Speaker 1: Hey, welcome to Stuff to Blow Your Mind. My name
Speaker 1: is Robert.
Speaker 2: Lamb and I am Joe McCormick. And it's Saturday, so
Speaker 2: we're going into the vault for an older episode of
Speaker 2: Stuff to Blow Your Mind. This one originally published May eighteenth,
Speaker 2: twenty twenty three, and it is part one of our
Speaker 2: series on the beaver, a truly remarkable animal, far more
Speaker 2: strange and amazing than you might imagine.
Speaker 1: Yeah, so have you skipped it the first time around,
Speaker 1: thinking I don't want to hear about beavers. Beavers are boring. Well,
Speaker 1: you were wrong. Beavers are exciting and allow us to
Speaker 1: prove this to you in this episode and the following.
Speaker 3: Welcome to Stuff to Blow your Mind, a production of iHeartRadio.
Speaker 1: Hey, welcome to Stuff to Blow your Mind. My name
Speaker 1: is Robert Lamb and I'm Joe McCormick. We've covered numerous
Speaker 1: examples of this before, but obviously, in days before photography
Speaker 1: and videography, one had to depend on illustrations and written
Speaker 1: descriptions to convey the reality of an organism, you know,
Speaker 1: be it a bird or a fish, what have you.
Speaker 1: But this is especially true for creatures that lived in
Speaker 1: lands beyond your direct experience. You know, what are the
Speaker 1: what are the mammals, what are the birds? Like on
Speaker 1: another continent. Well, you have to send people out in
Speaker 1: the world. They can, you know, to a certain extent.
Speaker 1: They can bring specimens back. Certainly, they can bring parts
Speaker 1: of specimens back, but it's those ill in some cases,
Speaker 1: but it's those illustrations that really bring things alive. Now,
Speaker 1: certainly there are some fine examples of naturalist illustration out there,
Speaker 1: especially from recent centuries. I mean there's some gorgeous, like
Speaker 1: you say, like Audubond illustrations and paintings that sort of thing.
Speaker 1: But there are also countless examples, and we've touched on
Speaker 1: these before in the show of rough or drawings, drawings
Speaker 1: that feel like, you know, there's been a game of
Speaker 1: telephone at play. And this is especially the case for
Speaker 1: examples found in various bestiaries and medieval manuscripts, among other places.
Speaker 1: And when we think of such misconstrued animals, you know,
Speaker 1: what do we tend to think about? You know, we
Speaker 1: think about the rhino, We think about the lion, the whale,
Speaker 1: the elephant, you know, great animals, apex, predators, and megafauna.
Speaker 1: But in this episode, in the next episode, at the
Speaker 1: very least, we're going to get into another creature that
Speaker 1: has also experienced extreme inaccuracy in historic illustration, and that
Speaker 1: is the common beaver. Based on just some of the
Speaker 1: images we've been looking at, a beaver might well be
Speaker 1: a kind of strange dog or a pig with a
Speaker 1: with perhaps a fish tail on its body, you know,
Speaker 1: a real hybrid feeling like it is, almost like it's
Speaker 1: a strange like dog mermaid. It might be in almost
Speaker 1: all respects a deer, like a creature with long legs
Speaker 1: and hooves. And it may also look like a strange
Speaker 1: and confused rodent with a great button seam running down
Speaker 1: its chest. It may even look like a weirdly serpentine lion.
Speaker 2: So Rob has been sharing medieval and Renaissance illustrations of
Speaker 2: beavers with me for a couple of days now, and
Speaker 2: I really do love all of them. But I do
Speaker 2: think the one I like the most is the one
Speaker 2: that's just straight up a deer with hooves, except it
Speaker 2: has razor blades for teeth, just like the rectangular razor blades.
Speaker 1: Yeah, yeah, this one. I had to go deep around
Speaker 1: this one because I was It initially came up in
Speaker 1: an image search and you know, I think it was
Speaker 1: maybe on a pinterest or something. I was like, I
Speaker 1: can't trust this. But I eventually looked it up in
Speaker 1: the catalog of illuminated manuscripts and it is a Northern
Speaker 1: Italian illustration from somewhere around the year fourteen forty. And yeah,
Speaker 1: it just looks like a It is labeled as a beaver,
Speaker 1: but it is in all respects a deer. So I
Speaker 1: was just really astounded, like here, especially as an image,
Speaker 1: that it not only gets the form wrong regarding the
Speaker 1: target organism, it gets everything about like the energy of
Speaker 1: the creature wrong, you know, because it's it's one thing
Speaker 1: if you have a depiction of a rhino that okay,
Speaker 1: it's like a big armor plated thing with four legs.
Speaker 1: It's like, all right, I mean that's it's an extravagant
Speaker 1: version of the truth. But this, it's like, how wrong
Speaker 1: did this game of telephone go?
Speaker 2: Right? With the right? You like, with deerors rhinoceros, you
Speaker 2: can see that beginning as a rhinoceros, but with embellishments, yes,
Speaker 2: But with the beaver, it's like, oh, I'm sorry, did
Speaker 2: you say beaver? I thought you asked for a depiction
Speaker 2: of a of a lion with a snake neck biting
Speaker 2: its own genitals.
Speaker 1: That's right, because and this is this is something we'll
Speaker 1: probably get into mostly in the next episode, But there
Speaker 1: is this pervasive myth that existed for a very long
Speaker 1: time that when pursued by hunters, a male beaver would
Speaker 1: chew off its own testicles. And so many of these images.
Speaker 1: Be your creature more dog or catlike, or or actually
Speaker 1: just a deer with razor sharp teeth, it is often
Speaker 1: depicted nine at its testicles. That at least we have
Speaker 1: some answers for in the next episode where that idea
Speaker 1: comes from and why it's so pervasive.
Speaker 2: Right, So you've got to stick around for next time
Speaker 2: to hear that.
Speaker 1: Yeah, so let's start with what we know. Let's start
Speaker 1: with the reality. We're gonna start by talking about just
Speaker 1: basic beaver anatomy and behavior. And I probably don't have
Speaker 1: to tell most listeners out there what a beaver looks like.
Speaker 1: I mean, for starters, like, we have images all over
Speaker 1: the place of them, we have documentary footage. Many of
Speaker 1: you can go and see a live beaver at least
Speaker 1: in some sort of like a zoo environment, or you
Speaker 1: have seen them in the past. But on the other
Speaker 1: side of the coin, it's, like I said, still kind
Speaker 1: of have to tell you what a beaver looks like
Speaker 1: because the beaver is kind of in the same category
Speaker 1: as the spouting whale, as we discussed in some of
Speaker 1: our recent whale episodes, those particularly the ones on spouting
Speaker 1: and spouts. Because despite all this access to actual, solid
Speaker 1: documentary footage of the beaver, we still have this rich
Speaker 1: history of cartoon depictions of beavers that inevitably cloud our
Speaker 1: understanding of the creatures.
Speaker 2: I mean, I think you get a fairly accurate mental
Speaker 2: picture if you just cross a squirrel with a grizzly bear.
Speaker 2: You know, you mash those two up your most of
Speaker 2: the way there. But while that does get you sort
Speaker 2: of the shape the outline, right, that does not tell
Speaker 2: you everything you need to know about beavers. Beavers are
Speaker 2: much stranger and more beautiful than I realized.
