Common porcupine (Erethizon dorsatum)
In Oregon, the porcupine is found throughout most of the state east of the Cascade Range. Porcupine attains its greatest abundance in mixed coniferous and hardwood forests. Their diet varies seasonally. During winter, they consume the inner bark of trees and the needles of conifers. In spring and summer, they feed on developing buds, roots, grasses, leaves, berries, and fruits. They also eat acorns and some seeds.

Porcupines do not hibernate and are active throughout the year. Activity is mostly nocturnal, but those feeding in trees may be observed at any time as they usually do not retire to dens during the daylight hours. Some use is made of dens in winter.

Porcupines make a variety of vocalizations and sounds with the teeth, some which can be heard at considerable distance. 

They seemingly are intelligent and are able to learn quickly; they have good memories and especially remember being mistreated.