PORCUPINES - THE UNSUNG WONDERS AMONG US

©By Susan B. Eirich, Ph.D.

From the creosote deserts of the United States and northern Mexico up the length of the Rockies and across the northern sweep of Canada and the United States wanders a remarkable, independent, solitary creature, so curious an invention of nature that it might exist only in a fairytale. It is a brownish smallish rounded being with orange teeth and bright brown button eyes found waddling clumsily along on all fours, covered from head to toe with 30,000 quills. This is the porcupine, one of the denizens of Teton Valley.

Hidden among the soft brown wooly undercoat and covered by long guard hairs, the quills are a marvel of protection for this otherwise docile, defenseless animal. The porcupine's first line of defense 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. But if trapped it will hump its back, tuck its vulnerable unprotected head down between its shoulders, pivot rapidly on its front feet, and present its back to the enemy. Stomping is back feet it will lash its powerful tail back and forth. It is the lashing tail that is the business end of the porcupine. But contrary to popular conception it cannot throw its quills. The closest the porcupine comes to that myth is if a few loose quills detach and fly through the air as it vigorously lash their lashes its tail.

Matured quills in the tail detach easily. The tips are covered with hundreds of tiny microscopic barbs that point backwards. As they pierce the skin of the attacker the barbs expand with body heat and moisture and inexorably work in deeper and deeper. In one day they can travel 2.5 cm. Local vet Don Betts has found one in a uterine ligament during a spay operation...another quill was found in a dog five years later. Unlike domestic animals, wild ones do not generally make the mistake of trying to play with or make a meal of porcupine more than once, unless they are skilled predators. The cost benefit ratio is not in their favor. If the quills enter a vital organ the animal will die. If their mouth is filled with quills they will starve to death. And wild animals do not have an owner to pull them out or take them to the vet.

The quills are actually modified hairs filled with a spongy matrix. They cover the body from head to toe except for the front of the face, belly, and inside of their short little legs. Quills from different parts of the body vary in length, color, diameter and length of the barb. The shortest ones are found around the head. The longest ones can be 8-10 cm. Lost quills are replaced during the annual molt - they can take from 2 to 8 months to reach full size and stiffness. Under normal circumstances they lie flat but at the sign of danger special muscles erect the quills in a flash. Should a predator try to capture a treed porcupine it will back down towards the assailant flicking and lashing is tail, and chattering its teeth.

There are a surprising number of predators that do make an occasional meal of porcupine - these include cougars, coyote, bobcat, wolves, mink, wolverine, ermine, weasel, red foxes, bears, lynx, eagles and great horned owls. They succeed by either biting its head, or flipping the porcupine over to attack the quill free underbelly. As always in nature, no armor is completely fail safe - there is always something that evolves to pierce it. In the case of the porcupine it is the fisher (black marten), which counts among its specialties eating porcupines. It will circle the porcupine until it can finds an opening to bite it's nose - after repeated bites it will find an opening to flip it over. European colonists caused a dramatic decrease in fishers by trapping them and by deforesting a good part of their range. Found in the forested areas of the northern United States and in the mountain areas of the west, fishers are now extremely rare. The consequent increase in the number of porcupines girdling trees caused them to be labeled pests, an attitude which has persisted through generations. The actual amount of damage done is probably exaggerated...one study in a red spruce area in Maine, with 20-28 porcupines per 2.5 square kilometers, showed the loss of trees was only 0.5 percent. However because of the perception that they pests they are shot, trapped, or poisoned using salt baits. There are other options to protect human assets such as orchards or decorative trees, for example metal tree guards and electric fences. And porcupines serve their purpose in the scheme of things eating mistletoe, a parasite on trees, serving as an emergency dinner to many wild things in times of hardship, and indulging in a habit of thinning out dense stands of saplings.

The girdling of a tree in a result of the porcupine's winter diet. They do not hibernate, and the main food available in the deep snows is the nutritious inner bark of trees. This is not their preferred food - when there is a chance they are most often found slowly and deliberately foraging on the ground relying on their excellent nose to guide in the selection of delicious and succulent plants - flowers, roots, stems, berries, fruits, seeds, nuts, dandelions, skunk cabbage, twigs and buds. Also included in their diet are juicy aquatic plants - they are excellent swimmers. They may be slow and deliberate, but they are also persistent - their daily foraging may cover up many hectares as they search for the best morsels. And they are not silent eaters - one can hear their noisy, sucking enjoyment for quite a distance. In general porcupines can be quite vocal, as when something incurs their displeasure, (their intended path is blocked), or their pleasure, (approaching a particularly succulent morsel). Vocalizations include moans and grunts and wails and whines and shrieks and whimpers and screams.

In winter their range is much more restricted and tends be dictated by the nearness of good food trees and simple den sites that may be used for generations. They may shelter with other porcupines. Jean Simpson of The Wild Bunch Ranch explored a rocky mine shaft one cold winter day. At the end he found five porcupines, still as statues each with their nose to the wall. It was 30 below zero outside, but comfortable inside.

Females are generally territorial driving any other females out of their home range. Males have much larger, overlapping ranges and it is they who seek out the females when mating times arrives in the fall. Mating has been observed to be a lengthy and noisy affair accompanied by loud screams and whine and grunts. The single baby is born 210 days later, eyes open, teeth already exposed. Soft at birth, the quills harden within the hour. The porcupette (really) will nurse on its mother for 4-6 months as they travel together, and she shows her infant the good den sites, foods, and food trees.

The other habit for which they are branded as pests is their known penchant for chewing wood and leather items around homes and camps. Biologists believe they need the salt to balance cell potassium levels as a result of their diet - choices include human perspiration stained boots, tool handles, some paints and glues. But they also chew on non-salty items as a result of their need to hone their two front teeth. The porcupine belongs to the Order Rodentia, and with all rodents, including the beaver, their large front gnawing teeth continue to grow as long as they live. Porcupines themselves have an estimated life span of 5-6 years in the wild, 10-20 years in captivity. If they survive to full maturity they will attain weights varying from 10 to 40 pounds.

The specie of porcupine we know here in Teton Valley has the northernmost range of all the world's porcupines, adapting itself to our harsh winter conditions with considerable success. Its Latin name, erethizon dorsatum translates as "irritable back." Evidence indicates that they immigrated north from South America 3 million years ago - fossils have been found back to the Oligocene period. It has been here a long time. The porcupine is a gentle creature with great, if simple, joy in life. Perhaps, in the spirit of understanding, human society can afford a few girdled trees and exercise a little caution when venturing out with domestic dogs. And if on a hot summer evening you hear the sound of noisy, sucking chewing with uninhibited delight - it's likely there's a smallish brownish being with orange teeth and bright button eyes nearby.