Speaker 1: Yeah. Yeah, there's a lot of weird and wonderful aspects
Speaker 1: to their morphology, to their behavior, and a lot of
Speaker 1: this is stuff that our popular conceptions of the beaver
Speaker 1: don't get into. I mean, you know, they do get
Speaker 1: some of the things right, you know, the basic shape
Speaker 1: of the beaver is far better in cartoon than it
Speaker 1: is in many of these eliminated manuscripts. You know, some
Speaker 1: things hold up. Obviously, beavers are not going to sell
Speaker 1: you out to the White Witch. That's absolutely true.
Speaker 2: So C. S.
Speaker 1: Lewis was right on that count, even if he got
Speaker 1: the whole diet of the beaver wrong, because in Narnia,
Speaker 1: apparently beavers like to eat fish and chips. That's not
Speaker 1: happening in the actual natural world.
Speaker 2: On the other hand, I will say, there is the
Speaker 2: kind of food and organism usually seeks out to eat
Speaker 2: in its environment, versus what an animal will eat if
Speaker 2: given the opportunity. I kind of wonder. I feel like
Speaker 2: if you gave a beaver a basket of chips and
Speaker 2: some malt vinegar, I don't know they might get into that.
Speaker 1: All right, Well, let's start with the basics here. So
Speaker 1: beavers are rodents, and are in fact the second largest
Speaker 1: extent rodent, surpassed only by the mighty capybara. Beavers can
Speaker 1: weigh up to fifty kilograms or one hundred and ten pounds.
Speaker 1: There are two extant species of beaver. There's the North
Speaker 1: American beaver or castor canadensis and the Eurasian beaver caste
Speaker 1: or fiber. But the Castoridae family includes some impressive extinct
Speaker 1: species as well. In fact, there were giant beavers that
Speaker 1: lived during the Pleistocene, reaching weights of up to one
Speaker 1: hundred and twenty five kilograms or two hundred and seventy
Speaker 1: six pounds, So that is more than twice as big
Speaker 1: as extant beavers. Though I was reading they seem to
Speaker 1: have had smaller brains, among other morphological differences. But yeah,
Speaker 1: so they were bigger, and you know, maybe to some
Speaker 1: extent they didn't have to or had not yet developed
Speaker 1: these very impressive behaviors and abilities that we'll get into
Speaker 1: concerning modern beavers. Now, one note on these guys. They
Speaker 1: were still smaller than the fifteen hundred kilogram or thirty
Speaker 1: three hundred pound giant pacaranas of South America. Extant pacaranas
Speaker 1: only get up to light thirty three pounds or fifteen kilograms,
Speaker 1: and they can still be found in the western Amazonian
Speaker 1: River basin. But the giant ones, they were pretty massive.
Speaker 1: A lot of rodents of unusual size in freehistory, all.
Speaker 2: Right, So no beavers today in that territory, but beavers
Speaker 2: can still get pretty chunky.
Speaker 1: That's right. Yeah, they're pretty big, And this is like
Speaker 1: a fact. I frequently forget that they're the second biggest rodent.
Speaker 1: The kappy bear is easy to remember, but it's sometimes
Speaker 1: it's easy to forget who's coming in second. Now, it's
Speaker 1: extremely important to note that beavers are semi aquatic, having
Speaker 1: evolved to thrive in various freshwater habitats, so a number
Speaker 1: of the things we're going to be discussing about them
Speaker 1: line up with their habitat. For instance, they can hold
Speaker 1: their breath for fifteen minutes. They have transparent third eyelids
Speaker 1: called nicitating membranes to aid them in their swims, much
Speaker 1: like manatees. They also famously have long, flat black tails.
Speaker 1: We know this from the cartoons obviously, and these aid
Speaker 1: them in their swimming, but they can also use them
Speaker 1: to sound an alarm by slapping the water slapping the
Speaker 1: surface of the water, and they also use them to
Speaker 1: balance when they're carrying wood or other loads across the ground.
Speaker 1: For any of you out there who watch a lot
Speaker 1: of animal videos on Instagram and so forth, you may
Speaker 1: have seen videos of adorable beavers carrying carrots around and
Speaker 1: if you're not looking closely enough, you might think they're
Speaker 1: dragging their tails, But if you will look closely, you
Speaker 1: can see that the tail is off the ground and
Speaker 1: it's helping them balance.
Speaker 2: One of the things I've noticed about watching beavers try
Speaker 2: to move objects around is how much more gracefully they
Speaker 2: do it in the water than on the land. So
Speaker 2: these are semi aquatic mammals, but I don't know, it
Speaker 2: seems to me that the water is where they're really
Speaker 2: in their element. They can swim fast and gracefully, even
Speaker 2: carrying like an unwieldy branch that's kind of unbalanced or something.
Speaker 2: They do that all quite well in the water, and
Speaker 2: then once you see them sort of toddling along across
Speaker 2: the dry land that it looks much more comical and awkward.
Speaker 1: Yeah, and this is going to be important to keep
Speaker 1: in mind when we talk about the amazing ways that
Speaker 1: they transform an environment to better fit their needs and desires.
Speaker 1: Oh but before we get into that, we of course
Speaker 1: have to talk about the teeth of the beaver. This
Speaker 1: is something that is generally an important part of cartoon
Speaker 1: imagery concerning the beaver. A lot of times cartoon beavers
Speaker 1: will speak with a kind of whistle in their voice.
Speaker 1: But we also tend to get it quite wrong.
Speaker 2: Okay, so I'm trying to picture the cartoon beaver. I
Speaker 2: think what we always see is an overbite with two
Speaker 2: kind of square shaped teeth grouped right together in the middle,
Speaker 2: like a person's front two teeth, but large and overlapping
Speaker 2: the bottom lip. Is that about it?
Speaker 1: Yeah? Yeah, pretty much.
Speaker 2: The truth is much more shocking.
Speaker 1: Yeah, yeah, they have these. You know, if you look
Speaker 1: at a skull of a beaver, it's pretty markable because
Speaker 1: it's like this, the really kind of exaggerated rodent skull
Speaker 1: with just incredible incisors, you know, with these these two
Speaker 1: big shovel like teeth coming down from the top, two
Speaker 1: big shovel like teeth coming up from the bottom, and
Speaker 1: then the rest of the the back teeth or much
Speaker 1: further back, you know, giving them some ample room to
Speaker 1: do the kind of woodwork that they need to do
Speaker 1: with those chompers.
Speaker 2: The skull is a powerful bone hinge, and it's like
Speaker 2: it's like a kind of alien biotechnological set of bolt cutters,
Speaker 2: except the bolt cutters are orange teeth.
Speaker 1: That's right, The orange is key. This is something I
Speaker 1: almost never see in like a cute c illustration or
Speaker 1: a cartoon depiction of a beaver. So, yeah, these teeth
Speaker 1: have thick layers of enamel, which has this orange colorization
Speaker 1: because while other rodents boast magnesium enriched tooth enamel, beavers
Speaker 1: have iron enriched enamel. They're like, I mean, it's it's
Speaker 1: like something out of a comic book, right. The iron
Speaker 1: makes their teeth stronger against this the pure mechanical stress
Speaker 1: that they put them through. We should also note that
Speaker 1: these teeth continue to grow throughout their lives, to the
Speaker 1: point where they have to gnaw them down on trees
Speaker 1: to keep them down. But yeah, they're just super resilient,
Speaker 1: always growing, and they're also more resilient to acid as
Speaker 1: well based on their composition.
