From the Field

You Won’t Believe What Porcupines Eat (And No, Not Bigfoot Bones)

Yes, the porcupine eats foliage. But will it also eat your face? Photo: ©Janet Haas

Be sure to check for porcupines when you make a late-night bathroom run.

This is one of the first things you learn upon arriving at Scout camp in the Pennsylvania woods.

The adolescent mind has no trouble imagining various exceedingly unpleasant scenarios that could emerge from such a midnight meeting. Ouch.

And unlike most of what I learned at Scout camp, this bit of lore was actually based on truth.

Porcupines really do frequent backwoods outhouses.

Because they eat them.

A porcupine finds a salty snack = plywood + urine. Photo by Education Specialist/Flickr through a Creative Commons license.
A porcupine finds a salty snack = urine + plywood. Photo by Education Specialist/Flickr through a Creative Commons license.

I’m serious. I know that porcupines are kind of like over-exposed celebrities. They attract rumor and tabloid-style coverage, most of it myth. This is to be expected for something covered in barbed quills.

But this story is true. It’s well documented in the literature, and it’s based on porcupine physiology.

North American porcupines (Erethizon dorsatum) feast on a high-potassium, low-sodium diet of foliage, causing them to excrete high levels of sodium. This creates a sodium-potassium imbalance.

While research has shown that porcupines can physiologically tolerate this imbalance at times of the year when their mobility is limited (like during heavy snowfall), most of the year they have a craving for salt.

They often seek out natural mineral licks for their needs. But the human environment is not low in sodium. We have created a salty feast for the porcupine.

Like outhouses. Urine is high in sodium. Combine this with the notoriously bad aim of boys, and you have porcupine nirvana.

The walls of my old Scout camp outhouse looked like they had been run through a wood chipper, so heavily were they gnawed by quilled rodents.

Rodent. Covered in barbed quills. And it's coming for your car, your guns, your house. Photo: © Alan D. St. John
Rodent. Covered in barbed quills. And it’s coming for your car, your guns, your house. Photo: © Alan D. St. John

What else does a porcupine chew?

The salt craving leads the critter to all sorts of strange places. Some items on this list are cited in the literature; others seem more anecdotal. And at least one is just flat-out crazy.

Cars. Roads are de-iced with salt in the winter. This salt coats the car tire and splashes up underneath the auto body. As night falls, the porcupine stealthily chews on car parts, many of those parts out of sight of the owner.

This created a harrowing situation for nature writer and ethicist Tovar Cerulli:

[The porcupines] had nibbled through a brake hose… a problem I discovered on the way to work the next morning, when my foot went to the floor without slowing my pickup at all. I was grateful for a long driveway and a hand brake. The truck—our only vehicle at the time—was out of commission for three days while a replacement hose was located.

Cerulli writes eloquently of cultivating a mindful relationship with wildlife. This incident tested him. Sorely.

Axe handles and canoe paddles. Human engages in vigorous activity. Sweats on tool. Gets tired. Leaves tool outside. Porcupine eats.

Firearms. The porcupine practices a unique form of gun control. It eats them.

Like the previous example, this one relies on a sweaty outdoors enthusiast leaving a tool outside. This is a particular favorite of pulp outdoor literature.

But like other staples of this genre – charging wolverines and the big one that got away – it seems to happen more in print than in real life.

Saddles. Horses sweat too. Especially horses on long backcountry pack trips. I imagine salty leather is somewhat akin to the porcupine version of beef jerky.

Your face. The Catskill Mountaineer offers this tantalizing sentence: “Hikers have reported porcupines licking their skin while sleeping.” Really? I cannot imagine waking up to a kiss from a quilled rodent. Has this ever actually happened?

But in case you’re thinking about not rinsing off your face after a hard day’s hike on the Appalachian Trail?

Well, you’ve been warned.

Porcupine chew marks. Would you want this on your face? No, no you would not. Photo: WIkimedia user Cephas under a Creative Commons license
Porcupine chew marks. Would you want this on your face? No, no you would not. Photo: WIkimedia user Cephas under a Creative Commons license

Plywood. The resin used to bind plywood is sodium based, making it an ideal porky snack. There is a patent for “porcupine proof” plywood, based on a potassium resin, but it doesn’t seem to have caught on.

