A Prickly Subject

close up of a North american porcupine foraging with trees and fall foliage in the background

This article was originally published in the Winter 2002/2003 edition of Teton Valley Top to Bottom magazine.

From the creosote deserts of northern Mexico and the southwestern United States up the length of the Rockies and across the northern sweep of the continent wanders a remarkable, independent creature so curious an invention of nature it seems the stuff of fairy tales. This brownish, smallish, rounded being with orange teeth and bright brown button eyes waddles along on all fours, covered from head to toe with 30,000 quills. It’s the porcupine, a long-time denizen of Teton Valley.

Hidden among a soft, brown, woolly undercoat and covered by long guard hairs, the quills are a marvel of protection for this otherwise docile, defenseless animal. When threatened, the porcupine’s first instinct is to make an ungraceful beeline for the nearest shelter or tree, even breaking into a clumsy sort of gallop as it heads for safety. If trapped, however, it will hump its back, tuck its vulnerable nose down between its shoulders, pivot rapidly on its front feet and present its back to the enemy. Stomping its rear feet, it will lash its powerful tail back and forth. But contrary to popular perception, the porcupine cannot throw quills. It perpetuates that myth only when a few loose quills detach from its tail and fly through the air.

Mature quills detach easily. The tips are covered with hundreds of microscopic barbs that point backward. As they pierce the skin of the attacker, the barbs expand with body heat and moisture, and inexorably work in deeper. In one day, they can penetrate up to an inch. Driggs veterinarian Don Betts once found a quill in a uterine ligament during a spay operation. Another was found in a dog five years after its encounter with a porcupine. Wild animals generally do not make the mistake of trying to play with or make a meal of the porcupine more than once—unless they are skilled predators. The cost-benefit ratio isn’t in their favor. If the quills enter a vital organ, the animal will die. If its mouth is filled with quills, it will starve.

The quills are actually modified hairs filled with a spongy matrix. They cover a porcupine’s body from head to toe except for its face, belly, and short legs. Quills from different parts of the body vary in length, color, diameter, and length of the barb. The shortest ones are found on the cheeks. The longest ones, found on the rump, can grow to 4 inches. Lost quills are replaced during the annual molt—they can take from two to eight months to reach full size and stiffness. Under normal circumstances quills lie flat, but at any sign of danger, special muscles erect them in a flash. Should a predator try to capture a treed porcupine, it will back down toward the assailant, flicking and lashing its tail and chattering its teeth.

But in nature, no armor is fail-safe, and a surprising number of predators do make an occasional meal of a porcupine, including cougars, coyotes, bobcats, wolves, minks, wolverines, ermines, weasels, red foxes, bears, lynx, eagles, and great horned owls. The fisher counts eating porcupines among its specialties. A fisher will circle a porcupine until it sees an opportunity to bite its nose; after repeated bites, the fisher will find an opportunity to flip the porcupine onto its back so it can attack the quill-free underbelly.

Trapping and deforesting of their habitat caused a dramatic decline in fishers in the United cares. Once found throughout the forested regions of the northern United States and in the mountainous areas of the West, fishers are now extremely rare. The consequent increase in the number of porcupines, which girdle trees (strip bands of bark off them), caused the animals to be labeled pests, an attitude that has persisted through generations.

However, the actual amount of damage done by porcupines is probably exaggerated. One study in a red spruce area in Maine, with 20 to 28 porcupines per 2.5 square kilometers (just under one square mile), showed only a half percent loss of trees. But perceived as pests, porcupines are nonetheless shot, trapped and poisoned using salt baits. Humans have other options, however. They can protect their orchards and decorative trees with metal tree guards and electric fences, for example. Porcupines do serve their purpose by earing mistletoe, a parasite on trees, and indulging in a habit of thinning out dense stands of saplings.

Porcupines don’t hibernate, and the main food available in deep snow is the nutritious inner bark of trees. This isn’t their preferred food—when given a chance, porcupines slowly and deliberately forage on the ground, relying on their excellent nose to select delicious and succulent plants, including flowers, roots, stems, berries, seeds, nuts, twigs and buds. Excellent swimmers, porcupines also include juicy aquatic plants in their diet. While they are slow and deliberate, they are also persistent: porcupines may forage over many acres as they search for the best morsels.

Porcupines aren’t dainty eaters: their noisy, sucking enjoyment carries over long distances. In general porcupines can be quite vocal, especially when something arouses their displeasure (e.g. their intended path is blocked) or their pleasure (as when they approach a particularly succulent morsel). Vocalizations include moans, grunts, wails, whines, shrieks, whimpers, and screams.

In winter the porcupine’s range is much more restricted and tends to be dictated by the nearness of good food trees and simple den sites, which may be used for generations. They may at times shelter together. Exploring a rocky mine shaft one day, Jean Simpson of The Wild Bunch Ranch near Tetonia found five porcupines, still as statues, each with its nose to the wall. The temperature was 30 degrees below zero outside, but it was quite comfortable inside.

Females are generally territorial, driving other females out of their home range. Males have much larger, overlapping ranges and seek out the females when mating time arrives in the fall. Mating is a lengthy and noisy affair accompanied by loud screams, whines, and grunts. The single baby is born 210 days later with its eyes open and teeth already exposed. Soft at birth, the quills harden within the hour. The porcupette will nurse for four to six months as it travels with its mother, searching out the good den sites and food sources.

Porcupines’ known penchant for chewing wood and leather items around homes and camps has contributed to the perception of these creatures as pests. Biologists believe the vegetarian animals need extra sodium to balance their cell potassium levels. Choice treats include perspiration-stained boots, tool handles, and some paints and glues. They also chew on non-salty items to hone their two front teeth. The porcupine belongs to the order Rodentia, and like all rodents, including beavers, their large front gnawing teeth continue to grow as long as they live. Porcupines have an estimated life span of five to six years in the wild, 10 to 20 years in captivity. If they survive to maturity, they can weigh 10 to 40 pounds.

The porcupine, which has been on Earth since the Oligocene Epoch 23 to 38 million years ago, is a gentle creature that takes great, if simple, joy in life. Perhaps, with a spirit of understanding, human society can afford a few girdled trees and exercise a little caution when venturing into the woods with domestic dogs. And those lucky enough to hear the sucking, chewing sounds of uninhibited delight can cake pleasure in knowing there’s a brownish, smallish being with orange teeth and bright button eyes nearby.

If your dog tangles with a porcupine, it’s important to remove the quills quickly. They can be pulled out with a pair of pliers, but if they become deeply embedded, the animal will have to be anesthetized before the quills can be removed. Veterinarian Don Betts cautions against cutting the quill ends off, explaining that it does not relieve pressure and only makes removal harder.

You don’t have to kill a porcupine if you want quills for earrings, decoration of clothing, or artwork. You can corner one instead, tapping its back with a Styrofoam paddle to collect hundreds of quills.

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