Speaker 2: Just some tough, rusty looking teeth.
Speaker 1: Yeah, yeah, the orange is really quite shyy okay. Another
Speaker 1: essential biological aspect of the beaver before getting into their behavior,
Speaker 1: is that they have a cloaca. So most mammals do
Speaker 1: not have a cloeca. There are some exceptions, you know,
Speaker 1: you look at the monotremes, golden moles, marsupial moles, ten
Speaker 1: rex just a few examples, but mammals have most lost
Speaker 1: these general purpose openings over the course of their evolution,
Speaker 1: but in beaver's they seem to be present as a
Speaker 1: case of secondary evolution, perhaps as an adaptation I've read against.
Speaker 1: It may have to do with the watery environments they
Speaker 1: find themselves in, protecting themselves against infections that might occur
Speaker 1: due to the state of that water. But it's also
Speaker 1: something and this will become important, I believe in the
Speaker 1: next episode as well. It can make it difficult to
Speaker 1: sex a beaver, as males and females look pretty much
Speaker 1: the same, unless the female happens to be pregnant or
Speaker 1: nursing at the time that you're trying to sex them.
Speaker 1: And when I say you, I of course mean people
Speaker 1: who have authority and expertise to be out in the
Speaker 1: wild trying to sex a beaver. You know, leave it
Speaker 1: to the professional biologists.
Speaker 2: Leave it to beaver scientists. Yes, so these.
Speaker 1: Various features aid the beaver in its primary enterprise of
Speaker 1: ecosystem engineering. We all know that beavers build dams, you know,
Speaker 1: this is, of course is true of the cartoons. But
Speaker 1: what does that really mean? Why? Why are beavers building dams?
Speaker 1: What are they accomplishing, So they actively alter their ecosystem
Speaker 1: via the blockage of rivers and streams with structures of
Speaker 1: like you know, sticks, mud, chunks of trees, that sort
Speaker 1: of thing, all cobbled together to dam up the water,
Speaker 1: and this allows them to create new lakes, new ponds,
Speaker 1: whole floodplains. Meanwhile, the lodges they construct for themselves are
Speaker 1: also made out of this kind of stuff, branches and
Speaker 1: mud and so forth, and they can only be accessed
Speaker 1: from underwater entrances in their constructed ponds.
Speaker 2: Yeah, so this is something I don't know if I
Speaker 2: realized before. I think a lot of people assume that
Speaker 2: beavers live in their dams, but I think the better
Speaker 2: way to think about it is beavers construct dams in
Speaker 2: order to block waterways, which causes the area upstream of
Speaker 2: the dams to deepen and have a more lake like
Speaker 2: environment rather than a flowing river or stream. And then
Speaker 2: in that flooded area that is where they build the
Speaker 2: lodge they live in. So they sort of create a
Speaker 2: flooded area which can it can serve multiple purposes, one
Speaker 2: to house the lodge, but then also they can sort
Speaker 2: of dig out from there. I think you're about to
Speaker 2: mention something about this.
Speaker 1: Yeah, they're a lot like humans. Human beings do this
Speaker 1: with their modern technology. They come to say a dry
Speaker 1: desert environment or a swamp environment, and they're like, you know,
Speaker 1: what would go great here? What I would like for
Speaker 1: my purposes of living here. I'd love it to be
Speaker 1: just like a nice little park with some nice grass,
Speaker 1: you know, and maybe a few trees. I'm going to
Speaker 1: change everything so that it fits my needs. So the
Speaker 1: primary purpose for the beaver dam is to create a
Speaker 1: protective body of water for that lodge, making it even
Speaker 1: more difficult for predators to get at them. And even
Speaker 1: if predators were to get to them, they have that
Speaker 1: underwater escape route in the event of an attack. That's
Speaker 1: the that's the only way in and out now. It's
Speaker 1: worth noting, however, that especially in parts of Eurasia, beavers
Speaker 1: don't always have the same predator threat they once did.
Speaker 1: But they build anyway because no one told them not to.
Speaker 1: And also, more seriously, like, even though they are not
Speaker 1: predators now, I mean that's you know, any kind of
Speaker 1: evolutionary change would occur over a much vaster period of
Speaker 1: time than the removal of their predators.
Speaker 2: Amounts to right, So an environment full of say like
Speaker 2: gray wolves and bears may have shaped them. And even
Speaker 2: if there are many fewer of these predators than there
Speaker 2: once was, that they are still the animal made by
Speaker 2: that world.
Speaker 1: Right. For instance, they're still certainly nocturnal creatures. I mean
Speaker 1: they're also active, you know, dusk and dawn a little bit,
Speaker 1: but during the day proper, they're inside, they're resting, and
Speaker 1: part of that is to avoid predators. Now you mentioned earlier,
Speaker 1: Joe that you even just looking at videos, you can
Speaker 1: tell that they're more awkward on land than they are
Speaker 1: in the water. And that's of course another big important
Speaker 1: aspect of their damming of waterways, creating this sort of
Speaker 1: vast flood plain, like turning a stream going through a
Speaker 1: forest or something to this effect into kind of a
Speaker 1: flooded forest environment. This opens up speedy water routes back
Speaker 1: to their lodge. From perspective, feeding grounds.
Speaker 2: Yes, sort of the same way. You can imagine it
Speaker 2: like humans creating roads, like paved roads between say the
Speaker 2: farms that they work during the day and the houses
Speaker 2: they live in. But beavers would do this by instead
Speaker 2: creating flooded areas. Especially they can sort of like dig
Speaker 2: out channels along the bottom that the water from these
Speaker 2: flooded areas can run into, allowing them to have a
Speaker 2: sort of canals like roads made of water where they
Speaker 2: can move quickly, where they can move submerged, which is
Speaker 2: safer and better for them than trying to move awkwardly
Speaker 2: over land.
Speaker 1: Yeah. Now, in doing this, of course, they alter the
Speaker 1: ecosystem local ecosystem in a major way, opens up opportunities
Speaker 1: for various other organisms as well, and also discuss some
Speaker 1: of the potential downsides at least for some organisms in
Speaker 1: a bit. But at any rate, this cements the beaver's
Speaker 1: place as a keystone species. Beaver's just just completely change
Speaker 1: the immediate environment, produces more open water, higher water tables.
Speaker 1: And yeah, it's this entire system they have going for
Speaker 1: them here. It's just so fascinating. You can if you
Speaker 1: look online, you can find some some side profiles, some
Speaker 1: cutaways of what the lodge looks like, and it's pretty ingenious.
Speaker 1: It also serves as a place for them to store
Speaker 1: food and even provides refuge during frozen months. They don't
Speaker 1: hibernate properly, but they can hold up in there.
