New World Porcupines: Erethizontidae

Physical characteristics: North American porcupines have stiff, dark-brown or black hair on their back along with scattered white barbed quills at the head, rear of body, and on the tail. They may have more than 30,000 barbed quills, many of which have a yellow-white base with a dark tip. Their face is a dark brown, with a woolly belly that does not have quills. Their undersides are covered with stiff, dark hairs. North American porcupines have a short, thick tail that contains quills above and stiff bristles below and large, naked feet. Their large incisor teeth are deep orange. Adults have a length of about 39 inches (1 meter) with the tail being one-fifth to one-third of the total length. Body weight is less than 26 pounds (12 kilograms), but a large male can be up to 33 pounds (15 kilograms). Juveniles Most of the time, North American porcupines do not communicate, but mothers do touch their young with their nose, giving them gentle grunts and whines. (D. Robert Franz/Bruce Coleman Inc. Reproduced by permission.) have a nearly all-black head, back, and tail. Their quills are short but sharp. Females have two pairs of mammae (MAM-ee), milk-secreting organ of female mammals.

Geographic range: North American porcupines range throughout Canada, except the far north-central regions, and down into the northeastern and north-central part of the United States and almost all of the western United States except the most southern regions. They also extend into the northern edge of central Mexico.

Habitat: North American porcupines are found in mixed hardwood and softwood forested areas, tundra, and occasionally in open areas and even deserts as long as plenty of water sources are around. They prefer rocky areas, ridges, and slopes.

Diet: North American porcupines are herbivores, animals that eat plant material, such as fruits, grains, and seeds. They feed on foliage for much the year and on inner bark of pine and oak trees in winter. They also eat seeds, fruits, nuts, berries, and plant stems, buds, twigs, leaves, roots, and flowers. Their chisel-like teeth scrape away the tough outer bark, and then slice off pieces of inner bark to eat. North American porcupines eat alone, except for mothers and their young. They feed at night, but sometimes during the day, especially if the weather has been bad.

Behavior and reproduction: North American porcupines are mostly arboreal and nocturnal animals. They are good at climbing trees, although their slow movements seem awkward, and are good swimmers. They use hollow trees and logs, or gaps beneath rocks for their winter dens. The animals normally live alone, but will share a winter den when few good locations are available. They are not territorial, but will defend a feeding site if resources are few. During the breeding season, females produce bodily odors to show males they are ready to mate. Several males fight over the right to mate with one female. One of their courtship rituals is for the male to spray the female with urine. When females are ready, they will dance with their chosen male, rising on their hind feet, embracing while whining and grunting loudly, and pushing one another playfully to the ground. Their main predators include mountain lions, lynx, fishers, coyotes, bobcats, red foxes, wolves, wolverines, and great horned owls. During winter months they stay close to their den but go further out during summer months.

They are polygynous (puh-LIH-juh-nus), having more than one mate. Mating occurs only once a year, in the late summer and early autumn, and only during an eight to twelve hour period when the female is receptive. Females give birth to one but sometimes to two young. The gestation period is about seven months. Young weigh about 1.0 to 1.1 pounds (450 to 490 grams) at birth, and are born with both spines and fur. They double their weight within the first two weeks. They usually feed on their mother's milk for only a short period then begin to feed on vegetation shortly after birth. They soon become entirely independent of the mother. Young males move in and out of the mother's range for months or years, while young females leave the range permanently. They become sexually mature at about one-and-a-half years and most can live to about fifteen years of age.

North American porcupines and people: Native Americans used their quills for artwork and as a type of currency. North American porcupines were also hunted for food. They are often considered as pests when they gnaw through valuable wood and trees.

Conservation status: North American porcupines are not threatened. ∎