Have you seen one of these in Sonoma County lately?


Hint: this is a North American porcupine (Erethizon dorsatum).

If your answer is “no”, you aren’t alone.

In California, they are being seen less and less. At least according to a 2012 article in the Sacrameto Bee, “Pocrupines an increasingly rare sight in California forests, scientists say” This article refers primarily to the Sierras and California’s northwest corner however, and the status of porcupines here in Sonoma County remains mostly a mystery.

The natural range of this porcupine species stretches from Alaska through most of Canada, down into the northeastern U.S. and in parts of the western U.S. all the way to Mexico (see IUCN’s range map here -you’ll notice Sonoma County isn’t included but our neighbors Mendocino and Lake Counties are). In California, their range isn’t well known.

Dr Rick Sweitzer of UC Berkeley, in a presentation available online offers that porcupines weren’t even seen in northern California (Del Norte and Humbolt Counties) until after 1900, and it may be that logging of virgin Douglas fir and Redwood forests created habitat they preferred and contributed to their expansion.

Here in Sonoma County, Pepperwood Preserve caught one on a wildlife camera in their 2011-2013 surveys, and Sonoma Land Trust got a picture of one moving through the Sonoma Valley Wildlife Corridor in the fall of 2014, which once again shows the importance of this corridor for local wildlife.

If they truly are in decline, porcupine breeding habits likely won’t help them rebound quickly. Although they are a rodent, and most rodent’s have a reputation of reproducing with fervor, North American porcupines have only one baby at a time, called a “porcupette” or “kit.” After a gestational period of 202 days, the mother porcupine nurses the kit for four months.

1_Julie Larsen Maher_1923_North American Porcupines and Porcupette_CZ_BZ_08 10 15
Porcupine and porcupette, photo from WCS Newsroom

They have a long life expectancy, and some have lived up to 30 years old. They are also great at climbing trees – but, are a little less great staying in them. For example, author Craig Child’s described his experience climbing a tree in strong winds to get a better look at a porcupine in a nearby tree, “Now the animal is lying there, perfectly cupped in a crotch of branches. Its right foreleg hangs lazily and drifts in tandem with the tree,” but them reminds us, “Don’t be misled by their casual manner of hanging from trees overhead. They are no daredevils. Porcupines do fall.”

Indeed, scientists found evidence that they may fall frequently enough to have affected the evolution of their quills: porcupine quills contain antibiotic properties and researchers believe this may be because porcupines often quill themselves during accidents like falling from trees.

from sciencemag.org (http://www.sciencemag.org/news/2012/12/porcupine-quills-reveal-their-prickly-secrets)
The barbed end of a porcupine quill, photo from sciencemag.org.

Falling from trees may hurt, but it isn’t the main reason for porcupine deaths. Mountain lions and fishers like to munch on them and are the most effective predators. But other, less natural causes are also a problem, such as accidentally getting hit by cars or being targeted directly. Porcupines like to eat the inner bark of trees, and so strip the outer bark away. While this doesn’t kill the tree, it can cause it to grow in a misshapen way. Because of this bark-eating propensity, there are records of widespread poisoning and shooting of porcupines from the US Department of Agriculture and the Forest Service from the early 1900s to 1977. While these agencies don’t target porcupines anymore, they still place some rodenticides out to protect seedlings. According to that Sacramento Bee article, more concerted efforts of poisoning porcupines may still be coming from private logging companies and marijuana plantations concerned for their irrigation tubing (which porcupines like to chew on).

iNaturalist is a great way to help solve the mystery of porcupine populations in Sonoma County. As of today, there are two sightings listed online – in Austin Creek State Recreation Area in 2011 and another in 2015 in west county.

So help out land managers and porcupine researchers: if you see a porcupine waddling around or climbing a tree, be sure to let someone know! You can contact Sonoma Land Trust, and/or post it to inaturalist.

Just remember not to touch the porcupine and it’s ~30,000 quills. While it’s not possible for them to shoot out as some porcupine lore suggests, if touched, the quills can be quite difficult to remove (so get help if you get quilled and can’t get them out). Each quill has microscopic barbs which help it to keep going forward and prevent it from backing out. These fascinating weapons keep working their way through flesh until they either pop out the other side or hit an important organ and kill the predator foolish enough to mess with the spiky porcupine.

Where have the porcupines gone? Or are they newcomers?