Porcupines used to be considered a much bigger problem for home owners. In the 1800s, when pioneers kept large quantities of salt in their cabins, porcupines reportedly chewed through walls at night to get at the stash.

Porcupine snack! Photo: Matt Miller/TNC
Porcupine snack! Photo: Matt Miller/TNC

Antlers. Antlers are rich in minerals and shed every spring. It’s a veritable feast. Provided the porcupine beats eager shed hunters.

Bigfoot bones. Faces, and gunstocks, are at least in the realm of possibility. This one belongs to science fiction, and is almost too silly to mention.

But start researching porcupine diets and you’ll soon land in Bigfoot’s lair.

Cryptozoology fans posit that the reason no one ever finds the bones of dead sasquatches is because – you guessed it – porcupines eat them!

Of course they do.

This idea was popularized on the regrettable Animal Planet show Finding Bigfoot. Of course, this is the same bastion of journalistic excellence that claimed sasquatches are attracted by raves.

Sasquatch tracks? No. It's a porcupine. Photo: Wikimedia user Lensim under a Creative Commons license
Sasquatch tracks? No. It’s a porcupine. Photo: Wikimedia user Lensim under a Creative Commons license

Porcupines do dine on bones. But anyone who spends much time poking around the woods knows they don’t eat every bone in the forest.

Not that this fact is likely to dissuade the True Bigfoot Believers. It can dissuade the rest of us from regarding cryptozoology as science.

Tree bark. Once, society regarded porcupines as a major nuisance. This was based not just on its love of salt, but also its dietary staple of tree bark.

Anything that girdles trees must harm the timber industry, or so conventional wisdom went at the time.

Many states paid bounties on dead porcupines until the 1920s (and in the case of New Hampshire, until 1979). When actual research was conducted they found that this was untrue. Not “porcupines eat sasquatch” untrue – but in no way a major factor in timber harvests.

The reintroduction of fishers, a major porcupine predator, keeps their populations in check.

Today, porcupines can be at worst a localized problem – although a not insignificant one is your car has no brakes or you’re literally up the creek without a paddle.

Still, they’re fascinating critters. Just keep your valuables out of reach, and watch where you sit in backcountry outhouses.


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  1. Hi Jon,
    Have just read your blog about porcupines with great interest.The “B’S” are back here hungrier than ever. They have literally devastated everything with a tuber, or corm in our garden in the last few days.
    David and I have come to loathe the critters.
    Hope you’re well
    Ciao for now,
    Eleanor and David

  2. Reading this brings back the thrill of driving down unpaved roads in Vermont in a VW bug with no brakes. Eventually we hit upon the plan of totally enclosing the vehicle in wire upon arrival at the weekend cabin. Labor-intensive but effective. The population of porcupines was so high one year that the departed were buried vertically in the garden (to save space).

  3. I sure hope this article doesn’t incite a porcupine killing spree across the country.

  4. Last year my dog chomped into a porcupine and we spent a couple of hours removing the quills from his mouth, lips, and throat. Not fun. A couple of nights ago I heard scratching on my house and I thought it was Kitty, wanting to come in. I opened the door and about 18 inches from me was this glorious round ball of pure white quills! It looked like some kind of Christmas ornament. Now, I am worried about my car, my cats, and myself. What to do…..

  5. I had those distinctive chew marks at all around the support logs on the porch of our home in MT a couple of summers ago. I had no idea what that was from…neither did anyone else! Then one night my dog was barking and I saw a large lump of quills or fur…I wasn’t sure…moving around the deck area. There was no front or back that I could tell! It ended up in a corner…apparently it was a large porcupine. That’s what had been feasting on the logs…so I had them ringed in a copper skirts to stop it from chewing around them.

  6. Great Article Matt! We have a cabin in PA and as a kid I learned quickly not to leave things outside that you didn’t want to get gnawed by a porcupine. I don’t recall ever having issue with our outhouse, but chairs, axe handles, vehicles, were all regularly chewed on. We’ve had more than one person stranded up there after porcupines chewed on their vehicle.

    Thanks for the memories.


  7. Hiking in Mt. Rainier National Park, we noticed a deposit of quills at the edge of a platform toilet(comes with a view). Does a porcupine leave quills as a down payment on such a fine piece of property? There were no visible chew marks – yet.

