PORCUPINES HAVE A POINT TO MAKE

by Whit Gibbons

August 5, 2003

Among the animals I have written about before, porcupines are near the top of my list of animals with character and admirable qualities. They don't pick fights, and they aren't bullies. But they are not pushovers either. Porcupines are usually the victors, as long as they stay away from highways. Porcupines are slow- moving mammals. After all, what's the rush? Even if a predator overtakes you, it will soon find it should have tried to eat something else.

I have an envelope full of quills I got from a live porcupine by tapping it with a wool coat. Porcupines do not sling quills through the air like darts but instead slap enemies with their tails. The quills they leave in the muzzle of a nosy dog or hungry coyote send a lasting message. They will treat a coat the same way, leaving several dozen quills that can be plucked out.

Porcupines live in the western and northern United States and far into Canada. North America has its own species of porcupine, as do the other continents, except Australia and Antarctica. Porcupines have few natural enemies and, as with most other animals these days, humans pose their greatest threat. Porcupines have little to fear from animals such as foxes or raccoons, especially after aiming a few quills toward a would-be predator's nose.

Cougars have been reported to accept a few quills to get a porcupine meal. But the big cats are rare in most areas, so their impact is minimal. The porcupine's most serious predator is an animal known as a fisher, a close relative of weasels and ferrets. However, like many fur-bearers today, fishers have been exterminated in many areas. Where fishers are rare or absent, porcupines are often common.

The tree-climbing fishers are quick and agile creatures that can successfully kill porcupines because of their speed and tactics. Porcupines discourage most predators by constantly turning and presenting their backside to an attacker. A porcupine's tail is a dangerous weapon. But the fisher moves fast, circling its prey and making quick jabs at the porcupine's face, which has no quills. A fisher usually wins the battle against a porcupine caught in the open, sort of like a mongoose versus a cobra.

The protective quills harden on baby porcupines within minutes after birth. On the day they are born they begin climbing trees and feeding on vegetation, wearing a needle-like coat of armor. The porcupine's quill is unusual in being coated with a greasy antibiotic substance. Quills that penetrate the skin of an animal can cause severe physical damage. But infection is seldom a problem because of the antibiotic properties.

Why would porcupines carry a weapon that causes temporary grief for an attacker but does not cause infection? Probably because the animal most commonly stuck by porcupine quills is the porcupine itself. These rodents, which can weigh up to ten pounds, frequently fall out of trees, breaking bones and sticking themselves with their own quills. In a study to examine healed fractures in the skeletons of wild porcupines, more than one-third of the skeletons showed evidence of broken bones. The hazard for porcupines, which enjoy a diet of leaves, fruits, and bark, comes from spending time at the end of small, fragile branches in the tops of trees. Plummeting to the ground is apparently a common event.

As with many animals living in a human-dominated world, the porcupine's primary problems begin when their natural behavior conflicts with people's interests. Two major complaints from those who live in porcupine territory are that they eat plywood and chew electrical wiring on automobiles. Humans are critical of such behavior, but the explanation for the behavior is simple. Porcupines have a liking for sodium in their diet.

The adhesive materials used to make plywood are high in salt content. Porcupines chew the wood to consume the sodium. Electrical wiring on the underside of northern vehicles has high sodium levels from being coated with highway salt during winter snow removal. Salty wires, highly desirable to a porcupine on a high-sodium diet, can take a beating from the strong teeth.

Perhaps I would be less admiring of porcupines if my vehicle or outbuildings were subject to their depredations. But I don't think so.



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