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Nature Notes: Porcupine

Ed Robinson
September 6, 2022

An old French name for this creature is “porc d’espine,” literally the “pig with quills.” But you will not find roast porcupine gracing the table in a three-star Michelin restaurant. There are, however, many recipes online for a dish called “porcupine meatballs” which fortunately substitute long grain rice for actual quills. Unless you are lost in the woods and starving, I suggest you give the porcupine a wide berth, especially if your dog is unleashed.

Porcupine on log

Porcupine, photo by Moose Henderson, iStock.

The porcupine is not a hog but a rodent, the second largest in North America after the beaver. Spend enough time afield and you will find a porcupine waddling along or clinging to a tree. This animal is not built for speed but they are built for climbing trees—some of the world’s 24 porcupine species spend their entire lives aloft. That may not be all bad since their lumbering gait often results in porcupines ending up as roadkill. Before continental drift occurred 30 million years ago the porcupine’s ancestors crossed from Africa into South America and began spreading north across the Isthmus of Panama. I suspect they needed at least 20 million years to waddle on up to Maine!

Our local porcupines are part of the North American species Erethizon dorsatum, with seven recognized subspecies. The animal native to Maine is labeled E. dorsatum dorsatum, ranging from Nova Scotia to Alberta and from the Yukon to Virginia. They live in forested areas with thick conifers being the prime hangout. Porcupines are vegetarians, favoring green plants, twigs, fruit, nuts, clover and skunk cabbage. Most feeding takes place at night.

Porcupines have a thick layer of fur but it is covered by a mass of quills from head tail, as many as 30,000. At birth the quills are soft but they harden within hours. The quills are needle sharp with hundreds of overlapping, backward-facing barbs that make removal difficult. A face full of quills and the infections that often follow have caused many predators to regret their attack on a porcupine. The four-inch quills are a type of hair, covered with keratin for durability. Ranging from black to tan the quills are hollow, allowing the porcupine to swim with ease. Despite old myths, the porcupine cannot “throw” his quills when disturbed, rather the quills release upon contact with an object or animal. New quills quickly develop as replacements.

At maturity porcupines weigh 15–40 pounds and may reach three feet in length not counting the tail. Their feet have soft soles for a good sense of touch and long claws for climbing trees. Aloft, the porcupine can stay in place with just the hind feet, using the front feet for feeding. It is not uncommon for porcupines to reach just a little too far for some tender food item resulting in a fall to the ground. Their skin has built-in antibiotics to help the animal recover from injuries or self-inflicted quills.

What creature would be crazy enough to attack a porcupine? Porcupines are generally passive creatures and their self-defense is heavily dependent upon their quills. When threatened the porcupine clacks its sharp teeth, exudes a strong odor from a special scent gland on its back and swings its tail toward the predator. There are documented cases of many predators carrying quills including coyotes, bobcats, wolves, wolverines, bears, and large birds of prey. Most of these attacks seem to involve young animals unaware of the danger or older animals in dire need of food. Only two predators are known to be skilled at taking a porcupine, fishers and cougars. The technique used is to repeatedly bite the porcupine on the snout, sometimes shaking and dragging it until it expires, then flipping the porcupine over to expose the unprotected stomach.

Mating takes place in the autumn and requires some careful maneuvering. Males are quite vocal while seeking a mate and will fight for dominance. During copulation the animals tighten their skin so the quills lay flat, avoiding injury. After mating the male may defend the female from other suitors, probably an evolutionary adaptation intended to ensure the dominant male’s sperm fertilizes the egg. But then the male is off in search of another willing female. Seven months later a single baby is born, known as a porcupette, and the female will care for her offspring for several months. While captive porcupines have lived to the ripe old age of 25, in the wild the average is probably more like ten years.

If you live near porcupine habitat and take a dog for forest walks, be sure to keep your pet away from a porcupine. Dogs seem wired to charge after the slow-moving animals, perhaps because the porcupine has a strong odor. But the dog is almost always the loser in such encounters. Worse, dogs have short memories—a veterinarian reported pulling quills from a patient 15 times! Please note that vets strongly advise against trying to pull quills from your dog at home; you may injure the dog and receive a serious bite for your efforts.

Outside of their mating season porcupines live alone, the exception being shared winter dens such as hollow logs, small caves or tree cavities. The animals do not hibernate but sleep through cold snaps while remaining active in mild weather eating conifer needles and tree bark. That feeding can do considerable damage in a stand of trees but serves to allow insects to enter the trees, to be followed by foraging birds. Like the moose, the porcupine is particularly attracted to salt and wins few fans when he decides to chew on salt-flavored hiking boots, canoe paddles, plywood siding or truck tires!

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