Speaker 2: One of the things I've read about is that they
Speaker 2: often can store lots of food, so they're vegetarians that
Speaker 2: eat actually like you know, parts of trees, vegetation from
Speaker 2: all around them, which they can keep stored in the
Speaker 2: world water underneath the pond created by their dams, and
Speaker 2: that's an interesting thing. They can raise the water level
Speaker 2: in order to help protect areas of food storage in
Speaker 2: the water for the winter, because by raising the water level,
Speaker 2: they create more area underneath that won't freeze over when
Speaker 2: the weather gets cold.
Speaker 1: Yeah, and these lodges and dams that they can even
Speaker 1: though the beavers themselves tend to only live about I
Speaker 1: think eight years max, a single lodge and dam can
Speaker 1: be maintained over generations, so the lodges may end up
Speaker 1: with like several stories to them, and the dams can
Speaker 1: get quite massive. There's an Alberta area dam that was
Speaker 1: built apparently in the nineteen seventies. Initially wasn't discovered till
Speaker 1: around two thousand and seven because it's just out in
Speaker 1: the middle of nowhere. It's not like in downtown Alberta.
Speaker 1: It's like out in the boonies and it's thought to
Speaker 1: be the world's largest beaver dam known beaver Dam anyway,
Speaker 1: covering a good half mile. There's actually an Alice Obscure
Speaker 1: article about it. If anyone's interested. Just look up world's
Speaker 1: largest beaver dam and you can see some like aerial photographs.
Speaker 2: You know, something interesting I was reading about was the
Speaker 2: role of beavers in maintaining ecosystem health by allowing for
Speaker 2: a greater diversity of different types of plant life to thrive.
Speaker 2: I think sort of in the same way that forest
Speaker 2: fires you might think of them as purely destructive. Of
Speaker 2: course they are destructive, but you know, forest fires occur
Speaker 2: naturally all the time, and when a forest burns, that
Speaker 2: creates sort of new opportunities for new types of plants
Speaker 2: and other life forms to thrive in a place that
Speaker 2: was once covered up by you know, a lot of
Speaker 2: tree canopy. So in the areas around beaver dams and lodges,
Speaker 2: they will clear out lots of the trees. They literally
Speaker 2: chew them down and they'll fall, and you know, the
Speaker 2: beavers will do what they will with them. But this
Speaker 2: creates all kinds of opportunities for other plants and other
Speaker 2: life forms that wouldn't normally thrive in the forest to
Speaker 2: have a shot.
Speaker 1: Yeah. Yeah, the paper that I came across was talking
Speaker 1: about sort of like the pros and cons. I have
Speaker 1: another one I'll get into about some of the potential benefits,
Speaker 1: but just to give you a full idea of sort
Speaker 1: of the rodent altered landscape we're talking about here, I
Speaker 1: was looking at a twenty fifteen paper published in IOP
Speaker 1: conference series, or presented in the IOP conference series Earth
Speaker 1: and Environmental Science. This one is This was by Raskova
Speaker 1: to Mina at All, and they talk about some of
Speaker 1: the positive and negative consequences, at least initially stressing some
Speaker 1: of the negatives maybe that are not at least instantly
Speaker 1: discussed as much. But you get soil overwetting obviously, because
Speaker 1: you're getting flooding occurrently it occurs. You also can have
Speaker 1: water stagnation that results in lack of oxygen, high carbon concentration,
Speaker 1: and the death of many aquatic organisms. And then the
Speaker 1: flooding can also cause vegetation death. But at the same time,
Speaker 1: the authors who are stressed that it can result in
Speaker 1: a rise in the biodiversity of water organisms. So you know,
Speaker 1: they're changing everything. They're changing the balance of the local ecosystem,
Speaker 1: and it's creating a lot of opportunities for new things,
Speaker 1: but it is also cutting things short for things that
Speaker 1: we're living there already. Now, a really interesting study that
Speaker 1: I came across this was a twenty twenty two Stanford
Speaker 1: study by Dewey at All published in Nature Communications, And
Speaker 1: in this paper they point out that beaver habitat ranges
Speaker 1: in the US are going to continue to widen with
Speaker 1: warming temperatures driven by climate change, but the benefits of
Speaker 1: their dam building will actually quote overshadow climate extremesquote. So
Speaker 1: this is not to say beaver dams will cancel out
Speaker 1: climate change or anything like that, but in some respects
Speaker 1: it kind of lessens the blow. Specifically as far as
Speaker 1: water quality in mountain watersheds are concerned. Dams can raise
Speaker 1: water levels upstream and divert water into soil and surrounding waterways,
Speaker 1: and this ends up sort of, this ends up like
Speaker 1: creating a robust filter system, a filtration system for excess
Speaker 1: nutrients and contaminants for the water before it passes on downstream.
Speaker 1: So today beaver's in North American eur Asia are both
Speaker 1: doing great. They have bounced back from near extinction due
Speaker 1: to hunting, and we may touch on some of that
Speaker 1: a little bit more in the next episode, but because
Speaker 1: there are a few different reasons that have driven beaver
Speaker 1: hunting over the years. But to go back to speaking
Speaker 1: of their construction of dams and their changing of the environment,
Speaker 1: there's another great illustration I came across by Nicholas de
Speaker 1: Fer who lives sixteen forty six through seventeen twenty, and
Speaker 1: this is just a small scene from a larger map.
Speaker 1: He was a French cartographer, so this is just you know,
Speaker 1: filling in some of the blank spaces, like we've discussed
Speaker 1: before on some of these older maps. But this illustration
Speaker 1: shows beavers at work. They are downing trees and they
Speaker 1: are dragging off the wood to build things. There are
Speaker 1: the beavers themselves look largely accurate. There may be a
Speaker 1: little more bear like, but the basic morphology is there.
Speaker 1: The main problems here are that, first of all, there's like,
Speaker 1: you know, one hundred beavers in this in this one image,
Speaker 1: like they're working as an army. And then also like
Speaker 1: clearly there wasn't a lot of detail on how they
Speaker 1: carry the wood, because the central beaver that you see
Speaker 1: is standing up in a bipedal posture with an armload
Speaker 1: of wood. Thrown over his shoulder like a human being.
Speaker 2: Yeah, yeah, like a Paul Bunyan carrying an axe.
Speaker 1: Yeah. But I like the spirit of industry that they
Speaker 1: captured here, despite some of the ridiculous details, and again
Speaker 1: a huge improvement over some illustrations from previous centuries.
Speaker 2: I wonder, is this one of the maps we looked
Speaker 2: at in our horror Vakay episodes where we were talking
Speaker 2: about maps with excessive illustrations.
Speaker 1: I don't believe it is. I looked at a bigger
Speaker 1: version of the map and I almost included it in
Speaker 1: our notes, and I don't think I had seen it before.
Speaker 1: It was a map that it's known as the beaver
Speaker 1: map and has to do with the locations of beavers
Speaker 1: because it has to do with the hunting of beavers,
Speaker 1: which again was quite a big industry for a while there,
Speaker 1: so big that it just about wiped them out. So
Speaker 1: the large semi aquatic rodents have come to flood the
Speaker 1: world and to remake it according to their designs. But
Speaker 1: the weirdness and the complexity doesn't stop there. Joe tell
Speaker 1: us a little bit about beaver society and about beaver
Speaker 1: tool use.
