The splendid and assiduous beaver

March 15, 2015 • 2:30 pm

This National Geographic documentary on beavers (Castor canadensis) and their dams (the classic example of an “extended phenotype” as well as “niche construction”) is very good, and well worth watching if you have 45 minutes to spare. Why would anyone watch a reality t.v. show about the Kardashians if they can watch a reality show about beavers?

There are two named species of beavers—the other is the Eurasian beaver, Castor fiber, but I don’t know why they’re classified as separate species. Would they be reproductively isolated were they to live in the same area?

 

62 thoughts on “The splendid and assiduous beaver”

  1. “Why would anyone watch a reality t.v. show about the Kardashians if they can watch a reality show about beavers?”

    As if taken from my own mind……

    1. I know I could come up with a good reply involving “beavers” but it’d be rude and besides, it’s more about “bottoms” with the Kardashians. 🙂

      1. I’d never have heard of the Kardashians, but producers will keep putting them on proper news shows. All I’ve worked out is one has a big bum, which she had x-rayed to prove it was all hers, and they make money from being stupid and beautiful and letting their mum run their lives. There seems to be a bit of an obsession with the letter “K”, and there are three daughters (I think), thus proving anything called KKK is mindless and deserves far less attention than it gets.

        As for the documentary, I think beavers (the animals) are amazing. I’d love to see one in real life.

        1. I saw a cute one at a science centre in Sudbury. The beaver was cute but I don’t want to meet one in the wild as they can be jerks and bitey.

          1. One of the books I had read as a child was about a family that kept various wild animals. One was a beaver who loved to be cuddled. It would throw a tantrum until you picked it up and rubbed its tummy.

        2. I wish to hell they’d get off of that “K” thing. It was cool when it was Ken Kesey and Kris Kristofferson, but these Kardashian people are ruining the double-K brand. To paraphrase the old Melanie song, Look what they’ve done to my initials, Ma, look what they’ve done!

  2. Why would anyone watch a reality t.v. show about the Kardashians if they can watch a reality show about beavers?

    …joke… …must… …resist…

  4. “Why would anyone watch a reality t.v. show about the Kardashians if they can watch a reality show about beavers?” Aren’t these synonymous?

  7. Why they are classified as separate species? I dunno. But if they can interbreed and make viable offspring who are also fertile then we can declare them ‘good’ species.

    1. Not if they’re ecologically isolated; that is, they prefer different habitats where they’d never meet–or they find each other completely sexually repulsive or the breeding seasons don’t overlap.

      I don’t know about the hybridization results.

    2. They don’t interbreed. The European species has 48 chromosomes, the American one 40; they differ by several robertsonian fusions with monobrachial homologies. I don’t remember the details of this case, but that means that primitive chromosomes are combined in different ways in each species. For illustration’s sake, you could have chromosomes a/b and c/d in one species versus a/c and b/d in the other one. The result would be unbalanced gametes and sterility in hybrids. In the case of beavers, it is even worse, the hybrids are not produced at all – or more probably die in a very early developmental stage.

      1. I looked for a reference:
        Ward, OG et. al.,1991: Cytogenetics of beavers – a case of speciation by monobrachial centric fusions. Genome 34 (3), 324 – 328.

      2. Well, since they are reproductively isolated in every sense, then it seems they should be considered separate species.

        1. There are many species in common with Eurasian species in North America of course, largely because of Beringia – the Eurasian species went east. Brown bears & grizzilies are the same species, elk/moose are the same, caribou/reindeer, wolves, bison have speciated – became extinct in Asia for reasons of habitat loss/change I suppose…

          Did any North American species go west?

          3. Yes! – I was thinking more recently. Camels also went west… Elephants went east earlier on…

    1. I’ll add one good thing about that beaver, though. Since there was a storm forecast soon after I found that tree, I had to cut down all the upper branches to make sure the storm didn’t blow it over onto the deck. I finished up just before it got dark on a Sunday, and was planning to go back down there the next weekend to clean up the mess. By the time I got there, almost all of the smaller branches had been chewed off and drug into the water, so all that was left for me to do was cut up the big branches into firewood. It really proved out the old adage of a ‘busy beaver’.

