Speaker 1: Welcome to Stuff to Blow Your Mind, the production of iHeartRadio.
Speaker 2: Hey you welcome to Stuff to Blow your Mind. My
Speaker 2: name is Robert Lamb, and I'm Joe McCormick. We've covered
Speaker 2: numerous examples of this before. But obviously, in days before
Speaker 2: photography and videography, one had to depend on illustrations and
Speaker 2: written descriptions to convey the reality of an organism, you know,
Speaker 2: be it a bird or a fish, what have you.
Speaker 2: But this is especially true for creatures that lived in
Speaker 2: lands beyond your direct experience. You know, what are the
Speaker 2: what are the mammals, what are the birds? Like on
Speaker 2: another continent. Well, you have to send people out in
Speaker 2: the world. They can, you know, to a certain extent.
Speaker 2: They can bring specimens back. Certainly, they can bring parts
Speaker 2: of specimens back, but it's those illo in some cases.
Speaker 2: But it's those illustrations that really bring things alive. Now,
Speaker 2: certainly there are some fine examples of naturalist illustration out there,
Speaker 2: especially from recent centuries. I mean there's some gorgeous, like
Speaker 2: you say, like Audubond illustrations and paintings that sort of thing.
Speaker 2: But there are also countless examples, and we've touched on
Speaker 2: these before in the show of rougher drawings, drawings that
Speaker 2: feel like, you know, there's been a game of telephone
Speaker 2: at play. And this is especially the case for examples
Speaker 2: found in various bestiaries and medieval manuscripts, among other places.
Speaker 2: And when we think of such misconstrued animals, you know,
Speaker 2: what do we tend to think about? You know, we
Speaker 2: think about the rhino, We think about the lion, the whale,
Speaker 2: the elephant, you know, great animals, apex, predators, and megafauna.
Speaker 2: But in this episode, in the next episode, at the
Speaker 2: very least, we're going to get into another creature that
Speaker 2: has also experienced extreme inaccuracy in historic illustration, and that
Speaker 2: is a common beaver. Based on just some of the
Speaker 2: images we've been looking at, a beaver might well be
Speaker 2: a kind of strange dog or a pig, with perhaps
Speaker 2: a fish tail on its body and a real hybrid
Speaker 2: feeling like it is, almost like it's a strange like
Speaker 2: dog mermaid. It might be in almost all respects a deer,
Speaker 2: like a creature with long legs and hooves, And it
Speaker 2: may also look like a strange and confused rodent with
Speaker 2: a great button seam running down its chest. It may
Speaker 2: even look like a weirdly serpentine lion.
Speaker 3: So Rob has been sharing medieval and Renaissance illustrations of
Speaker 3: beavers with me for a couple of days now, and
Speaker 3: I really do love all of them, but I do
Speaker 3: think the one I like the most is the one
Speaker 3: that's just straight up a deer with hooves, except it
Speaker 3: has razor blades for teeth, just like the rectangular blades.
Speaker 2: Yeah, yeah, this one. I had to go deeper on
Speaker 2: this one because I was it initially came up in
Speaker 2: an image search, and you know, I think it was
Speaker 2: maybe on a Pinterest or something. I was like, I
Speaker 2: can't trust this, but I eventually looked it up in
Speaker 2: the catalog of illuminated manuscripts and it is a Northern
Speaker 2: Italian illustration from somewhere around the year fourteen forty, and yeah,
Speaker 2: it just looks like a It is labeled as a beaver,
Speaker 2: but it is in all respects of deer. So I
Speaker 2: was just really astounded, like here, especially as an image,
Speaker 2: that it not only gets the form wrong regarding the
Speaker 2: target organism, it gets everything about like the energy of
Speaker 2: the creature wrong, you know, cause it's it's one thing
Speaker 2: if you have a depiction of a rhino. That okay,
Speaker 2: it's like a big armor plated thing with four legs.
Speaker 2: It's like, all right, I mean, that's it's an extravagant
Speaker 2: version of the truth. But this it's like, how wrong
Speaker 2: did this game of telephone go?
Speaker 3: Right? With the right you like, with deerors rhinoceros, you
Speaker 3: can see that beginning as a rhinoceros but with embellishments, yes,
Speaker 3: But with the beaver, it's like, oh, I'm sorry, did
Speaker 3: you say beaver? I thought you asked for a depiction
Speaker 3: of a lion with a snake neck biting its own genitals.
Speaker 2: That's right, because and this is this is something we'll
Speaker 2: probably get into mostly in the next episode, but there
Speaker 2: is this pervasive myth that existed for a very long
Speaker 2: time that when pursued by hunters, a male beaver would
Speaker 2: chew off its own testicles. And so many of these images.
Speaker 2: Be your creature more dog or catlike or or or
Speaker 2: actually just a deer with razor sharp teeth, it is
Speaker 2: often depicted g nine at its testicles. That at least
Speaker 2: we have some answers for in the next episode where
Speaker 2: that idea comes from and why it's so pervasive.
Speaker 3: Right, So you've got to stick around for next time
Speaker 3: to hear that.
