For porcupines, the best offense is a deadly defense.
(Illustration by Delphine Lee)
When you’re a skunk, you know your story will always lead with the stink. When you’re a snapping turtle, it’s going to be the snap. And when you’re a porcupine? Well obviously, it’s all about the quill. Armed with some 30,000 of them, the porcupine is a weapons-grade rodent, an ambling arsenal of needlepoint reasons to be left alone.
The second-largest rodent in North America after the beaver, a porcupine stripped of its quills is just a large, slow-moving, nearsighted, woodland-dwelling plant-eater—hardly a fearsome foe. But those quills make all the difference. Dastardly marvels of natural design, they are modified hairs, hollow and about 2 to 3 inches long, and soft at birth but hardening within a few hours into baby’s little bioweapons.
The business end of the quill is sharper than a hypodermic needle and girdled with hundreds of microscopic barbs; Harvard bioengineers studying porcupine quills found that the barbs make it easier for quills to penetrate flesh, but also make them difficult to remove, flaring out to create resistance when a quill is pulled. And once a quill is lodged in a victim’s flesh, those barbs also allow it to work progressively deeper into the body, at the rate of about a millimeter an hour. Not merely painful, the quills can be deadly, penetrating vital organs and even entering the brain. A Canadian wildlife blog reported on the autopsy of a bobcat that found the cause of death to be massive blood loss, the result of two porcupine quills piercing the vena cava, a major vein that carries blood to the heart.
Porcupines enjoy, if not quite impunity from predation, then certainly considerable wary respect from potential predators.
Contrary to a popular myth, however, porcupines can’t actually “shoot” their quills. Rather, the quills are loosely attached and easily dislodged by even a light brush. The porcupine’s tail is particularly well-quilled, and, when threatened, a porcupine will turn its back and lash that tail at a predator to deliver a payload of pain. “They have a lot of quills, so they can lose a lot and still have plenty left,” says Mike Fies, a wildlife research biologist with the Virginia Department of Wildlife Resources. The quills also regrow within a matter of weeks.
Thus armed, porcupines enjoy, if not quite impunity from predation, then certainly considerable wary respect from potential predators. But nature always appends an asterisk, and in the porcupine’s case, that comes in the shape of a small, aggressive carnivore in the weasel family, the fisher. Fishers specifically target porcupines by patiently and repeatedly attacking from the front, biting the porcupine’s face until the fisher can successfully wear down its prickly quarry and flip the hapless porcupine to expose its unprotected belly.
Fishers aside, the main causes of mortality for porcupines, says Fies, are being hit by cars, killed by humans, or—despite the fact that porcupines are good climbers—falling from trees. Yet although they have a very low reproduction rate, with a female porcupine giving birth only to a single “porcupette” after
a lengthy gestation period of more than 200 days, porcupines seem to be soldiering on. Preferring a habitat of coniferous and mixed forests, in North America they occupy a range that includes much of Canada, Alaska, a large swath of the western US, and from New England south along the Appalachian corridor into Pennsylvania, with patchier numbers in Maryland and West Virginia.
But are there porcupines in Virginia?
Although the Virginia Department of Wildlife Resources lists them as “no longer present in Virginia,” Fies and Dr. Nancy Moncrief, curator of mammalogy for the Virginia Museum of Natural History in Martinsville, have co-authored a paper, published last spring in the Northeastern Naturalist, presenting evidence that at least a few visitors have been wandering our way. In recent years, camera traps and the occasional photo of a quilled dog have hinted that porcupines might be found in western Virginia. But, Moncrief says, “Mike and I share the opinion that the gold standard evidence of an animal’s existence is a dead specimen.”
And so in time came the call to gladden the heart of a curator of mammalogy: “I finally got a road-killed porcupine,” announced Fies.
More followed—perhaps literally. Fies says that at least a few may have hitched rides on logging trucks traveling I-81; as evidence, a live porcupine was found under a car at a highway rest-stop. Others, their research suggests, are likely making their way in from expanding populations in western Maryland and West Virginia.
Moncrief says that nevertheless, we probably can’t call porcupines our own yet. “I think mostly they are one-offs in the state,” she says. “But I wouldn’t be surprised if they become a self-sustaining population in the next 20 years or so.”
This article originally appeared in the August 2021 issue.