      My only other somewhat interesting beaver story was when I was hiking in the Adirondacks with my parents. It was their first backpacking trip (I’d backpacked a lot with Scouts and friends), and the whole trip ended up being a bit of a fiasco (though very fun to reminisce about). At one point, the trail led straight into a beaver pond. We had to work our way around quite a ways before we were able to find the trail again.

    1. There are bears in the documentary too – looking to nom beavers mostly – which sets up another joke idea on the way for for Diana MacP and pacopicopiedra.

        1. That’s great to hear! Double entendres shouldn’t be a reason for giving up the connection to a marvelous creature. Also, double entendres are the best! The fact that otherwise mature people snicker when they say a word out loud is a delight.

  16. PBS aired an excellent program titled Leave it to Beavers on their Nature program last year. I loved it, and became a big admirer of beavers after I watched it. I would highly recommend watching it. I would be all for making beavers honorary cats!

  17. Wonderful video. I enjoyed it and learned a lot, despite being a ‘Beaver’ that is a graduate of Oregon State University, many years ago. No beavers that I know of in Australia!
    I’m interested in the beaver’s digestive tract. It sounds like their diet is similar to that of the Giant Panda, who survive partly by being very inactive.

          1. I LOVED that Juluan Barnes book! Also Not Wanted on the Voyage, by Timothy Findley, in which the kitteh is felina non grata on the Ark.

  18. I’ve lived in beaver country in Minnesota for over 25 years and have seen them in the wild many times. They are incredibly industrious. On a wilderness trip I have encountered a dam that covered the whole width of a small river and provided a platform for 8-10 people or more loading canoes. The builders complained with loud tail smacks that souned like a boulder being tossed into the water. I don’t have the reference, but I believe the dam building behavior is triggered by the sound of running water. They keep at it until it stops or is reduced sufficiently, but I dont know how that was determined. Water depth for the sake of building a lodge with adequate safe underwater entry may be another factor, but lodges are often built in areas where no dam is required to create the depth of water needed. Someone else may know the animal behavioral science much better than I do.

  20. Good video. Made me wonder the difference between a beaver and a woodchuck, until googling revealed that a woodchuck is a groundhog. I wonder if I ever knew that and had forgotten it…

  21. Fascinating aren’t they? I had no idea how many there were in my immediate vicinity until my enforced rest from work. I’ve lived here in NS for 30 years and never knew just how many beaver ponds are within walking distance. I have photographed dozens of the things. Sadly, I have also watched them grow until a local farmer comes along with a backhoe and destroys the dam, usually just before cold weather so there will be no time to build a new one before winter. When I first came here I had a patient who worked for Lands & Forests who used to take a stick of dynamite to annoying dams. Unfortunately for him, ‘mistakes were made’ and he blew himself up. He was a nice guy, but all the same, one would like to give a tiny cheer for the beavers too!

    1. Sad to see that kind of terrorism. My brother-in-law had some low land (MN) the beavers would flood every year. On his own land he would tear the dams down, but a critical dam was on his neighbors property and the guy would not cooperate in the campaign of destruction. My brother-in-law took his case to court and won. The neighbor finally did the wretched deed.

  22. I had always thought of beavers as creatures of the Adirondacks until this fall, when trees started falling near our Newport YC clubhouse on the shore of Irondequoit Bay, close to Rochester, NY. There’s no dam building going on (it’s a big bay that opens into Lake Ontario), just a family of beavers living in the bank and (still) eating bark from the branches that they stored under the ice of the bay.
    For a while, we were nervous that one of the trees would fall across the road & block the plows or emergency vehicles–but it got hung up in branches & is still standing, literally attached by a tiny amount. Beavers may be good dam builders, but they’re lousy lumberjacks.

    1. They even made an appearance down here in Poughkeepsie. Felled a handful of trees along the edge of a pond, then disappeared.

  23. Do European beavers eat fish? (NA ones don’t.) I’ve always wondered about that since CS Lewis’ (seeming) mistake in LWW … then again, it would have been a bit awkward otherwise …

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