Erethizon dorsatum
(Common Porcupine)

Description:
Roughly about the size of a small to mid-sized dog. Brown fur laced with long quills used in defense.

Range:
Throughout Canada, northern Mexico, and U.S. (absent from southeastern U.S.) In Idaho.

Habitat:
Prefers coniferous and mixed forests. In some parts of range, also found in riparian zones, grasslands, and shrub steppe.

Diet:
Feeds on inner bark of trees and on evergreen needles in winter, buds in spring, roots, leaves, berries, fruits and seeds in summer, and mast and fruits in fall.

Ecology:
Mainly nocturnal , but frequently seen during day. Active year-round in southeastern Idaho. Winter den sites include rock outcrops, live hollow trees, hollow logs, and outbuildings; may also shelter in dense conifers. Summer range may average up to 50-100 ha; winter range may be less in presence of extensive snow cover. In southeastern Idaho study, winter home range was reported at 0.07 ha, and summer home range was 23.1 ha for females. Densities may vary from 9-22/km² in good habitat. Species is preyed upon by felids, canids, mustelids, and raptors.

Reproduction:
Breeds September-December. Gestation lasts 17-18 wk (usually 210 days). Female rears 1 young each year; young reaches sexual maturity in 15-16 mo.

Conservation:

Status:	Game species
Global Rank:	G5
State Rank:	S5

Important State References:
Craig, E.H. and B.L. Keller. 1986. Movements and home range of porcupines, Erethizon dorsatum, in Idaho shrub desert. Canad. Field-Natur. 100:167-173.