Erethizon dorsatum
(Common Porcupine)

Order: Rodentia
Order Description:Rodents
Family: Erethizontidae
Family Description: Porcupines

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

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

Prefers coniferous and mixed forests. In some parts of range, also found in riparian Click word for definitionzones, grasslands, and shrub steppe.

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.

Mainly nocturnal Click word for definition, 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.

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

Status: Game species

Global Rank:


State Rank:


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.

Information written by Donald Streubel,© 2000
Photos by Kris Wilcox and from Yellowstone- National Park Service, May 1998.
Map image provided by
Stephen Burton, 2000
Design by Ean Harker 1999, 2000, 2001.