Speaker 2: Yeah, so let's let's start with what we know. Let's
Speaker 2: start with the reality. We're gonna start by talking about
Speaker 2: just basic beaver anatomy and behavior. And I probably don't
Speaker 2: have to tell most listeners out there what a beaver
Speaker 2: looks like. I mean, for starters, like, we have images
Speaker 2: all over the place of them, we have documentary footage.
Speaker 2: Many of you can go and see a live beaver
Speaker 2: at least in some sort of like a zoo environment,
Speaker 2: or you have seen them in the past. But on
Speaker 2: the other side of the coin, it's like, I still
Speaker 2: kind of have to tell you what a beaver looks
Speaker 2: like because the beaver is kind of in the same
Speaker 2: category as the spouting whale, as we discussed in some
Speaker 2: of our recent whale episodes, that's particularly the ones on
Speaker 2: spouting and spouts. Because despite all this access to actual,
Speaker 2: solid documentary footage of the beaver, we still have this
Speaker 2: rich history of cartoon depictions of beavers that inevitably cloud
Speaker 2: our understanding of the creatures.
Speaker 3: I mean, I think you get a fairly accurate mental
Speaker 3: picture if you just cross a squirrel with a grizzly bear.
Speaker 3: You know, you mash those two up your most of
Speaker 3: the way there. But while that does get you sort
Speaker 3: of the shape the outline, right, that does not tell
Speaker 3: you everything you need to know about beaver's. Beavers are
Speaker 3: much stranger and more beautiful than I realized.
Speaker 4: Yeah.
Speaker 2: Yeah, there's a lot of weird and wonderful aspects to
Speaker 2: their morphology, to their behavior, and a lot of this
Speaker 2: is stuff that our popular conceptions of the beaver don't
Speaker 2: get into. I mean, you know, they do get some
Speaker 2: of the things right. You know, the basic shape of
Speaker 2: the beaver is far better in cartoon than it is
Speaker 2: in many of these eliminated manuscripts. You know, some things
Speaker 2: hold up. Obviously, beavers are not going to sell you
Speaker 2: out to the White Witch. That's absolutely true. So C. S.
Speaker 2: Lewis was right on that count, even if he got
Speaker 2: the whole diet of the beaver wrong, because in Narnia,
Speaker 2: apparently beavers like to eat fish and chips. That's not
Speaker 2: happening in the actual natural world.
Speaker 3: On the other hand, I will say, there is the
Speaker 3: kind of food and organism usually seeks out to eat
Speaker 3: in its environment, versus what an animal will eat if
Speaker 3: given the opportunity. I kind of wonder. I feel like
Speaker 3: if you gave a beaver a basket chips and some
Speaker 3: malt vinegar, I don't know they might get into that.
Speaker 2: All right, Well, let's start with the basics here. So
Speaker 2: beavers are rodents and are in fact the second largest
Speaker 2: extant rodent, surpassed only by the mighty capybara. Beavers can
Speaker 2: weigh up to fifty kilograms or one hundred and ten pounds.
Speaker 2: There are two extant species of beaver. There's the North
Speaker 2: American beaver or Castor canadensis and the Eurasian beaver caste
Speaker 2: or fiber. But the Castoridae family includes some impressive extinct
Speaker 2: species as well. In fact, there were giant beavers that
Speaker 2: lived during the Pleistocene, reaching weights of up to one
Speaker 2: hundred and twenty five kilograms or two hundred and seventy
Speaker 2: six pounds, So that is more than twice as big
Speaker 2: as extant beavers, though I was reading they seem to
Speaker 2: have had smaller brains, among other morphological differences. But yeah,
Speaker 2: so they were bigger, and you know, maybe to some
Speaker 2: extent they didn't have to or at not yet developed
Speaker 2: these very impressive behaviors and abilities that we'll get into
Speaker 2: concerning modern beavers. Now, one note on these guys. They
Speaker 2: were still smaller than the fifteen hundred kilogram or thirty
Speaker 2: three hundred pound giant pacaranas of South America. Extant pacaranas
Speaker 2: only get up to like thirty three pounds or fifteen kilograms,
Speaker 2: and they can still be found in the western Amazonian
Speaker 2: River basin. But the giant ones they were pretty massive.
Speaker 2: A lot of rodents of unusual size in prehistory, all.
Speaker 3: Right, So no beavers today in that territory. But beavers
Speaker 3: can still get pretty chunky.
Speaker 2: That's right. Yeah, they're pretty big. And this is like
Speaker 2: a fact. I frequently forget that they're the second biggest rodent.
Speaker 2: The Caapi bear is easy to remember, but it's sometimes
Speaker 2: it's easy to forget who's coming in second. Now, it's
Speaker 2: extremely important to note that beavers are semi aquatic, having
Speaker 2: evolved to thrive in various freshwater habitats. So a number
Speaker 2: of the things we're going to be discussing about them
Speaker 2: lying up with their habitat. For instance, they can hold
Speaker 2: their breath for fifteen minutes. They have transparent third eyelids
Speaker 2: called micitating membranes to aid them in their swims much
Speaker 2: like manates. They also famously have long, flat, black tails.
