The seldom-seen North American Porcupine stays to endure winter on the prairie. Photo by Reserve Maintenance Specialist Scott Heidebrink
Most rodents either hibernate or burrow during the frigid months, but the porcupine enlists a different strategy, choosing to spend its time atop a tree. Surprising, given the cold temperatures and brutal winds that they must confront, but the porcupine is well equipped. Their strong, curved claws make perfect climbing tools, and the coarse texture of their soles help them grip the branches. Staying in a tree safeguards them from predators like the occasional coyote or mountain lion who dares engage the porcupine and its quills.
But to stay in the tree, the porcupine must be able to endure harsh winter conditions and find food. In addition to their infamous sharp spines, the porcupine develops a thick winter coat comprised of two layers. The first layer, or underfur, is comprised of a thick growth of thin, crimped strands, which provides great air-trapping capability. The longer guard hairs provide most of the dominant color of their coat, and in winter, these grow in length and number providing additional insulation. While the summer coat of a porcupine keeps them comfortable on cool nights, down to about 45° F (7° C), their winter coat helps them maintain a normal body temperature in weather as cold as 10° F (-12° C) (Marchand, 4th ed. p. 101). Below that, the porcupine must seek external sources of heat (sunshine) and metabolize extra food, which in their case is the inner bark of the tree they inhabit – their teeth and intestinal flora are both adapted to consume woody material.
Porcupine will sometimes take shelter in a den, usually in the crevices of nearby rocks and hollow trees. But when ground cover is scarce, they allocate most of their time in the safety of a tree.
Many animals on the northern prairie lose a tremendous amount of lean body mass during winter due to accelerated metabolic rate and lack of food, but the porcupine typically does not suffer such a fate. The porcupine is not only a true survivor but is well adapted to the challenges that nature offers. This animal is a part of an exclusive club of individuals that stays and endures, or “hunkers down,” during the prairie winter.