  8. Would love to find a method short of shooting them to stop the destruction of my dwarf pear trees. They break all the branches when climbing to get to the fruit. Have tried all kinds of methods but the lowest branches are too close to the ground for metal trunk wrap to work. They dug under a solid metal fence placed a couple of feet away-didn’t know they would dig like a ground hog. Won’t enter a live trap. Might have to resort to elimination via bullet. This guy comes out most anytime it wants-even mid-day doesn’t stop it.

  9. Ah, finally a nice article about my favorite critter. Porcupine numbers appear to be declining just about everywhere. Enjoy these adorable forest/grassland/desert denizens whenever you see them.

  10. The captions under the pictures really made this article all the more enjoyable for me

  11. Im a big foot believer but yes that show is ridiculous; anyway lots of creatures gnaw on bones its part of the forest cycle. But my interest was, would they shred pine cones and leave a pile of seeds almost as if they sucked on the inside like we would on a ear of corn after devouring the kernels? yes this is related to sasquatch activity.:).

  12. I used to see porcupines regularly in my rural area of Washington state, and my dog had an occasional encounter. But I haven’t seen one for literally years now, and I know they have a lot of enemies around here (orchardists, loggers, vehicles). I find it ironic that Washington state’s Dept. of Fish & Wildlife is working on restoring fisher populations (for which porcupines are a major food source) but still instructing people about how to trap and exterminate porcupines. And I don’t think the state has done any study of porcupine populations to learn about population trends.

  13. If foresters hadn’t killed the porcupines, they wouldn’t have to spend so much money and time thinning forest to prevent fires now.
    The critters are nearly extinct in Southwestern Oregon.

  14. Great article. Despite Pine-sol, Havoc, wasp spray and thumbtacks, a porcupine continues to wake me from my sleep gnawing on the deck bolsters.

  15. WOW. Thank you for all that you have done & will continue to do to save OUR EARTH.

  16. They also like pack straps, as a friend found, to her dismay, on a backpacking trip, and boots (preferably not on your feet).

  17. what can you use to keep porcupines from chewing your steps that you have put salt on to keep
    the steps from getting iced up?

  18. Keep your backpack and your boots out of porky reach when you’e camping — the sweat on them attracts the beasts, who’ll chomp on them, too.

  19. I have an injured porcupine living on my property and the only thing it will eat is the leaves of cedar trees.

  20. How can we get rid of one that is destroying our weekend cabin during the week

  21. We have a porcupine that visits every day; he is fantastic. One has to be sensible. I even can pet him without a glove. People are sick to demonize animals so much. I absolutely feel that when you drive your car that is far, far worse than any porcupine that waddles by. No porcupine is ever going to attack your face. Your car, on the other hand, could.

  22. I live pretty much in the woods. I have a beautiful Kentucky Bluegrass lawn in the front with lots of yews and flowering plants. I also have a porcupine that lives under my shed. Poor thing must be 100 years old; partially bald and missing most of its quills, it wanders around my yard only eating my lawn. He doesn’t dig; he just grazes. I feel really bad for the poor guy. I’m thinking he may have lost some teeth. Sometimes I just stand there and let him graze. He ignores me and we have a 10′ “personal space” agreement. If he gets too close to other fauna, I shoo him away with a broom. He waddles under my deck and “hides”.

    My back yard is 20 feet of weeds, grass, and creeping ground cover, separating my home from forest. I know this is crazy, but I am thinking of growing a 5′ x 10′ patch of KBG just for him. 6 weeks to 2″ grass height….Yep, I’m retired, so I have the time.

    Would salt licks strategically placed in the back of the back yard attract the little guy? Salt licks attract deer, but I already have a dozen or more deer who come within 10′ of my front door. I own a weapon, but I wouldn’t shoot at anything with 4 legs…with the exception of fishers.

    1. Aww, that’s so cute <3 I hope he is ok, and that you did indeed grow the grass just for him. I wonder what else he'd like… maybe some small evergreen trees? or lettuce? We take lettuce that's going off and feed it to the geese! Spinach too! What did you end up doing? Thanks 🙂 Rachel

  23. Have you ever heard of porcupines chewing pex waterline piping under camps in the Adirondacks? Six lines have been chewed and so much porcupine poop that its mountains high. Also they have chewed the electrical lines. How do we get rid of them?