Speaker 2: We know this from the cartoons obviously, and these aid
Speaker 2: them and they're swimming, but they can also use them
Speaker 2: to sound an alarm by slapping the water, slapping the
Speaker 2: surface of the water, and they also use them to
Speaker 2: balance when they're carrying wood or other loads across the ground.
Speaker 2: For any of you out there who watch a lot
Speaker 2: of animal videos on Instagram and so forth, you may
Speaker 2: have seen videos of adorable beavers carrying carrots around, and
Speaker 2: if you're not looking closely enough, you might think they're
Speaker 2: dragging their tails. But if you will look closely, you
Speaker 2: can see that the tail is off the ground and
Speaker 2: it's helping them balance.
Speaker 3: One of the things I've noticed about watching beavers try
Speaker 3: to move objects around is how much more gracefully they
Speaker 3: do it in the water than on the land. So
Speaker 3: these are semi aquatic mammals, but I don't know, it
Speaker 3: seems to me that the water is where they're really
Speaker 3: in their element. They can swim fast and gracefully, even
Speaker 3: carrying like an unwieldy branch that's kind of unbalanced or something.
Speaker 3: They do that all quite well in the water and
Speaker 3: then once you see them sort of toddling along across
Speaker 3: the dry land, it looks much more comical and awkward.
Speaker 2: Yeah, and this is going to be important to keep
Speaker 2: in mind when we talk about the amazing ways that
Speaker 2: they transform an environment to better fit their needs and desires.
Speaker 2: Oh but before we get into that, we of course
Speaker 2: have to talk about the teeth of the beaver. This
Speaker 2: is something that is generally an important part of cartoon
Speaker 2: imagery concerning the beaver. A lot of times cartoon beavers
Speaker 2: will speak with a kind of whistle in their voice,
Speaker 2: but we also tend to get it quite wrong.
Speaker 3: Okay, so I'm trying to picture the cartoon beaver. I
Speaker 3: think what we always see is an overbite with two
Speaker 3: kind of square shaped teeth grouped right together in the middle,
Speaker 3: like a person's front two teeth, but large and overlapping
Speaker 3: the bottom lip. Is that about it?
Speaker 2: Yeah? Yeah, pretty much.
Speaker 3: The truth is much more shocking.
Speaker 2: Yeah, yeah, they have these. You know, if you look
Speaker 2: at a skull of a beaver, it's pretty remarkable because
Speaker 2: it's like this, the really kind of exaggerated rodent skull
Speaker 2: with just incredible incisors, you know, with these two big
Speaker 2: shovel like teeth coming down from the top, two big
Speaker 2: shovel like teeth coming up from the bottom, and then
Speaker 2: the rest of the back teeth or much further back,
Speaker 2: you know, giving them some ample room to do the
Speaker 2: kind of a woodwork that they need to do with
Speaker 2: those chompers.
Speaker 3: The skull is a powerful bone hinge, and it's like
Speaker 3: it's like a kind of alien biotechnological set of bolt cutters,
Speaker 3: except the bolt cutters are orange teeth.
Speaker 2: That's right. The orange is key. This is something I
Speaker 2: will almost never see in like a cute c illustration
Speaker 2: or a cartoon depiction of a beaver. So, yeah, these
Speaker 2: teeth have thick layers of enamel which has this orange colorization.
Speaker 2: Because while other rodents boast magnesium enriched tooth enamel, beavers
Speaker 2: have iron enriched enamel. They're like, I mean, it's it's
Speaker 2: like something out of out of a comic book, right.
Speaker 2: The iron makes their teeth stronger against this the pure
Speaker 2: mechanical stress that they put them through. We should also
Speaker 2: note that these teeth continue to grow throughout their lives,
Speaker 2: to the point where they have to gnaw them down
Speaker 2: on trees to keep them down. But yeah, they're just
Speaker 2: super resilient, always growing, and they're also more resilient to
Speaker 2: acid as well based on their composition.
Speaker 3: Just some tough, rusty looking teeth.
Speaker 4: Yeah, yeah, the orange is really quite shyy.
Speaker 2: Okay. Another essential biological aspect of the beaver before getting
Speaker 2: into their behavior is that they have a cloaca. So
Speaker 2: most mammals do not have a cloeca. There are some exceptions,
Speaker 2: you know. You look at the monotremes, golden moles, marsupial moles,
Speaker 2: ten rex just a few examples, but mammals have mostly
Speaker 2: lost these general purpose openings over the course of their evolution,
Speaker 2: but in beaver's they seem to be present as a
Speaker 2: case of secondary evolution, perhaps as an adaptation I've read against.
Speaker 2: It may have to do with the watery environments they
Speaker 2: find themselves in, protecting themselves against infections that might occur
Speaker 2: due to the state of that water. But it's also
Speaker 2: something and this will become important, I believe in the
Speaker 2: next episode as well. It can make it difficult to
Speaker 2: sex a beaver, as males and females look pretty much
Speaker 2: the same unless the female happens to be pregnant or
Speaker 2: nursing at the time. That you're trying to sex them.
