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Unusual Beaver Activity

Beavers are known for their ever-growing incisors which allow them to cut trees down, eat the cambium (a nutritious layer just beneath the bark) and cut what’s left into pieces they are able to haul and use as building material for dams and lodges. More often than not, it’s straight forward work.

Occasionally not every step is taken – you can find standing trees that had the bottom three or four feet (as high as the Beaver could reach) of cambium removed without the trees being felled.  You can find de-barked logs that have been left where they fell and not carried or floated to the dam or lodge as construction material.  It’s also not unusual to find standing trees where several times a Beaver has attempted but failed to cut all the way through.

Recently John Twomey brought to my attention a tree felled by Beavers unlike any other I’ve ever seen:  one or more Beavers had cut down a Paper Birch and eaten the cambium layer, leaving the tree clean of bark.  At some point they cut into the tree every 18 inches or so, not quite severing the pieces, but leaving them connected by a core of wood that ran the length of the tree. If any readers have seen anything similar to this, or if you have an idea as to why Beavers would have cut the tree in this fashion, Naturally Curious would love to hear from you.  (Photo by Prentice Grassi of his sons investigating said tree earlier this spring.)

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49 responses

  1. Clearly they are making kitchen spoons!

    May 29, 2020 at 7:07 am

  2. Lynne Woodard

    That’s just crazy!

    May 29, 2020 at 7:07 am

  3. Chris Child

    Looks like firewood for their lodge!

    May 29, 2020 at 7:10 am

  4. Mary Waugh

    Don’t you love a good mystery? Fascinating!

    May 29, 2020 at 7:15 am

  5. janetpesaturo

    To me this suggests they needed the food but didn’t need the building material, but there is some hard wiring to their cutting the log into sections manageable for carrying. In other words, cutting it into suitable sizes for carrying isn’t something they necessarily think about – they just do it. If they then need it for building material, they’ll eventually it away. If not, they’ll leave it there.

    May 29, 2020 at 7:20 am

  6. An art project!

    May 29, 2020 at 7:28 am

  7. Nancy Condon

    Wow, a buoy line for their swimming area!

    May 29, 2020 at 7:57 am

  8. Vicky Linville

    Like the rest of us, Beavers are tired of being confined… so they’ve found new ways to be artistic!

    May 29, 2020 at 8:03 am

  9. Suzanne Weinberg

    Incredible! Idea — Maybe since the kits take 3 years to “fledge” there’s a period of learning the skills of 1) dental care (keeping the teeth under control) and 2) preparing logs for construction, but if the lodge or dam are not in need of any repair, they leave the material in place? Kind of a beaver version of “play”?

    May 29, 2020 at 8:09 am

  10. Vicky Linville

    Dear Mary, I recently snapped this photo early one morning last week. Do worms mate? These two night crawlers look pretty hooked-up to me! Vicky Linville Weston, VT


    May 29, 2020 at 8:12 am

  11. Alice

    A wooden necklace for a Giant.

    May 29, 2020 at 8:26 am

  12. Rachael Tolman

    Wow! This is amazing!

    May 29, 2020 at 8:27 am

  13. Crazy! Maybe they had a family reunion and the tree was the table and meal….

    May 29, 2020 at 8:43 am

  14. Young boy scouts, with their first hatchet in hand often produce cuts that are critically called “beaver work”. That phrase is all the more true after seeing this. (I don’t suspect boys at work here.) Thanks for posting this remarkable event photo.

    May 29, 2020 at 9:10 am

  15. Clyde

    Their version of “social distancing”

    May 29, 2020 at 9:31 am

  16. Sally

    Fascinating. Andrew Goldsworthy move over.

    May 29, 2020 at 9:43 am

  17. Elisa Campbell

    Beavers killed this good-sized White Ash but the roots of the tree are vigorously sprouting

    Elisa Campbell


    May 29, 2020 at 9:52 am

  18. Sue Wetmore

    Maybe they were auditioning for a Lincoln Logs job. Those of us old enough to remember these play things.

    May 29, 2020 at 9:56 am

  19. janet English Griffin

    while my knowledge of beavers is limited, the name Twomey drew my attention as a Finnish friend of mine was born a Twomey. One of the careers her father had was as a lumberjack early in the 20 century. She served in the army during WWII as a Supply Sgt.

    May 29, 2020 at 11:14 am

  20. Nancy Blasi

    Those beavers are artists! They sculpted the wood into an environmental sculpture a la Andy Goldsworthy. Go beavers!

    May 29, 2020 at 11:34 am

  21. Nancy Blasi

    Those beavers are artists!