Speaker 2: Yeah, Rob, I think you found one of these papers first,
Speaker 2: and that's what started this whole. But I got lost
Speaker 2: on a going down a rabbit hole or maybe a
Speaker 2: beaver canal, trying to search out examples of possible tool
Speaker 2: use documented in beavers, and in fact, there are a
Speaker 2: few very interesting different observations corresponding to each of the
Speaker 2: extant species. Beavers clearly are an interesting type of animal
Speaker 2: to look at for signs of tool using intelligence, since
Speaker 2: they are masters of manipulating their environment through the dams
Speaker 2: and the lodges they build. Though I think it's interesting
Speaker 2: that nest building is often not typically thought of or
Speaker 2: not sort of front of mind as an example of
Speaker 2: tool use. And there are different examples that different zoologists
Speaker 2: or animal behavior experts will use to try to define
Speaker 2: tool use. So in the papers I was looking at,
Speaker 2: a few different standards were cited. One is a definition
Speaker 2: of tool use by a researcher named Alcock, who says
Speaker 2: it is quote the manipulation of an inanimate object that
Speaker 2: improves the organism's efficiency in altering the position or form
Speaker 2: of some other object. So, you know, using an inanimate
Speaker 2: object from the environment to better alter the former position
Speaker 2: of something else. Another definition I've found cited. This is
Speaker 2: from Beck in nineteen eighty quote the external employment of
Speaker 2: an unattached environmental object to alter more efficiently the form, position,
Speaker 2: or condition of another object, another organism, or the user itself,
Speaker 2: when the user holds or carries the tool during or
Speaker 2: just prior to use, and is responsible for the proper
Speaker 2: and effective orientation of the tool. Now, I appreciate all
Speaker 2: of the conditions on that, because I think it is
Speaker 2: important for people to be specific about what they're talking
Speaker 2: about when they look for examples of tool use. But
Speaker 2: I also wonder, once you're specifying that many conditions, is
Speaker 2: the category of tool use becoming more or like a
Speaker 2: function of the definition you lay out than than a
Speaker 2: fundamentally different type of activity itself than some other activity
Speaker 2: that that wouldn't quite fit this definition.
Speaker 1: Yeah, I mean, and sometimes we can almost get too
Speaker 1: hung up, I think, on the on the the idea
Speaker 1: of tool use and the definition of tool use, because
Speaker 1: we'll look at the most complicated burden, nest or bower
Speaker 1: that you can imagine and will be like, well, it's intricate,
Speaker 1: it's amazing, it's beautiful. But have you seen this monkey
Speaker 1: stabbing a smaller monkey with a stick. You know, it's
Speaker 1: you know, you know, it can almost you can almost
Speaker 1: set it up as this this thing that is the
Speaker 1: thing that we do. You know, that is a very
Speaker 1: there's something very human about tool use, and you know,
Speaker 1: obviously a huge, huge aspect of human life and human development.
Speaker 1: But but yeah, it's it seems like at times a
Speaker 1: lot of extra mental gymnastics is it has to be,
Speaker 1: it has to be utilized in order to even discuss it.
Speaker 2: So I'm not going to get super hung up on
Speaker 2: definition of tool use or what really counts as tool
Speaker 2: use today. We've talked about some of those debates in
Speaker 2: plenty of episodes in the past. Instead, I'm just going
Speaker 2: to talk about some studies describing specific behaviors, and you
Speaker 2: can make up your own mind about whether it seems
Speaker 2: like tool use to you. So the first thing I
Speaker 2: want to talk about is an older observation. It's older
Speaker 2: than either of the two papers that I'm going to
Speaker 2: discuss here, but it's cited in the first of them,
Speaker 2: and I'll get to that paper itself in a second.
Speaker 2: But the observation is that a researcher named Georgio Pilleri
Speaker 2: observed something interesting while studying two captive beavers at the
Speaker 2: Burn Brain Anatomy Institute in nineteen eighty three. So the
Speaker 2: beavers were living in a concrete pool that was supplied
Speaker 2: with a constant flow of fresh water, and overflow of
Speaker 2: this pool was routed away through a series of three
Speaker 2: drain holes, each zero point eight centimeters in diameters, so
Speaker 2: little holes in. The beavers had been given a supply
Speaker 2: of sticks and twigs to do what they wanted with,
Speaker 2: and for some reason, what they did is they selected
Speaker 2: and cut three sticks from their supply to the exact
Speaker 2: dimensions needed to plug the tiny drain holes that where
Speaker 2: water drained away from their pool. And this completely stopped
Speaker 2: the flow of water away from the pool. Now what's
Speaker 2: going on here? At first, it was kind of hard
Speaker 2: for me to believe this would be fully intentional behavior,
Speaker 2: as in, like the beavers understood that they were plugging
Speaker 2: the drains to stop the flow of water from their enclosure.
Speaker 2: But then I thought, you know, I guess I wouldn't
Speaker 2: be surprised if beavers have like a sense for detecting
Speaker 2: gaps in dams and plugging them, Like maybe they're good
Speaker 2: at sensing. My first instinct was maybe they sense like
Speaker 2: the delta pee. You know, the difference in pressure, like
Speaker 2: when water from a large pool is flowing out of
Speaker 2: a small piper hole and you could feel that pressure
Speaker 2: that would like get your hands stuck to the hole
Speaker 2: if you held it there, or which in larger scenarios
Speaker 2: can be of a great danger to divers. You know,
Speaker 2: you don't want to go near like the intake hole
Speaker 2: at a dam, if you're diving near it. I thought
Speaker 2: maybe they sense the delta pee, and so they sense
Speaker 2: that and they naturally want to plug it up, But
Speaker 2: I didn't know. However, I then sort of came across
Speaker 2: an answer. So I was watching a segment on North
Speaker 2: American beavers from BBC Earth narrated by David Attenborough, and
Speaker 2: this documentary segment captured a scene of beavers finding a
Speaker 2: leak in their dam and then getting right to work
Speaker 2: retrieving wood, vegetation and clumps of sediment down from the
Speaker 2: bottom of the pond to plug up the leak in
Speaker 2: the dam where water was running over the top. And Attenborough,
Speaker 2: in this documentary segment narrates that beavers are thought to
Speaker 2: detect these leaks by hearing the sound of trickling water
Speaker 2: and when they do, they begin repair work almost immediately.
Speaker 2: It seems to be fastidious, almost compulsive. This compulsive desire
Speaker 2: to fix the holes when they hear the water trickling,
Speaker 2: and this would make the drain plugging behavior in the
Speaker 2: concrete enclosure in the eighties make a lot more sense.
Speaker 2: So I decided to look into this further to see
Speaker 2: if this was indeed true to some degree. It seems
Speaker 2: it is, and so I didn't have time. This was
Speaker 2: soon before we started recording. I didn't have time to
Speaker 2: find the primary reference on this, but I did find
Speaker 2: a good twenty fifteen Gizmoto blog post by Esther inglis
Speaker 2: Arkell writing up summarizing the research of a Swedish zoologist
Speaker 2: named Lars Wilson who studied beavers back in the nineteen sixties,
Speaker 2: and according to the summary, Lars Wilson found that dam
Speaker 2: building was instinctual rather than learned, and the way Wilson
Speaker 2: identified with this was that if you took young beavers
Speaker 2: and you separated them from their parents at birth, they
Speaker 2: would still build dams basically the same way, using the
Speaker 2: same techniques as their parents, even though they were clearly
Speaker 2: not having the opportunity to be taught to do that.
