Porcupines are unique, quilled rodents, and winter is a great time to view them, because they are relatively easy to find. During the summer, a porcupine feeds on leafy plants, and is well disguised as a clump of grass. However, during the winter, their food source changes to the bark of conifers, especially on lodgepole pines, and they also browse on the needles of subalpine fir.
Learn to look for porcupine sign; subtle clues that tell you that a porcupine is in the vicinity. For instance, you’re walking beneath some large conifers, and you notice cashew-sized droppings scattered about. Closer examination reveals that the scat consists of tightly packed sawdust-like plant matter. Porcupine scat is generally not in piles of pellets like deer or elk, but is scattered here and there beneath a tree. Logic tells you that there must be a porcupine in the tree somewhere above the scat. Porcupines can stay in the same tree feeding for many days, and even weeks. You can easily pass beneath them, but with some new tools to hone your senses, you may start to see them more frequently.
Look for porcupines on branches, or near the tree’s trunk. They can be at any height in the tree, from eye level, to the very tip-top. Porcupines are about the size of a basketball, and are generally gold and brown in color. They are well-disguised as a clump of pine needles. The gold color is its long guard hairs, which cover most of its body, except for its face. The guard hairs protect the porcupine’s soft insulative fur from wear and tear. The brown color is its dense inner fur, which insulates it from the cold. The cute porcupine face is brown with gentle brown eyes.
If you look all around in the tree, and still can’t find the hidden porcupine, take a closer look at the base of the tree for signs of tracks. The porcupine may have switched trees. Tracks may not be obvious on crusty snow, but porcupine tracks are distinctive in soft snow. Porcupines generally move only short distances, usually less than a hundred yards, and they move in a slow, plodding fashion. Even when they try to move quickly, they are pathetically slow. This slow, rhythmic, walking gate is reflected in its tracks. The path of a porcupine is a swale in the snow, reflecting the width of its body. Its feet are pigeon-toed, and the tracks together form “arrows” which point in the direction of travel.
Other evidence to look for is a pile of 2-4 inch strips of bark, on top of the snow, beneath a tree. The porcupine strips away the outer bark and then discards it, revealing the nutritious inner bark of the tree, known as the cambium layer. The porcupine uses its teeth to carefully gnaw the cambium from the wood on the tree’s trunk, or on larger branches. You can tell the freshest chew marks on trees, because they are whitish in color. Older chew marks appear golden, as a result of the tree producing sap to cover over the wound.
When you see a porcupine in a tree, you may not be able to see its quills. The 30,000 quills stand up only when the porcupine is frightened, much like our human hair stands on end when we’re frightened. The needle-like quills of a porcupine are in fact modified hairs. Contrary to popular belief, porcupines cannot “shoot” their quills. However, with barbed tips, the quills do release, and penetrate, with the slightest touch. Inflicted animals find them nearly impossible to remove, and very painful. Interestingly, when threatened, porcupines will swim readily, and the air filled quills act like a life-vest, providing buoyancy, which helps keep the porcupine afloat.
In Eagle County, the porcupine’s predators include coyotes and mountain lions. These predators get their paws underneath the porcupine, and flip it over to get to its exposed underbelly, where there are no quills. I also once came upon the remains of a porcupine that was evidently killed, and eaten, by a hungry black bear, one April day.
Porcupines are good-natured animals, and can often live 5-10 years in the wild. If you get the chance to see a porcupine up close, or through binoculars, I think you’ll agree it is a fascinating animal. Porcupines add to the rich diversity in the animal life by which we are surrounded, in our fantastic home, Eagle County.
Tom and Tanya Wiesen are owners of Trailwise Guides; a year-round Vail Valley guide service specializing in hiking, mountain biking, and natural history tours. Daily private tours are available. Contact Trailwise Guides at (970) 827-5363.