November 18, 2018 was a windy day in Helena, Montana. At the Sevenmile Creek restoration site, the Russian-olive (Elaeagnus angustifolia) branches danced in the breeze, dangling their mealy fruits and waving withered white leaves. And there, clambering slowly among the branches, was a porcupine (Erethizon dorsatum). Its blond guard hairs quivered as it scraped a meal of inner bark from the tree.
Two weeks later, I saw it again. Cold weather had frozen most of the stream. A small patch of open water remained, burbling frigidly past before disappearing again under the ice. And nearby, on a shelf of ice, was the porcupine.
It was entirely unaware of my presence on the bank above it. Head down, it seemed to be finding something to eat on the thick ledge of ice. I descended the bank towards it and the porcupine remained unconcerned, ignoring me as I approached within yards.
I set my backpack down, pulled out my camera, and began filming. The porcupine looked comical, head down and out of sight, a soft-looking lump of brown surrounded by an aura of long, tawny guard hairs. I watched as it waddled awkwardly towards an alder sapling near the water, its head still obscured behind its body. What was it doing?
A porcupine and a ledge of ice
The porcupine clambered slowly over the alder branches, each comical waddle of a step thoroughly considered. It sniffed at a dormant gray alder twig but rejected it. It stopped briefly where a blanket of snow covered a downed log and began consuming snow crystals, vacuuming them up delicately. Apparently, with the open water of the stream difficult to access safely, frozen water was the day’s beverage of choice.
Eventually, the porcupine’s methodical pace brought it to the far side of the alder. There, at the very edge of the icy shelf, I watched the creature bend its head down to chew something. Once again, I couldn’t quite see what it was eating. Nose quivering, head craned, the porcupine focused its attention on the icy edge.
What was happening? I inched slightly closer. From this angle, I could see that it was gnawing at the ice. Its enameled incisors made a surprisingly loud, rough crunching as it rasped ice from the ledge. Once again, I could only assume that it was making do with frozen water while liquid water was hard to access. But how could I know what the porcupine was actually experiencing? Perhaps it was enjoying the ice-gnawing. Could this be the porcupine equivalent of the frozen dessert section in the grocery store?
Bumping into a porcupine
The problem with getting up close and personal with an utterly oblivious, docile, spiny rodent is when that rodent gets surprised. During the ice-rasping session, the porcupine had remained several yards away from me, on the other side of the alder sapling. And as I would soon be able to confirm, it had remained completely unaware of my presence. But then, evidently done with its icy meal, it began clambering towards me.
Its movements were slow and laughably awkward. But nevertheless, the porcupine didn’t have far to go. And it still had no clue I was sitting on the steep streambank at the edge of the ice, a bit too well-settled for a quick getaway. I was directly in the porcupine’s path.
This was not a situation I had prepared myself for. The porcupine was now less than a yard away. As much as I might have enjoyed telling people that I had bumped into a porcupine – literally – I didn’t relish the thought of the potentially prickly aftermath. I began talking to the now far-too-close rodent in a low, calm voice.
Immediately, its behavior changed completely. The porcupine made some low humming noises and inflated itself, puffing out its guard hairs and its short but painful quills. Turning its back to me, its defensive spines flared out, it made a lumbering retreat, plodding across the ice to the far side of the stream. Phew, disaster averted.
Escape into the branches
I apologized to the porcupine for disturbing it. It rested there briefly, a bristly ball twice the size it had been before. Its guard hairs remained fanned out around its body like an imposing, three-dimensional turkey tail.
Gradually, it recovered from the surprise, laying down its quills and hairs. But still, my unexpected presence was not to be ignored.
In spite of its awkward gait, the porcupine was a skilled climber. Just minutes after its pause at the edge of the ice, I watched it methodically ascend a small Russian-olive across the stream, escaping into the canopy. Its thick, rubbery foot pads and stout claws helped it move expertly from one branch to the next. When I left it in peace a few minutes later, it had found a perch midway up the Russian-olive. It remained there as I walked away, twitching its nose and soaking up the afternoon sunshine.
Denning and feeding
I saw the porcupine several more times during that winter. Near a rarely-used access road, there was an old metal culvert that lay buried. Dry now, in previous years it had carried irrigation water under the road. For the porcupine, the culvert had become a well-protected spot for a winter den. I found it there on several occasions. Sometimes it would rest just inside the entrance. Once I found it far back in the depths, a bulky tan shape reflecting the glow of my flashlight. The bottom of the culvert was a thick carpet of porcupine scat. Evidently this individual, or another, had been here in past winters, too.
