Porcupine
Last Review/Updated: May 31, 2002
Erethizone dorsatum
The porcupine is a large, robust rodent. Adults weigh about 10 kg (22 lb.). The porcupine has a thick tail, and short powerful legs with long curved claws. The unique coat is composed of rows of dense, brown undercoat with yellow-tipped guard hairs. These alternate with rows of loosely attached quills that vary from 25 to 65 mm (1 to 2.5 in.) in length. The quills taper to a sharp and stiff point that is covered with very small barbs. The quills are hollow, thus reducing their weight and providing buoyancy when the animal occasionally swims.
Porcupines live by themselves, except during mating season in November and December. Usually only one porcupine is born to each female from mid-May through July. The porcupine is the only North American rodent to give birth to precocial young. The young are born covered with hair and quills, with eyes open, and they are able to move about soon after birth. The quills are flat and limp at birth but soon dry in the air. Young porcupines are quite large at birth, weighing about 500 grams (1.1 lb.). Young follow their nomadic mothers for several weeks, although they are weaned in their second week.
In summer porcupines feed on green leaves of forbs, shrubs and trees. They climb trees with ease and spend much of their time foraging in the trees. In winter they feed on the inner bark (cambium), twigs and buds of trees. They occur in all life zones where there is sufficient vegetation, including the alpine in summer.
