The North American porcupine has a few tricks up its quills

Sporting one of the most recognizable hairdos around the Chesapeake Bay watershed, the North American porcupine (Erethizon dorsatum) is the second-largest rodent in North America, behind only the beaver. It can be found waddling along on the forest floor, paddling down a slow-moving stream or scaling the towering trunk of a sugar maple.

The porcupine’s most iconic feature is its quills: sharp, stiff hairs with hundreds of tiny barbs located at the tip. While porcupines cannot throw their quills, they detach easily and can lodge themselves into the skin of predators, where the barbs make them difficult to remove. An adult North American porcupine has around 30,000 quills.

North American porcupines are talented climbers and spend much of their time in the tops of trees, where they munch on bark and sometimes build nests. However, they are not always graceful. Of the 16 species of tree porcupines, the North American porcupine is the only species that lacks a prehensile tail, which is designed to hold and grab onto branches. Without the help of this specialized tail, the North American porcupine will occasionally lose its balance and tumble out from the tops of trees. Upon impact with the ground, the porcupine will often impale itself in an unfortunate process known as “self-quilling.”

The good news is that the North American porcupine has an adaption to accommodate these occasional accidents. It has evolved to produce a topical antibiotic on its quills, which acts like penicillin. The thin, greasy coating on the quills prevents the growth of bacteria and minimizes the risk of infection, should the porcupine ever prick itself.

In some areas, porcupines are considered a nuisance. They have intense salt-cravings and are known to gnaw on human-made structures such as sheds, outdoor furniture and even automobiles in search of sodium. The Chesapeake Bay Riparian Handbook also notes that porcupines pose a threat to riparian forest buffers: streamside trees and shrubs that prevent pollution from entering waterways. Porcupines may chew through recently planted trees in search of food or building materials, devastating riparian areas.

Their disruptive behavior is likely due to the loss of the porcupine’s favorite snack-tree, the eastern hemlock. In recent years, the hemlock has been under attack by the hemlock woolly adelgid, a tiny, invasive insect that is killing off the region’s hemlock population. Preserving the porcupine’s habitat is crucial to ensuring that these well-meaning creatures stay out of trouble.

Porcupines are shy, unaggressive creatures and will not harm you as long as you keep a respectful distance. Learn more about the North American porcupine in our Field Guide.