The North American porcupine (Erethizon dorsatum) is a New World porcupine widely distributed in North America (Canada, the United States, Mexico). Body length is 60–90 cm, tail about 20 cm, and it has many quills (approximately 30,000). When threatened it raises its quills and hair, turns its back, and defends itself by charging. It is primarily herbivorous, eating bark and cambium, leaves, roots, berries, and other plant matter depending on the season. Nocturnal and solitary, it uses both trees and the ground and does not hibernate in winter. Breeding occurs from September to December; gestation is about seven months, and typically a single well-developed young is born. Overall the population is stable and it is of Least Concern.