Identification

Porcupines (Erethizon dorsatum), some-times

called “porkies” or “quill pigs,”

(Fig. 1) are heavy-bodied, short-legged,

slow, and awkward rodents,

with a waddling gait. Adults are typically

25 to 30 inches (64 to 76 cm) long

and weigh 10 to 30 pounds (4.5 to 13.5

kg). They rely on their sharp, barbed

quills (up to 30,000 per individual) for

defense.

Range and Habitat

The porcupine is a common resident of

the coniferous forests of western and

northern North America. It

wanders widely and is found from

cottonwood stands along prairie river

bottoms and deserts to alpine tundra.

not unusual. How the quills are

maneuvered through the coyote’s

gastrointestinal tract is a mystery.

Porcupines are active year-round and

are primarily nocturnal, often resting

in trees during the day. They favor

caves, rock slides, and thick timber

downfalls for shelter.

Damage and Damage

Identification

Clipped twigs on fresh snow, tracks,

and gnawings on trees are useful

means of damage identification.

 Trees are often deformed from partial

girdling. Porcupines clip twigs and

branches that fall to the ground or

onto snow and often provide food for

deer and other mammals. The considerable

secondary effects of their feeding

come from exposing the tree

sapwood to attack by disease, insects,

and birds. This exposure is important

to many species of wildlife because

diseased or hollow trees provide shelter

and nest sites.

Porcupines occasionally will cause

considerable losses by damaging

fruits, sweet corn, alfalfa, and small

grains. They chew on hand tools and

other wood objects while seeking salt.

They destroy siding on cabins when

seeking plywood resins.

Porcupines offer a considerable threat

to dogs, which never seem to learn to

avoid them. Domestic stock occasion-ally

will nuzzle a porcupine and may

be fatally injured if quills are not

removed promptly

.

Legal Status

Porcupines are considered nongame

animals and are not protected.

Food Habits

Porcupines eat herbaceous plants,

inner tree bark, twigs, and leaves, with

an apparent preference for ponderosa

pine, aspen, willow, and cottonwood.

Trees with thin, smooth bark are pre-ferred

over those with thick, rough

bark. Porcupine feeding is frequently

evident and has considerable impact

on the cottonwood stands of western

river bottoms.

General Biology, Reproduction, and Behavior

Porcupines breed in autumn, and after

a 7-month gestation period usually

produce 1 offspring in spring.

Although the young are capable of

eating vegetation within a week after

birth, they generally stay with the

female through the summer. Juvenile

survival rates are high.

Predators of porcupines include

coyotes, bobcats, mountain lions, black

bears, fishers, martens, great horned

owls, and others.