The Carlisle Mosquito Online

Friday, April 29, 2005



(Photo by Peter Baumgartner)
The porcupine is the first critter to make a second appearance in the Biodiversity Corner. It is not that new species are hard to find — there are thousands of unique species in Carlisle and so far we have covered only 130 — it is that when I first wrote up the porcupine we did not have a sighting, at least not by a human. A Carlisle dog had an unfortunate encounter and came home with some souvenirs. (See the online Mosquito archive for May 17, 2002.) This time we have a sighting and the only souvenirs are photographic.

Name: The common Porcupine or Erethizon dorsatum is a member of the order Rodentia — a rodent.

When and where seen: On April 15, a day when there are other things to needle us, Peter Baumgartner of Woodridge Road saw a porcupine ambling through his yard around 9 o'clock in the morning. His property connects with wild land where a porcupine could make a home and seldom be seen by humans. The dog that ran into a porcupine in 2002 lived in the area of River Road and Bedford Road.

Observation: Porcupines are chunky, slow-moving animals that have a top speed of around two mph. Peter said this one "looked like a clump of scrub brush." It walked with an awkward gait and at first came slowly straight towards him. A neighbor's dog, on a leash, caused the porcupine to have second thoughts about where it was going. It froze, then waddled off and climbed a tree. This matches the typical behavior which is neither territorial nor aggressive. The quills provide effective protection from most predators and the porcupine uses them defensively. What is not so typical about Peter's observation, is that the porcupine was out and about in daylight hours — it is largely nocturnal and only occasionally forages for food in the daytime.

Diet: Since the porcupine is strictly vegetarian, it has no need to attack other animals for food. In the winter, in the Northeast, the primary food is the eastern hemlock. If you see short sprays of hemlock twigs littering the ground, you may be in the presence of a porcupine. In the summer, the diet includes a variety of ground vegetation. Porcupines 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.

The finer points 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 is a myth that the porcupine can throw its quills; contact is necessary for the transfer. When threatened or cornered, the porcupine will turn its back and lash out with its tail. The short tail quills can be driven in quite deeply. The quills have hundreds of microscopic barbs which work to embed them ever more deeply as the victim's muscle fibers contract.

Warning: Quills should be removed right away before they penetrate further. Get professional help or use pliers. I have personal experience that says do not bother with tweezers — they are not hefty enough for the strong grasp you need to pull against the barbs. 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. There is a good online source, with photos, in the "natureworks" section of the New Hampshire public television site at

2005 The Carlisle Mosquito