Mountain Lions Versus Porcupines

F99, an orphaned cougar kitten, caching an elk carcass she discovered. Photograph by Mark Elbroch / Panthera

What did F99, a subadult female mountain lion followed by Panthera’s Teton Cougar Project, think when she encountered a North American porcupine in early November? A small, female mountain lion in the Northern Rocky Mountains might weigh 80 lbs, while a large porcupine might weigh 20. Certainly, the two species aren’t matched for a fair fight—mountain lions are stealthy predators that make their living by killing and consuming animals, and porcupines are waddling prey that make their living by chewing bulbs, fungi, foliage and inner bark. Yet, somehow, porcupines sometimes win.

And F99 was an especially small mountain lion, weighing just 40 lbs. She was stunted from malnutrition after being orphaned when her mother was killed on the last day of March, 2014 (see Why Do Adult Cougars Kill Each Other?). Since then, F99 had proven a capable hunter of diverse small prey (see Fumbling Cougar Kittens: Learning to Hunt), but as far as we knew, she’d never tackled a porcupine—to our knowledge, she’d never even seen a porcupine, as they were rare in her mother’s home range.

Of course we’ll never really know what F99 was thinking when she spotted the porcupine—likely something along the lines of identifying potential prey, but that’s only speculation. What we inferred from investigating the site where she killed the porcupine and from seeing F99 herself, was that she pounced upon her prey, pulled it to her chest, and killed it quickly; she nearly consumed the porcupine in its entirety, hide included. Now one of the fascinating things about porcupines is that they don’t wear armor, like armadillos or pangolins. Instead, they wear weapons. Each porcupine wears about 30,000 quills—specialized, hollow hairs that are rigid and sharp. They cannot shoot their quills, but quills are easily shed. Porcupines have a strange layer of musculature just below their skin responsible for raising and lowering their quills; this musculature can also release quills that come into contact with a predator.

The erect quills of an agitated North American porcupine that felt threatened by the presence of the photographer. Photograph by Mark Elbroch / Panthera
The erect quills of an agitated North American porcupine that felt threatened by the presence of the photographer. Photograph by Mark Elbroch / Panthera

Quills are 0.8 to 4 inches (2–10 cm) long, each tip with 700-800 barbs that make them difficult and painful to remove. The barbs are angled in such a way that if the quills are left unattended, they plunge deeper and deeper into the unlucky victim as it moves. Should the quills avoid large bones and vital organs, they can work their way straight through an animal with enough time and come out the other side several months after the encounter. But if they do puncture vital organs, the porcupine may kill their attacker slowly, even long after the porcupine was killed itself. And although quills are covered with a mildly antibiotic fatty compound that likely reduces the risk of infection where quills puncture skin, organs that are injured internally often become susceptible to bacterial disease that create complications. For instance, lungs punctured by quills may contract pneumonia. (More info about quills can be found here.)

One might expect such prickly prey to be avoided by most predators, but alas they fall victim to fishers, coyotes, bobcats, and mountain lions. Some mountain lions, in fact, seem to be especially fond of porcupines—perhaps they like the taste, perhaps porcupines are just easy prey, but whatever the reason, some cougars clearly seek them out. In fact, mountain lion predation of porcupines can be so intense, that its been speculated that they’ve wiped out local porcupine populations throughout the west. For example, Sweitzer et al. (1997) reported that a small population of 80 porcupines in Nevada was reduced to less than 5 animals in just three years—and that the primary reason was predation by mountain lions.

A North American porcupine waddling along. Photograph by Mark Elbroch / Panthera
A North American porcupine waddling along. Photograph by Mark Elbroch / Panthera

F97, a young female here in the Tetons, dispersed from her mother’s home range and killed 24 porcupines in just 2.5 months before we lost track of her. Two young male mountain lions we followed in western Colorado, dispersed in different directions, one east and the other south. Both took special interest in porcupines. P1 killed 35 porcupines in 3 months and P3 killed 10 in the same time frame. Typically, a porcupine needs only to protect its vulnerable face from attack since its quills defend its body. Cougars, however, sometimes ignore the quills and bat porcupines into submission regardless. Numerous cats we’ve captured over the years have had quills stuck in their forelimbs and sometimes in their cheeks. F97 employed her own method—she climbed trees and threw porcupines to the ground, where the fall would injure or stun them long enough for her to attack their vulnerable bellies.