Speaker 2: So it seems based on that at least this is
Speaker 2: probably a routine behavior. It's based on beaver DNA. They
Speaker 2: don't have to be taught. But Wilson also found that
Speaker 2: beavers didn't always build dams. In environments with still water
Speaker 2: or only very gently moving water, dam building was not
Speaker 2: a priority. The beavers would just maybe they like dig
Speaker 2: a hole in the mud and just chill there, you know,
Speaker 2: they just wouldn't build. And so by manipulating different variables,
Speaker 2: Wilson identified the sound of trickling water as the primary
Speaker 2: trigger for dam building, even to the point of a
Speaker 2: discovery that this was the part I found most fascinating.
Speaker 2: If you put a speaker in the beaver's enclosure and
Speaker 2: you played the sound of trickling water through it, the
Speaker 2: beavers would go to the speaker and start building on
Speaker 2: top of it. They would start piling up sticks and
Speaker 2: mud and branches over the speaker playing the sounds. They
Speaker 2: were trying to plug the speaker to make it stop leaking.
Speaker 1: Oh my goodness.
Speaker 2: Wilson also found that if outflow pipes, so you had
Speaker 2: a place where there was actually water leading away from
Speaker 2: the pool, but you carefully designed the pipe so that
Speaker 2: they made no noise, the beavers would not be able
Speaker 2: to find and cover them. So this might lead you
Speaker 2: to think, okay, so like the louder the rushing of
Speaker 2: the water, the more beavers want to make a damn there.
Speaker 2: But it also seems like it's not quite that simple,
Speaker 2: because I was reading a news article from the Harvard
Speaker 2: Graduate School of the Arts and Sciences called Damned If
Speaker 2: They Do by Paul Massari. This article profiles the research
Speaker 2: of an environmental engineer named Jordan Kennedy who has done
Speaker 2: research on beavers and their dam building practices and the
Speaker 2: environmental effects thereof. And Kennedy says that it can't just
Speaker 2: be about the like the magnitude of sound of moving water,
Speaker 2: or beavers would be trying to build dams across Niagara Falls,
Speaker 2: you know, just like loud, violent, rushing waters where building
Speaker 2: would be totally impractical. So instead, there's got to be
Speaker 2: a kind of Goldilocks zone for dam construction, something that
Speaker 2: the beavers naturally detect that allows them to know, Okay,
Speaker 2: this is about the right amount of flow to try
Speaker 2: to dam up.
Speaker 1: Yeah, yeah, damming up Niagara Falls, like obviously, that would
Speaker 1: be great like, that's kind of like the beaver fan fiction.
Speaker 1: That's the pipe drain, But is it practical. No, you
Speaker 1: need to have that just the right environment that can
Speaker 1: then be manipulated to make the ideal environment for the beaver.
Speaker 2: Right, So, the author of this article writes, quote, the
Speaker 2: water in a beaver's habitat needs to be a certain depth,
Speaker 2: for instance, to keep a food cache from freezing to
Speaker 2: the bottom in winter and to enable them to evade predators.
Speaker 2: The plants that beavers prefer to eat flourish best when
Speaker 2: water flows at a certain velocity. So you're looking for
Speaker 2: this goldilocks zone, an area of a certain amount of
Speaker 2: water flow, maybe a certain narrowness of the channel or
Speaker 2: certain depth of the channel, and that's the place where
Speaker 2: you want to dam it up. And beavers apparently they
Speaker 2: locate that. A big part of the sense data informing
Speaker 2: them of that area appears to be sound. Maybe maybe
Speaker 2: the overwhelming part of it is sound, but there may
Speaker 2: be other cues as well, and so I don't know.
Speaker 2: I thought this was so interesting, and I'm just trying
Speaker 2: to imagine what it's like to be a beaver, to
Speaker 2: have this powerful instinctual drive to plug leaks. So imagine
Speaker 2: the same kind of base level instinctual drive that humans
Speaker 2: might have for sex, or for food, or to care
Speaker 2: for children, all the like the most powerful drives in
Speaker 2: our brains. But there's a drive like that to hunt
Speaker 2: down the source of anything that sounds like trickling water
Speaker 2: and to just plug it with junk. You know, I
Speaker 2: don't know. That's like, that's another that's another type of
Speaker 2: mind experience, a relationship to the environment.
Speaker 1: Wow wow, yeah, Like what would yeah, how would like
Speaker 1: we can't help but extrapolate that into like a human
Speaker 1: like intellect and human like culture, Like what would advance
Speaker 1: beaver civilization be? Like would they actually go after like
Speaker 1: complete inundation, like a complete flooding situation, the destruction of
Speaker 1: all naturally occurring waterfalls, or would they just kind of
Speaker 1: dream about it? Or what would their TV shows be?
Speaker 1: Would it just be like countless channels of leak plugging
Speaker 1: and so forth.
Speaker 2: The speaver thought she had it all, but then she
Speaker 2: heard the trickle and couldn't find it searching, Like all
Speaker 2: dramas begin with the conflict of hearing a trickle.
Speaker 1: That's the call to adventure.
Speaker 2: Yeah, but anyway, all that stuff I just read about
Speaker 2: got kicked off because I was reading that anecdote about
Speaker 2: the findings of Giorgio Pillari in nineteen eighty three, which
Speaker 2: was cited in a paper by D. M. Barnes called
Speaker 2: possible tool use by beavers cast Or canadensis in a
Speaker 2: Northern Ontario watershed published in the Canadian Field Naturalist in
Speaker 2: two thousand and five. So this is one of the
Speaker 2: main two papers I was looking at about possible cases
Speaker 2: of tool use in beaver's Barnes says that this report
Speaker 2: is based on evidence relating to the North American beaver
Speaker 2: that's Castor canadensis at a remote damn site in the
Speaker 2: Chapleaux Crown Game Preserve in northern Ontario. The author says,
Speaker 2: at this location they found a clump of willow stems,
Speaker 2: so like little small tree trunks that had been cut
Speaker 2: by beavers. But the fascinating thing was they were cut
Speaker 2: at the extraordinary height of approximately one meter off the ground.
Speaker 2: Beavers are not that tall normally, these beavers cut at
Speaker 2: an average height of about thirty centimeters, so the beavers
Speaker 2: were chomping off these willow trees at three times the
Speaker 2: normal height they could reach with their teeth. Barnes writes, quote,
Speaker 2: I made a careful examination of the area and found
Speaker 2: that there was no apparent way the beavers could have
Speaker 2: cut the stems at such a height. When I studied
Speaker 2: the willow clump more closely, I noted that there was
Speaker 2: a freshly cut willow stem approximately twelve centimeters in diameter,
Speaker 2: leaning against the main stem of the willow clump. Its
Speaker 2: approximate angle was forty five degrees. In addition, I observed
Speaker 2: cutting at both ends of the leaning willow segment, and
Speaker 2: then there was a There was a photo accompanying this
Speaker 2: in the article. Now, at first the author thought that, okay,
Speaker 2: so this is a log propped up forty five degrees
Speaker 2: against the tree that is cut off very tall. The
Speaker 2: author thought maybe this log there had simply fallen that way.
