(Erithizon dorsatum dorsatum)
Adult porcupines on the average weigh from 4 to 6 kg, and are from 60 to 100 cm long. This is the only mammal in North America that has coat hairs which are modified as quills. The coat tends to be dark colored, although chestnut, cream, brown, gray, and albino porcupines have been seen. The porcupine has a small face, with a blunt muzzle, and a tapering head and neck. The tail is short and stout. The feet of the porcupine resemble those of a bear, with four long claws on the front feet and five on the hind feet. Breeding season is from September to November and one precocial pup is born in late April or early May. Porcupines are nocturnal and tend to be solitary except during the breeding season, but they may den together in the wintertime. Having poor vision, porcupines rely primarily on their good sense of hearing and of smell, sometimes standing up on their hind legs to sniff the air. They remain motionless when mildly threatened, but when they feel that they are in greater danger, they will erect their quills and seek a sheltered place to protect their head. Vocalizations of the porcupine, though used infrequently, include various screeches and calls.
They are no longer present in Virginia. Porcupines occupy a variety of habitats, from tundra to desert, from grassland to forest, across the western and northern United States. In the east, they are rare south of Pennsylvania.
In the winter, they eat the cambium, phloem, and leaves of woody shrubs and small trees, especially hemlock. In the spring and summer, porcupines feed primarily on the ground, consuming various forbs and grasses, including sedges, dandelions, violets, clover, alfalfa, and grains.