    May 29, 2020 at 11:36 am

  22. Jean Bergstrom

    Hi Mary,

    Great picture. I have a similar one to share with you if you’d like. It is not quite as elaborate as yours but the same idea. I have no enlightening idea as to what’s going on here though. If you want to see the picture. Let me know how to send it to you. Thanks for all of your wonderfulness.

    May 29, 2020 at 11:43 am

  23. I have two ideas:

    1) Maybe they were having fun!

    2) Beavers, like all the other creatures, haven’t read our rule books about how they are supposed to behave. Life for them, as for us, is an improvisation!

    May 29, 2020 at 12:28 pm

  24. Marc Sevigny

    Looks like the work of an artist!

    May 29, 2020 at 12:40 pm

  25. Michael Hussin

    Yes we just recently saw this by a pond between Williamsburg and Ashfield. Very similar to the picture you showed. Evenly spaced chewing , 75% percent of way thru precisely spaced many next to other. Bark stripped. We thought it looked like a beaver lunch counter

    May 29, 2020 at 1:05 pm

  26. Annie

    Hope you received the most awesome explanation from David Parker. He said he had finally seen them doing it ! Trying to get a Tree down that was hung up, like you would with a chainsaw ! All I could think of were those floating markers at swimming areas, telling where you are allowed to swim, LOL. Thought the beavers might need their own space for social distancing, ha ha. Until David answered what he has seen. He has been watching closely for a few years at least and has quite a few observations. And most awesome photos. Thanks for posting such a cool mystery and an awesome Naturally Curious ! Annie Kellam. Putney >

    May 29, 2020 at 2:36 pm

    • I know that David’s explanation is accurate for most trees that you find cut into, but they usually cut all the way through when they’re trying to fell a tree that’s caught. They don’t leave a core of wood connecting each section to the next…so odd!

      June 1, 2020 at 11:45 am

  27. Lou

    I have seen large trees felled by beavers. The upper branches are gone or stripped of bark. The main trunk is mostly untouched. Now this was a medium sized tree, with tasty bark. MY GUESS FOLLOWS —–So the tree was felled,branches and trunk eaten and then cut up for a lodge or dam. Since the trunk was eaten as well as the branches, the trunk was a candidate to be hauled away. Alas Too heavy.

    May 29, 2020 at 3:00 pm

    • But why not cut each section completely, not leaving a core of wood connecting them?

      June 1, 2020 at 11:43 am

  28. Richard Putnam

    Saga continues; observed bark peeling now attributed to curious grand daughters.

    Sent from my iPhone


    May 29, 2020 at 5:19 pm

  29. David Parker Jr

    I have seen this before. It happens when a tree they fell gets hung up on another tree. Just like we might with a chain saw, they move down the tree and make another cut, which causes the tree to falls little further. They keep making cuts until it finally falls to the ground. Took me years to figure this out, but finally saw them doing it one time and it all made sense. Pretty amazing and also very dangerous for them when this happens.

    May 29, 2020 at 5:45 pm

    • Hi David,
      I am aware of that practice, but they don’t retain any of the wood between the section, rather cut right through. This has a small core of wood connecting all of the sections!

      June 1, 2020 at 11:40 am

  30. Peter Kallin

    Saw something similar once although not quite to that degree and without the bark stripping. A beaver attempted to fell a tree (don’t recall species, I think either birch or poplar) near a lake. After making a cut, the tree fell off the stump but got caught up against another tree. Beaver tried to take it down again, making a cut about two feet up, same result. Beaver now had two two foot lengths on the ground but tree still leaning. Tried again, same result. Now beaver had three two foot lengths on the ground and tree still leaning. Beaver gave up for the night, one of my friends found the tree and sent me a picture. Next night, beaver came back, tried again, same result, another two foot length on the ground. Tried one more time and tree came down, fell in the lake. Beaver (s?) dragged off the tree, leaving four 2-foot lengths behind. Wonder if something similar happened here, with the beavers stripping the bark in between. Got to admire their persistence but think it might have been easier just to start another tree.

    May 29, 2020 at 5:46 pm

  31. wildlifetracker

    I find aspen and birch are sectioned into 2.5 to 3 foot length pieces when they need to drag it into water from a decent distance. This mimics that behavior, but is illogical in length. My guess is that this is a low IQ beaver applying somewhat normal behavior.

    May 29, 2020 at 6:39 pm

  32. Sue

    So Interesting! I came across something similar last month her in northern Michigan. I have wondered what that was about. Making giant dreidels? A couple pieces had been rolled out of the line. I had posted it and a friend in NC said he once came across something similar. Sounds like it’s more common than I thought. Though, I’ve come across many areas active with beaver and this was the first. I can send a pic if you want. Where?

    May 30, 2020 at 9:23 am

  33. Winifred Lutz

    I think you are looking at documentation of a prank by a wood carving sculptor.