Speaker 2: I don't know, it's something that the beaver cut and
Speaker 2: then it fell. But that's impossible on further examination, because
Speaker 2: the log was clearly from a different tree than the
Speaker 2: stem it was leaning against, like there was different bark
Speaker 2: texture and color and so forth, and its position just
Speaker 2: did not seem plausible if it had fallen from above.
Speaker 2: Another possibility the author considered was that these willow trunks
Speaker 2: had been foraged while there was heavy snow on the
Speaker 2: ground in the winter. So maybe the beavers were able
Speaker 2: to reach a meter up the trunks of these trees
Speaker 2: by crawling around on top of the snow. Okay, but
Speaker 2: the author things that's really unlikely. Given the position of
Speaker 2: the willow clump relative to the beaver dam and lodge
Speaker 2: and its entrance and exit. It seems it would have
Speaker 2: required a major overland journey by the beavers on the
Speaker 2: top of the snow in the winter at a time
Speaker 2: where this just would not fit with their normal behavior. Instead,
Speaker 2: the author suggests that maybe what happened here is the
Speaker 2: beaver used a prop. The beaver used a piece of
Speaker 2: a log that it had cut off at both ends
Speaker 2: and propped it up against the base of the trees,
Speaker 2: and then climbed up that and was able to chew
Speaker 2: off the willow stems at an upper level rather than
Speaker 2: a lower level. Now, why would this even be beneficial?
Speaker 2: The author says this would be probably to reduce foraging time.
Speaker 2: So the longer you forage number one, the more thermal
Speaker 2: stress you're exposed to not being the right temperature. But
Speaker 2: more importantly, the longer you are exposed to predation. Apparently
Speaker 2: beavers do not like to spend a lot of time
Speaker 2: out on the ground out of the water, so they
Speaker 2: are trying to hustle as fast as they can whenever
Speaker 2: they're out there cutting, and in this case, apparently using
Speaker 2: a cut stem to climb up the willow trunks to
Speaker 2: access a higher up part of the tree to chew
Speaker 2: through would have meant that they had to spend less
Speaker 2: time chewing and less time cutting all right.
Speaker 1: Like a little bit higher they just it's gonna be less,
Speaker 1: it's gonna be a narrow or bit of wood to
Speaker 1: shoot through.
Speaker 2: That's what I assumed. It didn't specify exactly why cutting
Speaker 2: higher up was reduced foraging time, but that was my interpretation.
Speaker 1: I could be wrong, and that's why they potentially could
Speaker 1: be using essentially a beaver ladder, a beaver bit of scaffolding.
Speaker 2: Right, But we don't know. This is just one observation.
Speaker 2: And also they didn't see them doing it. They just
Speaker 2: found this strange piece of scaffolding there later.
Speaker 1: Yeah, more mysteries related to I mean, I guess this
Speaker 1: is kind of cutting into some of the mysteries involved
Speaker 1: in these wildly inaccurate depictions of beavers is that these
Speaker 1: are creatures that live often in very rural situations, far
Speaker 1: from human activity. They're probably doing it at night, and
Speaker 1: they're spending as a little time necessary doing it out
Speaker 1: where other eyes could see them.
Speaker 2: Right, okay. Second paper I came across alleging possible tool
Speaker 2: use behaviors by This is called tool use in a
Speaker 2: display behavior by Eurasian beavers or castor fiber in the
Speaker 2: journal Animal Cognition by Thompson at All in two thousand
Speaker 2: and seven. So here the authors write that documentation of
Speaker 2: tool use is relatively rare in rodents, and prior to
Speaker 2: this paper there were no documented cases they knew of
Speaker 2: of tools being used by rodents in what are called
Speaker 2: agonistic displays. Now, agonistic is a word used in the
Speaker 2: study of animal behavior to describe conflict or fighting. So
Speaker 2: an agonistic behavior is not necessarily fighting itself, but also
Speaker 2: could include social behaviors related to fighting. So these would
Speaker 2: include threat displays trying to, you know, look big or
Speaker 2: otherwise intimidate another animal, displays of aggression, as well as
Speaker 2: things like submission or retreat behavior. The authors of this
Speaker 2: paper say that in their field observations of the Eurasian beaver.
Speaker 2: They witnessed the behavior that they call stick display, which
Speaker 2: they interpreted as an agonistic display behavior. And what this
Speaker 2: consisted of is beaver would go pick up an object,
Speaker 2: usually a stick, whenever a stick was available, and then
Speaker 2: it would rise up on its hind legs and then
Speaker 2: move the upper body rapidly up and down while holding
Speaker 2: the stick or other object in its mouth and front paws.
Speaker 2: And Rabbi attached a picture for you to look at.
Speaker 2: They had a photo of this. In this photo of
Speaker 2: the beaver is in the shallow part of a waterway.
Speaker 2: It's standing up on its back legs. It's kind of
Speaker 2: I don't know how to just it's kind of like
Speaker 2: roaring posture. But it's got a big old stick in
Speaker 2: its mouth, and it's gripping the stick with its two
Speaker 2: four paws, and the water is splashing all around as
Speaker 2: the stick I guess, rapidly dips in and out.
Speaker 1: It's impressive and it's frankly a little intimidating, this beaver saying, behold,
Speaker 1: look at the feats of strength. I am capable of.
Speaker 2: So several observations about this behavior. First of all, they say,
Speaker 2: beaver's only picked up these display sticks or other objects
Speaker 2: at the same location where they were used, and they
Speaker 2: were never seen modifying the objects, so it wouldn't It
Speaker 2: wasn't like they would carry a stick around and then
Speaker 2: use it in a different location or modify the stick
Speaker 2: in any way.
Speaker 1: So, for instance, compare it to like human tool use
Speaker 1: that we've discussed in the past rocks. This would not
Speaker 1: be on the level of picking out favored rocks for
Speaker 1: throwing at other humans, polishing them, changing them, etc. This
Speaker 1: would be more on the level of when threatened, you
Speaker 1: might look down, grab a rock and use it. Though
Speaker 1: of course, in this case, the beavers are not hitting
Speaker 1: each other with the sticks allegedly, the hypothesis here is
Speaker 1: that they're using them as a pure defensive display.
Speaker 2: Right. Second thing, This often happened in shallow water, so
Speaker 2: the shaking of the stick would cause splashing in the
Speaker 2: surrounding water, but occasionally it also took place on dry land,
Speaker 2: such as in weeds, where there was no significant sound produced.
Speaker 2: So the authors think because it took place in both
Speaker 2: scenarios and when it was on dry land it didn't
Speaker 2: really make a noise, they think it is primarily a
Speaker 2: visual signal. An important bit of context is that Eurasian
Speaker 2: beavers are territorial. They live in family groups with usually
Speaker 2: a dominant breeding pair and then assorted offspring of that
Speaker 2: breeding pair. And they defend the borders of their territory
Speaker 2: from encroachment by other beavers. So they mark their territory
Speaker 2: by scent. This is done with secretions from the anal
Speaker 2: glands or castorium. Which castorium, I believe, we'll talk about
Speaker 2: more later in the series in part two allegedly smells
Speaker 2: like vanilla, but we'll come back. When rival beavers come
Speaker 2: into a family group's territory, the home turf beavers will
Speaker 2: react first of all with tail slapping. Rob you mentioned this.
