The North American Porcupine is a well-known New World rodent. This slow-moving porcupine is the second North American rodent in size only to beaver. In addition, the range of this species is the northernmost of all porcupines. The animal has short legs and heavy built. The front half of the body exhibits long, yellowish guard hairs. The back and tail exhibit dark, coarse hairs with up to 30,000 characteristic quills, scattered among them. The quills of this animal are yellowish with black tips and have stiff, barbed around 3 inches-long spines. Once thrust into another animal's skin, these spines may become fatal.
Having the northernmost range of all porcupines, these rodents occur throughout much of North America, from the Arctic Ocean to northern Mexico. They inhabit most of Alaska and Canada, the northern part of the Great Lakes region as well as the west and northeast regions of the United States. North American porcupines live in a wide variety of habitats such as dense forests, tundra, grasslands and desert shrub communities.
North American porcupines don't tend to display social behavior and are mainly found solitarily, although they do have a social structure. During the winter months, up to 8 individuals may live in the same den. During this period they are also known to forage in groups of up to 20 animals. They choose to forage in these groups in order to protect themselves from predators. However, some may prefer living and foraging alone. Each individual has its own territory, which it defends. Meanwhile, males of this species are more territorial, fiercely defending their home range. These nocturnal animals rarely go beyond their territories, except when looking for salt of apples. They communicate with conspecifics through a system of acoustic, chemical, visual and tactile signals. Thus, threatened porcupines turn away predators, using a chemical odor, which they give out by chattering their teeth. Competing males communicate through vocalizations.
The winter diet of these herbivorous animals mainly consists of tree bark. During the rest of the year, they feed upon green vegetation such as leaves, twigs and fruits, supplementing their diet by gnawing on occasional bones and antlers that are rich with mineral nutrition.
North American porcupines have a polygynous mating system, where a dominant male breeds with multiple females. Breeding occurs only if a female wants to breed. The latter tries to get pregnant by the 'best' male. North American porcupines breed between October and November. A single young is born after a gestation of 210 days. The baby is nursed for 127 days, during which period the mother provides it with required food. During the first 6 weeks, females are constantly nearby their young, meeting the babies only during the night. Mothers spend their daytime hours sleeping, while their young are hidden in a secluded place on the ground. Independence is reached at 5 months old, while the age of sexual maturity is 29 months old for males and 25 months old for females.
Currently, there are no serious threats to the population of this species as a whole, although the animals are often hunted and trapped as pests due to damaging trees, crops, car tires and other property. Population in Mexico is on the verge of extinction as a result of excessive hunting. In addition, North American porcupines suffer from collisions with automobiles.
According to IUCN, the North American porcupine is common and widespread throughout its range but no overall population estimate is available. Currently, this species is classified as Least Concern (LC) and its numbers are stable.