On other days, I saw the porcupine in the Russian-olives, stripping inner bark with its deep orange incisors. I watched it feeding on the Russian-olive fruits, too, using its surprisingly nimble front paws like hands to bring the fruits to its mouth.
At one point, it tested its luck, inching ever-higher on a slender Russian-olive branch. I watched the branch bend farther and farther until the porcupine was hanging upside down, clinging to it with all fours, still feeding intently on the fruits. Finally, the branch gave way with a crack, sending the rodent tumbling. But once again, the porcupine proved surprisingly quick to react, catching itself on a lower limb as it fell.
By March, the porcupine had disappeared from the area. Throughout the spring and summer, I saw no sign of it. But the next winter it was back, sheltering in the culvert again. At least I suspected it was the same individual, since it was using the same culvert for a den.
Around Helena, I still hear other naturalists mentioning porcupine sightings from time to time. But farther west in Montana, porcupines have disappeared almost entirely. A 2015 article by Ellen Horowitz in Montana Outdoors describes their puzzling decline in the conifer forests west of the Continental Divide. Once common in those forests, porcupines have become exceedingly rare there since the 1980s. And no one knows exactly why.
I spoke with Jessy Coltrane, a wildlife biologist with Montana Fish, Wildlife and Parks, to get an update on western Montana’s porcupines.
“If you see a porcupine, it’s like finding a unicorn,” she told me.
Porcupines remain very rare west of the Continental Divide. When they are seen, it’s most common to find them in low-elevation deciduous habitats near water. Jessy told me that there have been a handful of recent sightings in higher-elevation conifer forests – which is hopeful. But these extremely rare sightings are a far cry from the 1960s. Then, porcupines were abundant enough that U.S. Forest Service employees managed to shoot 30 or 40 of them in a single weekend, considering them a threat to timber trees.
Few births, many ways to die
Although porcupines do feed on tree bark during the winter, in reality these slow-moving rodents do little damage to forests. But humans have done much damage to porcupines over the years. These animals are long-lived and reproduce slowly. Females give birth to, at most, a single baby each year. Pregnancy puts a strain on their fat reserves. With the stress of our harsh winters, it may take two years for a female to build up enough fat to give birth again. Porcupines reproduce just about as slowly as grizzly bears, Jessy tells me.
And in spite of their protective spines, there are many ways a porcupine can die. Winter is a severe test for rodents that subsist on low-calorie bark and twigs. Some people still shoot porcupines for fun. Others are lost to roadkills. And a few predators – namely, mountain lions and fishers – are skilled at hunting them.
The days of killing porcupines with poisoned salt blocks, laced with strychnine, are gone now, at least on federal lands. (This practice ended in the 1970s.) But nevertheless, recovery is an uphill battle for an animal that reproduces as slowly as a grizzly and still has no legal protection in Montana.
At Sevenmile Creek, too, porcupines have disappeared. In September of 2020, a wildfire swept through the area, burning most of the shrubs on the restoration site. The shrubs have recovered fast, the majority of them resprouting from their root systems. But nevertheless, winter bark and cover is relatively scarce now. Porcupine habitat has become marginal. Since the fire, I’ve seen no sign of porcupines in the area.
Have you seen any porcupines recently? Getting to know this one – watching it gnaw ice, pick Russian-olive fruits, and perform acrobatics in the branches – has given me a deep appreciation for these placid rodents. And knowing that they seem to be in trouble makes every encounter with them even more special.
As the shrubs at Sevenmile Creek grow back over the years ahead, I’ll be watching for the telltale marks of incisors on branches that tell of winter feeding. I’ll be checking the culvert where years of porcupine scat have accumulated, shining my flashlight into it and hoping to find a bulky rodent. And one of these years, with luck, a porcupine will return.
Horowitz, E. (2015). Where have all the porcupines gone? Montana Outdoors, March/April 2015. Retrieved from https://issuu.com/montanaoutdoors/docs/porcupines
Mally, K.A. (2008). Hierarchical summer habitat selection by the North American porcupine in western Montana. M.S. Thesis, University of Montana. Retrieved from https://scholarworks.umt.edu/cgi/viewcontent.cgi?article=1534&context=etd
Neitro, W.A. (1970). A permanent type poison station for porcupine control. Proceedings of the 4th Vertebrate Pest Conference. Retrieved from https://core.ac.uk/download/pdf/188055102.pdf