    1. Yes, they will chew piping and can do various damage to cabins. I would suggest contacting your local fish & game officials for help.

  24. Chapter 2 My visiting porcupine:
    I decided that it would be safer for my kitty if Porky were not around. While Porky was out and about, I placed a few bowls of ammonia at his entry point under my shed. Sure enough, he was gone the next day. So was my cat. She usually came home before dusk, but that night she was a no-show. I went looking for her and about 300 yards down the road, I discovered her lying down within 20 feet of Porky.
    The following day, kitty was sitting on the bottom step of the deck and Porky appeared from around the corner. He passes with 2 inches and neither flinched. I guess I have a permanent guest. My only worry was harm to either of them, but I think I can rest easy.

  25. This is wonderful.
    Do porcupines eat human food like rice, beans, yam etc?
    Must their food be salty?

  26. This was absolutely Hilarious AND informative. This author is Brilliant, & HE probably won’t eat / lick your face . That a discussion with 36 wonderful remarks on this subject , is this popular makes it even more impressive. Now, I’ll tell you something even more quirky. I’ll just bet you, everyone would let these ” Pretty Pouty faced porcupines'” eat their houses , automobiles, trucks, tires, outhouses, & their favorite pet, before they’d let him eat their Cell Phones with their whole lives on them. ! ( That’s why I don’t have one ) Cheers . From across thee pond ( Thee Hudson river , I now live in Manhattan New York City LOL ) Cheers & GOD bless from Natasha Veruschka

  27. They also climb up street sign poles and eat the entire metal street sign right down to the center bolts.

  28. Hey Matt

    I am reaching out from northwestern Ontario. You are obviously a porcupine expert and I am wondering what a porcupine feces or toilet area looks like, any idea on that one? we have a few up here but I found an odd toilet area and I have spent a life time in the bush and can not identify it and it leads me to think porcupine by the process of elimination.

    1. Hi Vern,
      Porcupine scat can be variable, but it often looks like pellets — think thicker, more elongated deer scat. I have found porcupine toilets that have a pile of pellets that have lots of pine needles in them. Many were even green pellets. I have seen other porcupine pellets with lots of woody material in it. It is in a large pile, as porcupines often stay in a tree for a while. Hope this helps. Matt

  29. Haaa! That was really funny and very intelligently presented! Thanks a lot 😀 I learned a lot about porcupines 😀 I have also heard they like to hide in culverts in small prairie towns 😉

  30. Recently my neighbor has had a young porcupine eat off all the foliage on her huge cedar tree. Could it be starving and need more food.? What else could you feed it?

  31. The dog pen has a nightly porcupine visitor, now I know why. Fido goes elsewhere after dark now. Would it help to hose down the area?

  32. Love the comments on porky’s. I’m 83 and I’ve run into a bunch of these pesky porky-habits.

  33. Great article – most informative.It started with one.

    He was cute and didn’t bother anything. He enjoyed the clover in the front yard and the dogs enjoyed watching him from behind our very large fenced back yard. Occasionally he would wander, always respectfully, down the outside of the fence – much to the dog’s delight. As the woods have crept in closer to the yard, the dogs now go out on leashes in the fenced yard at night for last call. Just in case.

    This year the resident porcupine is huge and arrived with a partner. Recently I’ve been awakened by the strangest noise – like gears turning slowly. Tick. Tick. Tick. I was convinced something was living in my house but found…nothing. It seemed to be coming from the front steps. I went out the front door and if I hadn’t seen the white quills sticking out the side under the deck I’d still be wondering what that noise was.

    I’ve managed to block up some of the space under there but last night he and the partner were back. This morning I found some of the spots where they were chewing. They are also digging in the garden perhaps for bugs?

    So, I had the same question – if I tossed a salt lick off into the trees would they be more apt to leave my steps alone? It’s pressure treated wood and I use pet friendly de-icer in the winter – never thought of it as ‘salt’. I hesitate to block off the steps completely, or even use ammonia fearing they will start on the house or dig their way into the back yard. I’m trying to find someone to come and cut back the encroaching forest hoping that might help by leaving their escape route more exposed.
    I don’t mind them grazing or using the trails they’ve established but I can only deal with so much.

  34. Excellent, holistic, truely scientific article. And LOL. Thank you so much.