Speaker 2: And when I say you, I of course mean people
Speaker 2: who have authority and expertise to be out in the
Speaker 2: wild trying to sex the beaver. You know, leave it
Speaker 2: to the professional biologists.
Speaker 3: Leave it to beaver scientists.
Speaker 2: Yes, so these various features aid the beaver in its
Speaker 2: primary enterprise of ecosystem engineering. We all know that beavers
Speaker 2: build dams. You know, this is of course is true
Speaker 2: of the cartoons. But what does that really mean? Why
Speaker 2: why are beavers building dams? What are they accomplishing? So
Speaker 2: they actively alter their ecosystem via the blockage of rivers
Speaker 2: and streams with structures of like, you know, sticks, mud,
Speaker 2: chunks of trees, that sort of thing, all cobbled together
Speaker 2: to dam up the water, and this allows them to
Speaker 2: create new lakes, new ponds, whole floodplains. Meanwhile, the lodges
Speaker 2: they construct for themselves are also made out of this
Speaker 2: kind of stuff, branches and mud and so forth, and
Speaker 2: they can only be accessed from underwater entrances in their
Speaker 2: constructed ponds.
Speaker 3: Yeah, so this is something I don't know if I
Speaker 3: realized before. I think a lot of people assume that
Speaker 3: beavers live in their dams. But I think the better
Speaker 3: way to think about it is beavers construct dams in
Speaker 3: order to block waterways, which causes the area upstream of
Speaker 3: the dams to deepen and have a more lake like
Speaker 3: environment rather than a flowing river or stream. And then
Speaker 3: in that flooded area that is where they build the
Speaker 3: lodge they live in. So they sort of create a
Speaker 3: flooded area, which can it conserve multiple purposes, one to
Speaker 3: house the lodge, but then also they can sort of
Speaker 3: dig out from there. I think you're about to mention
Speaker 3: something about this.
Speaker 2: Yeah, they're a lot like humans. Human beings do this
Speaker 2: with their modern technology. They come to say a dry
Speaker 2: desert environment or a swamp environment, and they're like, you
Speaker 2: know what would go great here? What I would like
Speaker 2: for my purposes of living here. I'd love it to
Speaker 2: be just like a nice little park with some nice
Speaker 2: you know, and maybe a few trees. I'm going to
Speaker 2: change everything so that it fits my needs. So the
Speaker 2: primary purpose for the beaver dam is to create a
Speaker 2: protective body of water for that lodge, making it even
Speaker 2: more difficult for predators to get at them. And even
Speaker 2: if predators were to get to them, they have that
Speaker 2: underwater escape route in the event of an attack, that's
Speaker 2: the only the only way in and out. Now. It's
Speaker 2: worth noting, however, that especially in parts of Eurasia, beavers
Speaker 2: don't always have the same predator threat they once did,
Speaker 2: but they build anyway because no one told them not to.
Speaker 2: And also, more seriously, like, even though they are not
Speaker 2: predators now, I mean that's you know, any kind of
Speaker 2: evolutionary change would occur over a much vaster period of
Speaker 2: time than the removal of their predators amounts to.
Speaker 3: Right, So an environment full of say like gray wolves
Speaker 3: and bears may have shaped them. And even if there
Speaker 3: are many fewer of these predators than there once was,
Speaker 3: that they are still the animal made by that world.
Speaker 4: Right.
Speaker 2: For instance, they're still certainly nocturnal creatures. I mean they're
Speaker 2: also active, you know, dusk and dawn a little bit,
Speaker 2: but during the day proper they're inside, they're resting, and
Speaker 2: part of that is to avoid predators. Now, you mentioned earlier,
Speaker 2: Joe that even just looking at videos you can tell
Speaker 2: that they're more awkward on land than they are in
Speaker 2: the water. And that's of course another big important aspect
Speaker 2: of their damming of waterways, creating this sort of vast
Speaker 2: flood plain, like turning a stream going through a forest
Speaker 2: or something to this effect into kind of a flooded
Speaker 2: forest environment. This opens up speedy water routes back to
Speaker 2: their lodge. From perspective, feeding grounds.
Speaker 3: Yes, sort of the same way. You could imagine it,
Speaker 3: like humans creating roads like paved roads between say the
Speaker 3: farms that they work during the day and the houses
Speaker 3: they live in. But beavers would do this by instead
Speaker 3: creating flooded areas. Especially, they can sort of like dig
Speaker 3: out channels along the bottom that the water from these
Speaker 3: flooded areas can run into, allowing them to have a
Speaker 3: sort of canals like roads made of water where they
Speaker 3: can move quickly, where they can move submerged, which is
Speaker 3: safer and better for them than trying to move awkwardly
Speaker 3: over land.
Speaker 2: Yeah. Now, in doing this, of course, they alter the
Speaker 2: ecosystem local ecosystem in a major way, opens up opportunities
Speaker 2: for various other organisms as well, and also discuss some
Speaker 2: of the potential downsides at least for some organisms in
Speaker 2: a bit. But at any rate, this cements the beaver's
Speaker 2: place as a keystone species. Beaver's just just completely change
Speaker 2: the immediate environment, produces more open water, higher water tables.