How I wish I could watch an experienced mountain lion kill a porcupine—long have we debated how they do it. Master porcupine hunters skin them perfectly, leaving behind the porcupine’s entire hide and often the tail and a few feet as well. It is the novice porcupine hunters that are at risk. M34, a 15-month old male mountain lion here in the Tetons, was killed in his first encounter with a porcupine. We found his body curled up at the base of a tree—his underside, chest, neck and one side of his face were completely covered in deeply embedded quills. We don’t even know it he succeeded in killing the porcupine. F99’s story is a slight variation.

F99, stretching near a striped skunk carcass she killed. Photograph by Mark Elbroch / Panthera.

F99 clearly pounced on the porcupine she encountered, but she dispatched it quickly. Over the next month that followed she groomed herself excessively, completely removing the fur from the inside of her front limbs—a sure sign of stress as well as the coverage of embedded quills. Five weeks after she’d killed and consumed the porcupine, we were able to study her condition more closely. She moved with characteristic feline grace and looked completely healthy—we spotted a few quills near one eye, but otherwise she appeared unscathed. But shortly after, we found her dead, laid out in a bed she’d been keeping near an elk carcass she’d discovered and had been scavenging.

A necropsy performed by Dr. Maura Connolly revealed that the porcupine had killed her. Her entire chest cavity was dotted with wounds from migrating quills that entered through her chest—and the quills themselves were evident in her lungs, chest cavity walls, and bloody fibrin (clots that formed where there were internal wounds). One lung had completely failed and consolidated, and the other was wounded significantly.

F99 was nearly 16 months old when she died just before Christmas. She’d survived insurmountable odds since being orphaned in March (also described in Orphaned Cougar Kittens). She survived vicious temperatures last winter that claimed the tips of her tail and ears. She and her sister had survived without a mother by scavenging winter-killed elk and old wolf kills. She survived being alone when her sister succumbed to starvation, and without a teacher, somehow mastered the hunting of small prey—striped skunks were her specialty for a short while. She survived an attack by a bald eagle that picked her off the ground, as well as sharing carcasses with grizzly bears exponentially larger than herself. It was as if her naive innocence protected her rather than made her vulnerable.

In the end, it  was an encounter with a North American porcupine that killed F99, that unassuming creature that chirps, chatters, and noisily waddles about with little fear. F99 will be missed; she taught us a great deal about the challenges orphaned cougar kittens face in the Northern Rocky Mountains. She also taught us about the will to survive.

F99, an orphaned cougar kitten, looking healthy before her encounter with a porcupine. Photograph by Mark Elbroch / Panthera
F99, an orphaned cougar kitten, looking healthy before her encounter with a porcupine. Photograph by Mark Elbroch / Panthera

For more information on porcupines, their predators, and their secret lives, refer to a copy of Peterson’s Reference Guide to the Behavior of North American Mammals. For updates, photos, and videos of F99 and other mountain lions followed as part of the Teton Cougar Project, join us on facebook.

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Sweitzer, R. A., S. H. Jenkins, and J. Berger. 1997. Near-extinction of porcupines by mountain lions and consequences of ecosystem change in the Great Basin Desert. Conserv. Biol. 11: 1407-1417.


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Meet the Author
Mark Elbroch is Director of the Puma Program for Panthera, a US-based non-profit that conducts science and conservation action to promote wild cat conservation worldwide. He has contributed to puma research in Idaho, Colorado, California, Wyoming, Mexico, Washington and Chile. He earned his PhD at the University of California, Davis, where his dissertation research focused on puma ecology in Patagonia in the presence of endangered humeul deer. He has authored/coauthored 10 books on natural history ( and numerous scientific articles published in peer-review journals.