximately 10 inches (25 cm) long.
Young are born with eyes open and teeth erupted. Their bodies are covered with long hairs and quills, which are fully functional after drying within a few hours. Newborn are born mobile and capable of following the female. Young porcupines nurse about two months, but begin feeding on vegetation after only the first few days of life. Young usually stay with the female through the summer and then are on their own. Coloration of young porcupines usually darkens with age, and they reach full adult size in three to four years. While very nearsighted, porcupines have keen senses of smell, hearing and touch.
Its name comes from Latin for "swine" and "thorn." The porcupine has 30,000 or more quills, which cover all its body except the snout, throat, belly and feet pads. Quills are modified hairs with hollow, spongy centers. The loosely attached quills easily embed in attackers upon contact. While the porcupine does not throw quills, the flailing muscular tail and powerful body may help impel quills deeply into attackers. The quills' barbed ends expand with moisture and continue to work deeper into flesh. Porcupine quills have mildly antibiotic properties and thus are not infectious. Quills may cause death if they puncture a vital organ or if a muzzle full of quills leads to starvation.
How do Porcupines Mate? Very Carefully!
Males fiercely compete for breeding rights. Hostility and violent battles are common with vicious bites, hundreds of "foreign quills" exchanged and even fatalities. Courtship consists of a period of wrestling, chases, vocalizations and urine showers. A receptive female folds her quills flat against her body, elevates her rear and arches her tail over her back. This provides the male with a quill-less platform. Mating continues until one of the pair ends contact by climbing a tree or hostile screaming.
A Mostly Quiet Life
Porcupines are generally solitary in nature, although groups up to a dozen may gather at certain nocturnal feeding sites during summer and early autumn. Numerous porcupines may share a den on a rotating basis, and several may share a winter den at the same time. During autumn breeding season, a number of males are found around adult females in estrus. During the summer, the nocturnal porcupine often spends the day resting safely in trees. Despite its stout body, short legs and waddling gait, the porcupine scales trees to great heights, climbing in an awkward and slow manner. The strong and barbed tail acts as a fifth leg for climbing, as well as a tripod-like prop for sitting upright. If alarmed, the porcupine will present its back with quills erected. Fishers, bobcats, cougars, coyotes, wolves and wolverines prey on porcupines. Great horned owls prey on young. The fisher is an especially successful predator. It launches frontal attacks on the unprotected snout, then a weakened or shocked porcupine can be flipped over, exposing its belly.
Location at the Zoo
Woodland Park Zoo's porcupines are located in the award- winning Northern Trail. During the summer look up in the trees to find the resting porcupines.
Porcupines are a very successful species and are not endangered. Nonetheless, porcupines have enemies, humans being the most lethal. Besides becoming "road kill," porcupines are targeted due to certain destructive behaviors. The timber industry targets the porcupine because of its year round taste for trees. Agriculturists also consider the porcupine a pest when it forages on crops such as corn. A desire for salt leads porcupines to gnaw on objects as varied as vehicle tires for road salt or axe handles for salty human perspiration. Humans have used bounties and poisoning against porcupines to control their numbers. During the 1950s and 1960s, reintroduced fishers successfully reduced porcupine populations in programs in states from Oregon to Vermont.
How You Can Help!
Although the porcupine is not considered endangered, many other plant and animal species are in peril. The effort to save endangered species requires cooperation and support at the individual, regional, national and international levels. You can help in this cause. Join and become active at Woodland Park Zoo and other conservation organization of your choice. Let your elected representatives know your views on protecting endangered species and wild habitats.
Contact Woodland Park Zoo at firstname.lastname@example.org find out other ways you can support conservation programs at the zoo. Learn other ways you can help conserve wildlife and the habitats they require for survival by visiting our How You Can Help page.
Sources and Suggested Reading
Dodge, Wendell E. "Porcupine." In Chapman, Joseph A. and George A. Feldhamer, ed. 1982.
Wild Mammals of North America: Biology, Management, Economics. The John Hopkins University Press, Baltimore, MD. 1,147 p.
Macdonald, David, ed. 1999. The Encyclopedia of Mammals. Barnes & Noble Books, New York, NY. 895 p.