Speaker 2: And yeah, it's this entire system they have going for
Speaker 2: them here is just so fascinating. You can if you
Speaker 2: look online, you can find some some side profiles, some
Speaker 2: cutaways of what the lodge looks like, and it's pretty ingenious.
Speaker 2: It also serves as a place for them to store
Speaker 2: food and even provides recue huge during frozen months. They
Speaker 2: don't hibernate properly, but they can hold up in there.
Speaker 3: One of the things I've read about is that they
Speaker 3: often can store lots of food, so they are vegetarians
Speaker 3: that eat actually, like you know, parts of trees, vegetation
Speaker 3: from all around them, which they can keep stored in
Speaker 3: the water underneath the pond created by their dams. And
Speaker 3: that's an interesting thing. They can raise the water level
Speaker 3: in order to help protect areas of food storage in
Speaker 3: the water for the winter, because by raising the water
Speaker 3: level they create more area underneath that won't freeze over
Speaker 3: when the weather gets cold.
Speaker 2: Yeah, and these these lodges and dams that they can
Speaker 2: they even though the beavers themselves tend only live about
Speaker 2: I think eight years max. A single lodge and dam
Speaker 2: can be maintained over generations, so the lodges may end
Speaker 2: up with like several stories to them, and the dams
Speaker 2: can get quite massive. There's an Alberta area dam that
Speaker 2: was built apparently in the nineteen seventies, initially wasn't discovered
Speaker 2: till around two thousand and seven because it's just out
Speaker 2: in the middle of nowhere. It's not like in downtown Alberta.
Speaker 2: It's like out in the boonies. And it's thought to
Speaker 2: be the world's largest beaver dam known beaver dam anyway,
Speaker 2: covering a good half mile. There's actually an Alice Obscure
Speaker 2: article about it. If anyone's interested, just look up world's
Speaker 2: largest beaver dam and you can see some like aerial photographs.
Speaker 3: You know, something interesting I was reading about was the
Speaker 3: role of beavers in maintaining ecosystem health by allowing for
Speaker 3: a greater diversity of different types of plant life to thrive.
Speaker 3: I think sort of in the same way that forest
Speaker 3: fires you might think of them as purely destructive. Of
Speaker 3: course they are destructive, but you know, forest fires occur
Speaker 3: naturally all the time, and when a forest burns, that
Speaker 3: creates sort of new opportunities for new types of plants
Speaker 3: and other life forms to thrive in a place that
Speaker 3: was once covered up by you know, a lot of
Speaker 3: tree camp. So in the areas around beaver dams and lodges,
Speaker 3: they will clear out lots of the trees. They literally
Speaker 3: chew them down and they'll fall, and you know, the
Speaker 3: beavers will do what they will with them. But this
Speaker 3: creates all kinds of opportunities for other plants and other
Speaker 3: life forms that wouldn't normally thrive in the forest to
Speaker 3: have a shot.
Speaker 2: Yeah. Yeah, the paper that I came across was talking
Speaker 2: about sort of like the pros and cons. I have
Speaker 2: another one I'll get into about some of the potential benefits,
Speaker 2: but just to give you a full idea of sort
Speaker 2: of the rodent altered landscape we're talking about here, I
Speaker 2: was looking at a twenty fifteen paper published in IOP
Speaker 2: conference series or presented in the IOP conference series Earth
Speaker 2: and Environmental Science. This one is this was by Raskova
Speaker 2: to Mina at All, and they talk about some of
Speaker 2: the positive and negative consequences, at least initially stressing some
Speaker 2: of the negatives maybe that are not at least instantly
Speaker 2: discussed as much. But you get soil overwetting obviously, because
Speaker 2: you're getting flooding occurrently that occurs, you also can have
Speaker 2: water stagnation that results in lack of oxygen, high carbon concentration,
Speaker 2: and the death of many aquatic organisms. And then the
Speaker 2: flooding can also cause vegetation death. But at the same time,
Speaker 2: the authors are stressed that it can result in a
Speaker 2: rise in the biodiversity of water organisms. So you know,
Speaker 2: they're changing everything. They're changing the balance of the local ecosystem,
Speaker 2: and it's creating a lot of opportunities for new things,
Speaker 2: but it is also cutting things short for things that
Speaker 2: we're living there already. Now, a really interesting study that
Speaker 2: I came across this was a twenty twenty two Stanford
Speaker 2: study by Dewey at All published in Nature Communications, And
Speaker 2: in this paper they point out that beaver habitat ranges
Speaker 2: in the US are going to continue to widen with
Speaker 2: warming temperatures driven by climate change, but the benefits of
Speaker 2: their dam building will actually quote overshadow climate extremes quote.
