It’s not easy being a porcupine

  • If you have traveled anywhere in the last month, you have likely seen numerous dead porcupines in or along the edges of roads. This is the time of year, when the young leave their mothers and head out on their own into uncharted territories, often crossing roads. AP file

  • An ambassador porcupine from the Squam Lakes Natural Science Center chomps on some leaves at New Hampshire Audubon in Concord. Monitor file

  • A porcupine steps out onto a frozen pool of water near Herbert Glacier on Friday, Nov. 27, 2015, at Juneau, Alaska. (AP Photo/Becky Bohrer) Becky Bohrer

For the Monitor
Published: 10/9/2019 3:30:49 PM

A recent article in these pages mentioned a fungus that is impacting porcupines. But that’s not the only thing that these large rodents are dealing with.

If you have traveled anywhere in the last month, you have likely seen numerous dead porcupines in or along the edges of roads. This is the time of year, when the young leave their mothers and head out on their own into uncharted territories, often crossing roads. The porcupine, being slow, near-sighted and usually out at night, is at a distinct disadvantage when encountering speeding vehicles.

Though the porcupine doesn’t have defense mechanisms to deal with cars, it has amazing adaptations for survival against its natural predators.

Its quills, the most obvious protection, are worth examining, at least from a distance. Quills are a type of modified hair, varying in length from a ½-inch to 3 inches. Each of the 30,000 quills on a porcupine is equipped with microscopic barbs that help the quills stick into a predator. Once embedded in the skin of an aggressor, the barbs help the quill penetrate deeper into the skin. With every muscle contraction of the animal the barbs inch their way further in. Sometimes these miniature arrows reach a vital organ and cause death to the attacker. The smallest of the quills are most likely to do this and thus are considered the most dangerous.

While they can be menacing weapons, the quills cannot be thrown by the porcupine. When a porcupine shakes, the quills may come loose and fly off, just as the hair of a dog will scatter when it shakes, but there is no active or purposeful projectile ability. New quills grow to replace those that are lost. The largest quills are on the back and tail. These are displayed to a predator if one gets too close, presenting a formidable shield of protection.

A porcupine’s face and part of its belly are quill-free and thus vulnerable. The porcupine’s prime predator, a large weasel called the fisher (often called the fisher cat), takes advantage of that. A fisher will rapidly circle a porcupine, prompting it to continuously turn to try to keep its back toward the fisher. Eventually the fisher out paces its prey and is able to attack the porcupine’s face. Once killed, the fisher flips the spikey creature onto its back, exposing the un-quilled belly. After it eats, only the skin and quills remain. This meal will provide enough nourishment to fortify the fisher for up to a month.

Tree climbing helps porcupines avoid predators such as foxes and coyotes. Long claws and textured foot pads provide grip and friction as they scale up the trunk of a tree. Short, stiff, bristle-like hairs on the underside of their tail act as a break, keeping them from slipping backwards as they ascend a tree.

Another reason that porcupines climb trees is to access food. Though strictly herbivorous, their diet varies by season. Their diet shifts from ground vegetation in the summer to buds, branch tips, nuts and inner bark of trees in winter. They will feed on maples, aspen, apples, red oak, beech or spruce, but Eastern Hemlock is a favorite. Since the tips of branches are too flimsy to support their weight, the porcupine will chew off a branch closer to the trunk, then nibble the tender tips, letting the rest of the branch fall to the ground. Finding a hemlock with small branches scattered about on the ground is a sure sign that a porcupine has been feeding in the canopy above.

If you find such a place, look up. You might locate a dark blob resting against the trunk where it could spend several days. As winter approaches though, it is more likely for porcupines to retreat to a den in a rocky ledge, a hollow log or tree or even under a building. These hideouts are easily recognized because the inhabitant urinates and deposits scat (which look like brown elbow macaroni) at the entrance of the den. You will likely smell it before you see it.

You might also hear a porcupine before you see it. Their vocalizations occasionally include screams but mostly consist of low grunts, moans and mutters. Hearing the porcupine talking to itself is by far the most entertaining way to encounter this wild neighbor.




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