by Whit Gibbons

February 8, 2009

Among the myriad animals I have been asked about, porcupines are near the top of my list of favorites. They don't pick fights and are never 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 be looking elsewhere for a meal. These are some of the questions I have been asked over the years.

Q. I know that armadillos and coyotes were not native in the South east of the Mississippi River only a few years ago, but now they seem to be in most southern states. Are porcupines also invading the Southeast? Can they survive our hot summer temperatures?

A. The answers are no and yes. Porcupines occur naturally in the western and northern United States, from Alaska to Pennsylvania and far into Canada. They have not appeared in any of the southern states, except for mountains in Virginia, but you are correct that armadillos and coyotes are relatively recent migrants to many areas of the Southeast. Despite living in some of the coldest regions on the continent, hot summer temperatures are not a show-stopper for porcupines. Their range in the Southwest extends to California and into Mexico. This past summer I saw three alongside roads in the very hot deserts of New Mexico.

Q. Aren't porcupines a terrible pest in areas where they occur?

A. As with many animals living in a human-dominated world, porcupines earn the title of pest as soon as they do anything that does not suit people who occupy the same area. Two major complaints from those who live in porcupine territory are that they eat plywood and chew electrical wiring on automobiles. 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. Porcupines also eat bark and quickly become unpopular when they eat someone's newly planted saplings.

Q. Since I have never heard of a porcupine without quills, I assume they must grow back when they lose them. How long does it take? Also, do the quills cause serious infection when stuck in a person's skin or a dog's nose?

A. 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. Quills are of the same origin as the tough, outer guard hairs on dogs and other mammals that have thick coats. The hairs grow back when they are removed or, in the case of quills, when they are stuck into a predator. A long quill probably takes several days or even weeks to grow back completely. Typically porcupines have an average of about 30,000 quills, so they always have a good supply to take care of a pesky dog or person. The quills generally do not cause infection because they have an antibiotic coating. The sticking itself hurts plenty, and the tips of quills can even break off under the skin. But because of their antibiotic properties porcupine quills create fewer problems from infection than a wood splinter.

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

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