Speaker 2: So this is not to say beaver dams will cancel
Speaker 2: out climate change or anything like that, but in some
Speaker 2: respects it kind of lessens the blow specifically as far
Speaker 2: as water quality in mountain watersheds are concerned. Beaver dams
Speaker 2: can raise water levels upstream and divert water into soil
Speaker 2: and surrounding waterways, and this ends up sort of, This
Speaker 2: ends up like creating a robust filter system, a filtration
Speaker 2: system for excess nutrients and contaminants for the water before
Speaker 2: it passes on downstream. So today beaver's in North American
Speaker 2: Eurasia are both doing great. They have bounced back from
Speaker 2: near extinction due to hunting, and we may touch on
Speaker 2: some of that a little bit more in the next episode,
Speaker 2: but because there are a few different reasons that have
Speaker 2: driven beaver hunting over the years. But to go back
Speaker 2: to speaking of their construction of dams and their changing
Speaker 2: of the environment, there's another great illustration I came across
Speaker 2: by Nicholas Defer, who lives sixteen forty six through seventeen twenty,
Speaker 2: and this is just a small scene from a larger map.
Speaker 2: He was a French cartographer, so this illustration is just
Speaker 2: filling in some of the blank spaces, like we've discussed
Speaker 2: before on some of these older maps. But this illustration
Speaker 2: shows beavers at work. They are downing trees and they
Speaker 2: are dragging off the wood to build things. The beavers
Speaker 2: themselves look largely accurate. There may be a little more
Speaker 2: bear like, but the basic morphology is there. The main
Speaker 2: problems here are that, first of all, there's like, you know,
Speaker 2: one hundred beavers in this one image, like they're working
Speaker 2: as an army. And then also like clearly there wasn't
Speaker 2: a lot of detail on how they carry the wood,
Speaker 2: because the central beav that you see is standing up
Speaker 2: in a bipedal posture with an armload of wood thrown
Speaker 2: over his shoulder like a human being.
Speaker 3: Yeah yeah, like a Paul Bunyon carrying an axe.
Speaker 4: Yeah.
Speaker 2: But I like the spirit of industry that they captured here,
Speaker 2: despite some of the ridiculous details, and again a huge
Speaker 2: improvement over some illustrations from previous centuries.
Speaker 3: I wonder is this one of the maps we looked
Speaker 3: at in our Horror Vakae episodes where we were talking
Speaker 3: about maps with excessive illustrations.
Speaker 2: I don't believe it is. I looked at a bigger
Speaker 2: version of the map and I almost included it in
Speaker 2: our notes, and I don't think I had seen it before.
Speaker 2: It was a map that it's known as the Beaver map.
Speaker 2: And has to do with the locations of beavers, because
Speaker 2: it has to do with the hunting of beavers, which
Speaker 2: again was quite a big industry for a while there,
Speaker 2: so big that it just about wiped them out. So
Speaker 2: the large semi aquatic rodents have come to flood the
Speaker 2: world and to remake it according to their designs. But
Speaker 2: the weirdness and the complexity doesn't stop there. Joe tell
Speaker 2: us a little bit about beaver society and about beaver
Speaker 2: tool use.
Speaker 3: Yeah, Rob, I think you found one of these papers first,
Speaker 3: and that's what started this whole thing. But I got
Speaker 3: lost on a going down a rabbit hole or maybe
Speaker 3: a beaver canal, trying to search out examples of possible
Speaker 3: tool use documented in beavers, and in fact, there are
Speaker 3: a few very interesting different observations corresponding to each of
Speaker 3: the extant species. Beavers clearly are an interesting type of
Speaker 3: animal to look at for signs of tool using intelligence,
Speaker 3: since they are masters of manipulating their environment through the
Speaker 3: dams and the lodges they build. Though I think it's
Speaker 3: interesting that nest building is often not typically thought of
Speaker 3: or not sort of front of mind as an example
Speaker 3: of tool use, and there are different examples the different
Speaker 3: zoologists or animal behavior experts will use to try to
Speaker 3: define tool use. So in the papers I was looking at,
Speaker 3: a few different standards were cited. One is a definition
Speaker 3: of tool use by a researcher named Alcock, who says
Speaker 3: it is quote the manipulation of an inanimate object that
Speaker 3: improves the organism's efficiency in altering the position or form
Speaker 3: of some other object. So, you know, using an inanimate
Speaker 3: object from the environment to better alter the former position
Speaker 3: of something else. Another definition I've found cited this is
Speaker 3: from Beck in nineteen eighty quote the external employment of
Speaker 3: an unattached environmental object to alter more efficiently the form, position,
Speaker 3: or condition of another object, another organism, or the user
Speaker 3: itself when the user holds or carries the tool during
Speaker 3: or just prior to use, and is responsible for the
Speaker 3: proper and effective orientation of the tool. Now, I appreciate
Speaker 3: all of the conditions on that, because I think it
Speaker 3: is important for people to be specific about what they're
Speaker 3: talking about when they look for examples of tool use.
Speaker 3: But I also wonder, once you're specifying that many conditions,
Speaker 3: is the category of tool use becoming more like a
Speaker 3: function of the definition you lay out than a fundamentally
Speaker 3: different type of activity itself than some other activity that
Speaker 3: wouldn't quite fit this definition.
