Porcupine - Erethizon dorsatum

Most visitors to Wind Cave have the opportunity to observe and enjoy a variety of wildlife that live in the park such as the bison and mule deer. For some visitors, a trip to Wind Cave may include a rare encounter with one of the more elusive park animals - the porcupine. Usually seen at night near roadsides or in trees, the porcupine may appear to be a large raccoon. In reality, this furry climber is a rodent and is second only in size to the beaver.

When it comes to defending itself, the porcupine is in a league of its own. The porcupine is covered with 15 to 30 thousand specially adapted needlelike hairs called quills. When in danger, the quills rise to the occasion, just as a cat's hair stands on end, resulting in an almost impenetrable shield of pins. A common myth about the porcupine, is that it has the ability to shoot their quills. In reality, the quills are controlled by muscles and are released instantly when they come into contact with another object.

Porcupine covered with quills
Porcupine covered with quills

NPS Photo by Randall Williams

Another common myth about porcupine quills are that they are barbed like fishhooks. In reality, the ends of the quills have diminuative, overlapping scales which make the quills act as though they are barbed. Because of the configuration of the scales, the quills will move forward once embedded.This will cause the quills to become deeply embedded. The quills may move through the skin, up to a millimeter an hour!

There was once a porcupine researcher that studied the way in which quills moved through the skin. He found out the hard way. A quill was driven so deep into his arm, that he had to let it go. The quill moved all the way through his arm and came out the other side! Although he suffered great pain, there was no infection. A closer examination of the quill revealed that the quills contain an anti-biotic. The porcupine, in this way, has an insurance policy against its own defense!

The porcupines range extends from the tundra of Alaska to the deserts of New Mexico. It is found throughout most U.S. and Canadian forests with exception of the southeastern and prairie states. Porcupines prefer forested habitats. They den under or inside of dead logs, and in shallow caves.

Imagine giving birth to an animal with 15 thousand quills! Baby porcupines, or "porcupettes" are born in the spring, and lucky for mom, the quills are soft at birth. After a few minutes in the outside air, the quills harden and are ready for defense. Within an hour, the porcupettes will be able to climb trees.

In the spring and summer porcupines enjoy a diet of vegetation including shrubs, grasses, and fruits. During the winter, when fresh greens are not available, the porcupine survives by eating the cambium, or inner bark of trees. The porcupine has an iron coating on its teeth to help it scrape away the outer bark. In addition to this adaptation, seventy-five percent of the porcupines body is devoted to digestion.

Last updated: January 18, 2018

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