    May 30, 2020 at 10:08 am

    • You might think so, but I’ve had extensive communication with the person who sent me the photo (his friend took it) and I am sure it’s for real!

      June 1, 2020 at 11:37 am

  34. Constance Lentz

    I’ve never seen anything like that. It’s amazing

    May 30, 2020 at 11:19 am

  35. Ellen Blanchard

    Several years ago we found several such logs shaped by beavers while cleaning up leaves on the pond edge. Ours were 6″ long and shaped liked little footballs.
    We imagined the Dad beavers were carving toys for the “kids” to play with!
    We’ve never found any since then.

    May 30, 2020 at 12:28 pm

  36. Chris Runcie

    Hi Mary, I think I read a description of this by Berndt Heinrich a few years ago. In that case the tree was being held up by other trees in the canopy. After being severed by the beaver, it slipped straight down instead of falling over – being held up by its branches. So the beaver worked on the next section until the tree descended again, and so on. I have a chunk just like one in your picture and always wondered about it. Does this seem like a likely explanation? We can’t remember where we read his description, but we both think it was Heinrich.


    May 31, 2020 at 8:58 am

  37. Suzanne Weinberg

    OK! With the help of Chris Runcie, above, and Google (I love Berndt Heinrich):

    May 31, 2020 at 9:15 am

    • Thanks, Suzanne. Wonderful article — but Berndt also was puzzled as to the last few cuts that only went partially through the tree trunk(that was on the ground). It’s the fact that the pieces are still connected by a core of wood that is the unexplainable part to me! I understand the successive cuts made to a tree that is caught up and needs to be freed from surrounding trees…but I don’t (and neither does Heindrich) understand the purpose of not cutting all the way through!

      June 1, 2020 at 9:36 am

      • Suzanne Weinberg

        In re-reading it, it’s not clear to me that he checked the tree every single day (though knowing him, he probably did). I wonder if the tree, with the last few gnaws, sank enough for them to get some of the branches but not all, maybe bent where the partial cuts were and so they ate and then came back for another stage? But didn’t need to gnaw all the way through to get the branches low enough to get?

        June 1, 2020 at 11:45 am

  38. Rebecca Buzzell

    I forwarded this to the Algonquin Research Station. They checked with a group of naturists and no one had observed this behavior
    – very interesting!!

    June 1, 2020 at 12:24 pm

  39. Caryl Buckley

    Mary –

    Re your Unusual Beaver Activity post with the photo from Prentice Grassi:

    I’m a skeptic to the extent that I’m convinced that the photo has to have been at least partially staged by someone or something other than a beaver. Most if not all of the cuts appear to be all the way around the log, leaving a more-or-less central “core of wood that ran the length of the tree.” A beaver, chewing primarily with his upper front teeth, could not make all of those wrap-around cuts without rolling the log over. A few sections? Maybe. The entire log? No way! Maybe not all of the joints are actually attached and the beaver could have rolled the log a section at a time. If so, I find it implausible that the beaver would have left those sections accurately aligned with each other and with the stump (which seems to be shown at the left-hand side of the photo). Also, what is shown at the lower-right part of the photo? Another tree? The result of a fork from the main trunk? Just does not look plausible!

    I am not a skeptic to the extent that I know for a fact that beavers can do that sort of thing. The proof (which, as a child, I carried on a train from a Maine family vacation to our Connecticut home) hangs in my office. It is a log about 6 inches in diameter that has been beaver-shaped into three roughly spherical shapes connected by small central cores. Seemingly broken cores at each end suggest additional spherical shapes might have broken off before I found the curious item. It is clearly almost identical in nature to what is shown in the Prentice photo! Here’s a photo of my example:

    I have at times speculated that each almost-complete cut is the result of one night’s work on a standing tree and that, at the start of the next night’s work, snow has melted or accumulated, or the water level has fallen or risen, requiring the beaver to start over at a new elevation. I don’t really believe that, and it is of course completely implausible for the much longer array shown in the photo.

    That leaves me baffled! It is my understanding that a beaver’s wood-cutting teeth grow relentlessly and that the beaver must chew to keep them at the right length. Are the cuts shown in the photo, and on my smaller example, the beaver equivalent of going to the gym to keep in shape? Why stop just short of severing that central core? Pride of craftsmanship? And why the uniform spacing? Is there a ‘social distancing’ instinct analogous to the one that results in uniform spacing between birds perched on a telephone wire?

    I hope that someone can dispel the mystery!

    Jere Buckley (a friend of Tony, Sally, and Prentice Grassi, and Polly)

    June 1, 2020 at 12:30 pm

    • Love reading your thoughts, Jere. If you’re a friend of the Grassis, perhaps you could ask them if it was staged. I really doubt it, though you make very good points!

      June 1, 2020 at 12:53 pm

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