Speaker 2: Yeah, I mean, and sometimes we can almost get too
Speaker 2: hung up, I think, on the on the idea of
Speaker 2: tool use and the definition of tool use, because we'll
Speaker 2: look at the most complicated burden, nest or bower that
Speaker 2: you can imagine and will be like, well, it's intricate,
Speaker 2: it's amazing, it's beautiful. But have you seen this monkey
Speaker 2: stabbing a smaller monkey with a stick? You know, it's
Speaker 2: you know, it can almost you can almost set it
Speaker 2: up as this this thing that is the thing that
Speaker 2: we do. You know, that is a very there's something
Speaker 2: very human about tool use, and you know, obviously a huge,
Speaker 2: huge aspect of human life and human development. But yeah,
Speaker 2: it seems like at times a lot of extra mental
Speaker 2: gymnastics has to be utilized in order to even discuss it.
Speaker 3: So I'm not going to get super hung up on
Speaker 3: definitions of tool use or what really counts as tool
Speaker 3: use today. We've talked about some of those debates in
Speaker 3: plenty of episodes in the past. Instead, I'm just going
Speaker 3: to like talk about some studies describing specific behaviors and
Speaker 3: you can make up your own mind about whether it
Speaker 3: seems like tool use to you. So the first thing
Speaker 3: I want to talk about is an older observation. It's
Speaker 3: older than either of the two papers that I'm going
Speaker 3: to discuss here, but it's cited in the first of them,
Speaker 3: and I'll get to that paper itself in the second.
Speaker 3: But the observation is that a researcher named Georgio Pilleri
Speaker 3: observes something interesting while studying two captive beavers at the
Speaker 3: Burn Brain Anatomy Institute in nineteen eighty. So, the beavers
Speaker 3: were living in a concrete pool that was supplied with
Speaker 3: a constant flow of fresh water, and overflow of this
Speaker 3: pool was routed away through a series of three drain holes,
Speaker 3: each zero point eight centimeters in diameters little holes, And
Speaker 3: the beavers had been given a supply of sticks and
Speaker 3: twigs to do what they wanted with, and for some reason,
Speaker 3: what they did is they selected and cut three sticks
Speaker 3: from their supply to the exact dimensions needed to plug
Speaker 3: the tiny drain holes that where water drained away from
Speaker 3: their pool, and this completely stopped the flow of water
Speaker 3: away from the pool. Now, what's going on here? At first,
Speaker 3: It was kind of hard for me to believe this
Speaker 3: would be fully intentional behavior, as in, like the beavers
Speaker 3: understood that they were plugging the drains to stop the
Speaker 3: flow of water from their enclosure. But then I thought,
Speaker 3: you know, I guess I wouldn't be surprised if beaver
Speaker 3: have like a sense for detecting gaps in dams and
Speaker 3: plugging them, Like maybe they're good at sensing. My first
Speaker 3: instinct was maybe they sense like the delta pee, you know,
Speaker 3: the difference in pressure, like when water from a large
Speaker 3: pool is flowing out of a small pipe or hole,
Speaker 3: and you could feel that pressure that would like get
Speaker 3: your hands stuck to the hole if you held it there,
Speaker 3: or which in larger scenarios can be of a great
Speaker 3: danger to divers. You know, you don't want to go
Speaker 3: near like the intake hole and a dam if you're
Speaker 3: diving near it. I thought, maybe they sensed the delta pee,
Speaker 3: and so they sense that and they naturally want to
Speaker 3: plug it up. But I didn't know. However, I then
Speaker 3: sort of came across an answer. So I was watching
Speaker 3: a segment on North American beavers from BBC Earth, narrated
Speaker 3: by David Attenborough, and this documentary segment captured a scene
Speaker 3: of beavers finding a leak in their dam and then
Speaker 3: getting right to work retrieving wood, vegetation and clumps of
Speaker 3: ediment down from the bottom of the pond to plug
Speaker 3: up the leak in the dam where water was running
Speaker 3: over the top, and Attenborough in this documentary segment narrates
Speaker 3: that beavers are thought to detect these leaks by hearing
Speaker 3: the sound of trickling water, and when they do, they
Speaker 3: begin repair work almost immediately. So it seems to be fastidious,
Speaker 3: almost compulsive, this compulsive desire to fix the holes when
Speaker 3: they hear the water trickling, and this would make the
Speaker 3: drain plugging behavior in the concrete enclosure in the eighties
Speaker 3: make a lot more sense. So I decided to look
Speaker 3: into this further to see if this was indeed true
Speaker 3: to some degree. It seems it is, and so I
Speaker 3: didn't have time. This was soon before we started recording.
