Porcupines

Dec 02, 2010

by Steve Blight

Drawing: Porcupine quill, Hinterland Who’s Who, Canadian Wildlife Service, Environment Canada. Reproduced with permission of the Minister of Public Works and Government Services, 2005.

The porcupine is a common and well-known animal in Canada and across much of North America, and is no stranger to most people in the Land O’ Lakes area. The porcupine is Canada’s second largest rodent, next to the beaver. Adult males reach an average weight of 5.5 kg (about 12 lb.) after six years; the females reach 4.5 kg (10 lb.).

Its fame stems mainly from its quills, which keep most enemies at a respectful distance. Unfortunately quills are no defence against vehicles and the slow moving porcupine often falls victim to traffic.

The quills are longest on the back and tail, with quills on the back reaching 12.5cm in length. There are no quills on the muzzle, legs, or under parts of the body. Each quill is hollow and is attached to a small muscle that pulls it upright in the fur when the animal bristles with alarm. Near the tip, the quill tapers to a fine point closely covered by several dozen small black barbs. These barbs feel only slightly rough to the touch, but when they are wet -- as when embedded in flesh – they swell, working the quill farther in.

It has been estimated that the porcupine has over 30,000 quills, so it is not out of ammunition after a single encounter with an enemy, when several hundred quills may be dislodged. As the quills are lost, they are replaced by new ones, which are white and sharp and which remain firmly anchored in the skin until they are fully grown.

My most memorable encounter with a porcupine happened a few years ago when I was out walking with our dog on our property east of Sharbot Lake. Always curious, she got up close and personal with a porcupine and was rewarded with a snout full of quills. She came whimpering back to me, furiously pawing at her face trying to make her pain go away. I grabbed her, put her in a headlock and pulled out the quills one by one with my fingers. She was soon running around the bush again, seemingly none the worse for wear. Hopefully she learned her lesson and will leave porcupines alone. I learned my lesson too – I now carry tweezers and pliers with me when I’m in the bush with the dog.

Porcupines generally live among trees and are most common where there are rocky ledges and rock piles suitable for dens. They are strictly herbivores, in winter feeding largely on the inner bark of trees – a habit that is not always appreciated by landowners because of the damage this does to their trees. In our area, white pine and hemlock are said to be favourites, but the bark of most trees is acceptable. Last winter I regularly saw a porcupine feeding on the bark in the crown of a red oak. When the sap rises in spring, the bark of maples is favoured. In summer, the porcupine will also eat the leaves of low growing plants and a diverse range of trees and shrubs.

One of the porcupine’s best-known but least-liked eating habits is that of chewing plywood, tool handles and leather. It gnaws both salty and non-salty objects, which indicates the habit may stem not only from a craving for salt, but also from a need to hone the continuously growing teeth. When human-made objects are not available, the porcupine will chew bones and cast-off antlers.

Across North America porcupines have a number of predators including coyotes, cougars, bobcats, red foxes, lynxes, bears, wolves, fishers, and Great Horned Owls. Some predators learn to avoid the quills and kill the porcupine by biting its head or by flipping the porcupine onto its back to expose the unprotected belly. The fisher is the best-known porcupine hunter.

During winter the porcupine does not hibernate. However, it does not usually move far and feeds within 100 m of its den. In winter it will feed at any time of the day or night, but during the rest of the year it is nocturnal. In winter when the snow is soft and deep, the porcupine trail resembles a kind of trough through the snow. I’m hoping there’s lots of snow this winter to do some porcupine tracking!

Please feel free to report any observations to Lorraine Julien at This email address is being protected from spambots. You need JavaScript enabled to view it.  or Steve Blight at This email address is being protected from spambots. You need JavaScript enabled to view it.