Porcupines do not hibernate. Porcupines are solitary in summer. Throughout the year they do most of their feeding and moving about at dusk, during the night, and at dawn. In Pennsylvania, porcupines are preyed upon by fishers, and to a lesser extent, foxes, coyotes, bobcats, dogs and owls. The fisher, reintroduced in Pennsylvania in the mid 1990s, has mastered the technique of flipping a porcupine onto its back, exposing the rodent's unquilled, vulnerable belly, and killing it with a swift bite.
Fishers also kill porcupines with repeated bites to the face and head.
Also, coyotes have been known to work in pairs to maneuver a porcupine onto its back. Porcupines are parasitized by lice, ticks and mites, some are afflicted with mange, and many have tapeworms and other internal parasites. In our state, most porcupines live in areas of extensive forests. Few, if any, porkies live in the southwestern or southeastern parts of the state. Mammalogists have theorized that the porcupine originated in South America, crossed the Isthmus of Panama during the Pleistocene period, and overspread North America.