Speaker 2: This is a loud signal that beavers make by repeatedly
Speaker 2: smacking the water surface with their tails. This is also
Speaker 2: used to alert members of the family group when a
Speaker 2: predator is cited. They also respond to unwelcome presence by
Speaker 2: visual displays or sometimes with actual fighting, though physical fights
Speaker 2: are relatively rare. The observations carried out in this study
Speaker 2: were conducted on wild Eurasian beavers in southeast Telemark, Norway. Overall,
Speaker 2: the researchers observed one hundred and thirty one cases of
Speaker 2: stick display behavior that met the criteria for inclusion in
Speaker 2: their study by four adult males, two adult females, and
Speaker 2: five unidentified animals. However, it seems that some individual beavers
Speaker 2: engaged in stick displays far more than the others.
Speaker 1: Quote.
Speaker 2: It was clear from our observations that one female beer
Speaker 2: Git and one male Froda were the main performers, with
Speaker 2: a contribution of fifty one point nine percent and thirty
Speaker 2: five point nine percent, respectively, of the total number of
Speaker 2: stick displays observed. So what does that add up to.
Speaker 2: It's like eighty seven percent of stick displays were from
Speaker 2: two beavers.
Speaker 1: Wow, go Froda.
Speaker 2: The real champion is beer Get here. She's got more
Speaker 2: than half of them just under her belt.
Speaker 1: Yeah yeah, I mean really, beer Get needs to get
Speaker 1: get most of the credit here from Froda doing pretty
Speaker 1: well as well.
Speaker 2: So they say, stick displays happened almost exclusively at the
Speaker 2: borders of beaver family group territory, and most displays appeared
Speaker 2: to be directed at rivals. The displays were often preceded
Speaker 2: by scent marking, so this kind of suggests it probably
Speaker 2: is being used as an agonistic display. However, this behavior,
Speaker 2: while common in the groups observed in this study, is
Speaker 2: not necessarily generalizable to the total world population of these beavers.
Speaker 2: It has not really been observed in beaver's generally across
Speaker 2: the full range, suggesting it may be specific to certain populations.
Speaker 1: Wow, like even like some sort of like localized beaver culture.
Speaker 2: Yeah, maybe apparently something. At the time of the study,
Speaker 2: the author said there were some isolated reports of similar
Speaker 2: behavior in a few North American beavers, but not most,
Speaker 2: and it was not found in all Eurasian beavers either.
Speaker 2: So the authors argue that stick displays might be especially
Speaker 2: favored in high pressure situations. From reading their description of
Speaker 2: the area, it seems like the groups observed in this
Speaker 2: study might be in especially crowded beaver territory, where like,
Speaker 2: you know, the areas around different family dams and lodge
Speaker 2: sites are sort of all butting up against one another.
Speaker 2: They also observed higher rates of stick displays in springtime,
Speaker 2: meaning it's possible it could have some association with breeding.
Speaker 2: But if the stick shaking is a genuine agonistic display behavior,
Speaker 2: the evolutionary purpose would probably be to convey honest information
Speaker 2: about the beaver's size and strength, so it's like, I'm
Speaker 2: big and strong. Look at how I can shake this stick.
Speaker 2: You don't want to bother actually getting into a fight
Speaker 2: with me, right, we don't have to do this.
Speaker 1: I like these sort of levels of communication that seem
Speaker 1: to exist between beaver groups here. You know, it's like,
Speaker 1: at the end of the day, all beavers really want
Speaker 1: to do is build things and plug holes. Uh. You
Speaker 1: know they have they have a lot of hole plugging
Speaker 1: to do. They have they have a lot of work
Speaker 1: to accomplish. They don't really have time to get into
Speaker 1: these fights. These fights are just would be destructive. Uh
Speaker 1: So instead, let's just make sure that we're very clear
Speaker 1: about how everyone feels about these these border scenarios, and uh,
Speaker 1: if need be, let me just show you, give you
Speaker 1: a taste of what could happen. Just look at this
Speaker 1: stick lifting ability here.
Speaker 2: The neighbors are getting nosy and beerget shakes a branch
Speaker 2: and it's like, no, don't make me do it. Don't
Speaker 2: make me do it. And it seems most of the
Speaker 2: time they're like, Okay, I won't make you do it. Bergeit, man.
Speaker 2: I think we've got to be out of time for
Speaker 2: for part one of Beaver's here right, But there will
Speaker 2: be more.
Speaker 1: Yeah, in the next episode, we're gonna we're gonna get
Speaker 1: back to that idea, that that false idea of beaver
Speaker 1: whilst being hunted deciding to chew their own testicles off
Speaker 1: again that you see various examples of, particularly from like
Speaker 1: illuminated manuscripts and so forth and bestiaries. We'll come back
Speaker 1: and to discuss that, plus who knows what else we'll
Speaker 1: uncover about beavers in our research. In the meantime, we'd
Speaker 1: love to hear from everyone out there if you have
Speaker 1: any especially since a lot of times we do these
Speaker 1: Tuesdays to Thursday. This one's going to be a Thursday
Speaker 1: to Tuesday, so who knows, you might be able to
Speaker 1: get some really core beaver facts and beaver experiences into
Speaker 1: us before we record the next episode. You know something
Speaker 1: you've picked up somewhere or just you know, accounts of
Speaker 1: observing beavers in the wild. I'd love to hear about that. So,
Speaker 1: whatever your feedback, whatever your thoughts, share them with us.
Speaker 1: We would love to hear from you. Just a reminder
Speaker 1: that Stuffed to Blow Your Mind is a science podcast
Speaker 1: with core episodes on Tuesdays and Thursdays, So look for
Speaker 1: those in the Stuff to Blow Your Mind podcast feed
Speaker 1: wherever you get your podcasts. On Mondays we do a
Speaker 1: listener mail episode. On Wednesday's do a short form artifact
Speaker 1: or monster fact episode. I know sometimes people say I
Speaker 1: wish they were longer. Well, they're short. That's part of
Speaker 1: how it works. But occasionally we're gonna put out We're
Speaker 1: going to continue to experiment, experiment with putting out omnibus
Speaker 1: episodes that may take up like multiple related monster facts
Speaker 1: or artifacts, and put them out so periodically you'll get
Speaker 1: a longer one in there as well. So yeah, let
Speaker 1: us know if you're liking that, and we can keep
Speaker 1: doing it. Oh and then on Fridays we set aside
Speaker 1: most serious concerns to just talk about a weird movie
Speaker 1: on Weird House Cinema.
Speaker 2: Huge thanks to our audio producer JJ Posway. If you
Speaker 2: would like to get in touch with us with feedback
Speaker 2: on this episode or any other, to suggest a topic
Speaker 2: for the future, or just to say hello, you can
Speaker 2: email us at contact at stuff to Blow your Mind
Speaker 2: dot com.
Speaker 3: Stuff to Blow Your Mind is production of iHeartRadio. For
Speaker 3: more podcasts from my Heart Radio, visit the iHeartRadio app
Speaker 3: Apple Podcasts or wherever you're listening to your favorite shows,