The Carlisle Mosquito Online

Friday, May 17, 2002


Biodiversity Corner Porcupine

Name: Common Porcupine or Erethizon dorsatum. Member of the order Rodentia. ­ a rodent.

Evidence: Several porcupine quills found in a dog by Sally Lakness, Carlisle Animal Inspector, May 5. The dog had not been out of town so the porcupine must have been here ­ in the area of River Road and Bedford Road.

Other signs of porcupines: If you notice bark chewed off the higher reaches of tree trunks, piles of scats like brown elbow macaroni in hollow logs or trees, or short sprays of hemlock twigs littering the ground, you may be in the presence of a porcupine.

Distinguishing characteristics: A chunky animal up to 20 inches long, not counting the tail. Weighs 10 to 28 pounds. Has long black and dark brown guard hairs covering the body. Quills are mixed with the hair and are most dense on the back and the upper surface of the tail. There are no quills on the face, the belly or the insides of the legs. The porcupine I saw once on a ski slope in Vermont looked like a big fur hat.

Behavior: A solitary, slow-moving animal; it can waddle at speeds reaching 2 mph ­ it wouldn't win a race against anything much other than a fur hat. It is not territorial or aggressive, prefering retreat to confrontation. It is largely nocturnal and makes its den in rock crevices, caves, old dens of other animals, hollow logs, or under houses or barns. The breeding season is between September and December and a single baby - a porcupette - is born around May or June.

Diet: Strictly vegetarian. In the winter, in the Northeast, the primary food is the eastern hemlock. In the summer, the diet includes a variety of ground vegetation. They have a fondness for salt and will gnaw on objects like the wooden handles of garden tools, axes or paddles that have traces of salt from human sweat.

Predators: Notably fishers, but also great horned owls, coyotes, bobcats, mountain lions and wolves.

Department of Defense: Quills are modified hairs, up to three inches long, solid at each end, and hollow for most of the shaft. The porcupine has 30,000 or more quills and can easily spare a few. It's a myth that the porcupine can throw its quills; contact is necessary for the transfer. If you get too close to a porcupine it may lash out with its tail and if it should make contact, some of the quills - which are loosely attached to the porcupine - may become firmly and painfully attached to you. The short tail quills can be driven in quite deeply. The quills have hundreds of microscopic barbs which work to embed the quills even more deeply as the victim's muscle fibers contract.

Warning: If you can't get professional help to have quills removed right away, pull them out with pliers before they penetrate further. They can be fatal if they pierce a vital organ. If you can cut the protruding end off the quill back to where it is hollow, and still leave enough to grasp with the pliers, this will release internal pressure and help in the removal.

References: Donald and Lillian Stokes, "Guide to Animal Tracking and Behavior"; National Wildlife Federation at (enter Erethizon in the search window).

I pine for your ideas and sightings for next week's sequel to the porcupine. I don't want to needle you but please send a note, a photo, an idea or a whole column to Kay Fairweather at 392 School St, Carlisle MA 01741 or to

2002 The Carlisle Mosquito