Mad about Science: Porcupines

By Brenden Bobby
Reader Columnist

I’ve lived in this area for my entire life and I have never seen a porcupine outside of a zoo. Perhaps I’m lucky, in that I’ve never had to endure the bitter sting of a porcupine’s quill. However, I’m an animal person, and I love to see the wonder of nature in all its splendor, so it has made me a little sad that I’ve never seen one of these odd creatures in its natural habitat.

Porcupines are the third-largest rodent in the world, just behind the capybara and the beaver. Being rodents, their behaviors mimic many of their smaller kin, like squirrels. Porcupines will stand upright and eat with their forepaws like squirrels and rats. Their diet includes a wide range of vegetation like nuts and berries during the spring and summer, but they will devour the inner bark of trees during winter while resources are scarce. This is detrimental to many tree types and can lead to the death of the tree, particularly in fragile orchards, where they can be the bane of orchardists around the world.

The most recognized feature of the porcupine is certainly its quills. Humans spotting porcupines may be rare, but it’s not uncommon for dogs to discover them through a keen sense of smell and discover for themselves that the third-largest rodent is not to be trifled with. Their quills are modified hairs formed from keratin. Keratin is a protein that exists naturally in the hair, skin, organs and scar tissue of most mammals, though it has been adapted by evolution to provide a more potent sting, in the case of the porcupine.

Keratin is insoluble in water and resistant to many chemicals, giving it protective qualities from rain and other environmental factors. Its rigidity and structural strength is what forms the foundation for the syringe-like hairs that coat the animal.

The nature of porcupine quills means mating is a tricky affair. Porcupines need to make more porcupines after all, so one is inevitably left to wonder: how does this occur when one is covered in a series of spikes?

Porcupines have a mating ritual to signal their readiness for making and raising porcupettes, that is, baby porcupines. The female will often climb a tree and call out to male porcupines, attracting them to her. The strangest part to humans is that the female porcupine will then urinate on the male she has selected to signal to him that she is ready to mate. The female will then use her own tail to cover the spines along her back and give the male something to grab onto during the act. 

From that point, copulation is much the same as it is with any other rodent, only with the added pressure of the male not slipping and accidentally skewering himself.

The gestation period for a North American porcupine is astoundingly long at 210 days. This long gestational period is difficult on the mother, but imperative to the porcupette’s survival. Unlike most rodents, porcupettes are born with their eyes open and able to function almost immediately after birth. They are also born soft, with their quills only hardening after they have entered the world. Often, a mother will only give birth to a single porcupette at a time, which is another strange trait for a rodent.

Porcupettes will nurse from their mothers just like most other mammals. The porcupette is reliant on its mother for several months until it is large enough to be independent. Adult porcupines are largely solitary creatures, but they have been observed creating and sharing dens for warmth in the winter.

Sharing a one-bedroom underground apartment with two of your spiky neighbors seems like a miserable prospect — especially if you’re paying Sandpoint rent prices.

There are two evolutionarily distinct groups of porcupine in the world: Old World porcupines found primarily in Europe and Asia, and New World porcupines found throughout the Americas. They are surprisingly not very closely related, having shared a common ancestor roughly 35.4 million years ago. North American porcupines tend to occupy forests and grasslands, even claiming the upper limbs of trees as homes from time to time, while many Old World porcupines will prefer rockier environments. The quills of the two groups and the subspecies within these groups may vary wildly in size, shape and composition.

Porcupines have been the subject of human research, particularly in the study of their quills. The quills are rigid but flexible and extremely sharp. Some have specialized barbs that make removal extremely difficult and painful, something that has been studied for both weaponization as well as medicine. Their quills have been studied to develop more effective syringes and needles, which is a bit of a horrifying prospect.

Porcupines are a dietary staple in southeast Asia. The Malaysian porcupine has suffered population decline due to its use in cuisine. The North American porcupine has been described as malodorous and not fit for human consumption. To be fair, most North American rodents aren’t very appealing to eat.

Stay curious, 7B.

Today’s topic was suggested by Molly. Thanks, Molly!