Speaker 3: I didn't have time to find the primary reference on this,
Speaker 3: but I did find a good twenty fifteen Gizmoto blog
Speaker 3: post by Esther inglis Arkele writing up summarizing the research
Speaker 3: of a Swedish zoologist named Lars Wilson, who studied beavers
Speaker 3: back in the nineteen sixties, and according to the summary,
Speaker 3: Lars Wilson found that dam building was instinctual rather than learned,
Speaker 3: and the way Wilson identified with this was that if
Speaker 3: you took young beavers and you separated them from their
Speaker 3: parents at birth, they would still build dams basically the
Speaker 3: same way, using the same techniques as their parents, even
Speaker 3: though they were clearly not having the opportunity to be
Speaker 3: taught to do that. So it seems based on that
Speaker 3: at least this is probably a routine behavior. It's based
Speaker 3: on beaver DNA. They don't have to be taught. But
Speaker 3: Wilson also found that beavers didn't always build dams. In
Speaker 3: environments with still water or only very gently moving water,
Speaker 3: dam building was not a priority. The beavers would just
Speaker 3: maybe they like dig a hole in the mud and
Speaker 3: just chill there, you know, they just wouldn't build. And
Speaker 3: so by manipulating different variables, Wilson identified the sound of
Speaker 3: trickling water as the primary trigger for dam building, even
Speaker 3: to the point of a discovery that I this was
Speaker 3: the part I found most fascinating. If you put a
Speaker 3: speaker in the beaver's enclosure and you played the sound
Speaker 3: of trickling water through it, the beavers would go to
Speaker 3: the speaker and start building on top of it. They
Speaker 3: would start piling up sticks and mud and branches over
Speaker 3: the speaker playing the water sounds. They were trying to
Speaker 3: plug the speaker to make it stop leaking.
Speaker 2: Oh my goodness.
Speaker 3: Wilson also found that if outflow pipes, so you had
Speaker 3: a place where there was actually water leading away from
Speaker 3: the from the pool, but you carefully designed the pipe
Speaker 3: so that they made no noise, the beavers would not
Speaker 3: be able to find and cover them. So this might
Speaker 3: lead you to think, okay, so like the louder the
Speaker 3: rushing of the water, the more beavers want to make
Speaker 3: a damn there. But it also seems like it's not
Speaker 3: quite that simple, because I was reading a news article
Speaker 3: from the Harvard Graduate School of the Arts and Sciences
Speaker 3: called Damned if They Do by Paul Massari. This article
Speaker 3: profiles the research of an environmental engineer named Jordan Kennedy
Speaker 3: who has done research on beavers and their dam building
Speaker 3: practices and the environmental effects thereof. And Kennedy says that
Speaker 3: it can't just be about like the magnitude of sound
Speaker 3: of moving water, or beavers would be trying to build
Speaker 3: dams across Niagara Falls, you know, just like loud, violent,
Speaker 3: rushing waters where building would be totally impractical. So instead,
Speaker 3: there's got to be a kind of Goldilocks zone for
Speaker 3: damn construction, something that the beavers naturally detect that allows
Speaker 3: them to know, Okay, this is about the right amount
Speaker 3: of flow to try to dam up.
Speaker 2: Yeah, yeah, damming up Niagara Falls. Like obviously that would
Speaker 2: be great, Like that's kind of like the beaver fan fiction,
Speaker 2: that's the pipe drain, But is it practical. No, you
Speaker 2: need to have that just the right environment that can
Speaker 2: then be manipulated to make the ideal environment for the beaver.
Speaker 3: Right, So the author of this article right now, it's quote,
Speaker 3: the water in a beaver's habitat needs to be a
Speaker 3: certain depth, for instance, to keep a food cash from
Speaker 3: freezing to the bottom in winter and to enable them
Speaker 3: to evade predators. The plants that beavers prefer to eat
Speaker 3: flourish best when water flows at a certain velocity. So
Speaker 3: you're looking for this Goldilocks zone, an area of a
Speaker 3: certain amount of water flow, maybe a certain narrowness of
Speaker 3: the channel or certain depth of the channel and that's
Speaker 3: the place where you want to dam it up. And
Speaker 3: beavers apparently they locate that A big part of the
Speaker 3: sense data informing them of that area appears to be sound.
Speaker 3: Maybe the overwhelming part of it is sound, but there
Speaker 3: may be other cues as well, And so I don't know.
Speaker 3: I thought this was so interesting, And I'm just trying
Speaker 3: to imagine what it's like to be a beaver to
Speaker 3: have this powerful instinctual drive to plug leaks. So imagine
Speaker 3: the same kind of base level instinctual drive that humans
Speaker 3: might have for sex, or for food, or to care
Speaker 3: for children, all the like the most powerful drives in
Speaker 3: our brains. But there's a drive like that to hunt
Speaker 3: down the source of anything that sounds like trickling water
Speaker 3: and to just plug it with junk. You know, I
Speaker 3: don't know, that's like that's another that's another type of
Speaker 3: mind experience or relationship to the environment.
Speaker 2: Wow wow, yeah, Like what would yeah, how would like
Speaker 2: we can't help but extravolate that into like a a
Speaker 2: human like intellect and human like culture, Like what would
Speaker 2: advance beaver civilization be? Like? Would they actually go after
Speaker 2: like complete inundation, like a complete flooding situation, the destruction
Speaker 2: of of of all naturally occurring waterfalls, or would they
Speaker 2: just kind of dream about it? Or what would their
Speaker 2: TV shows be? Would it just be like countless channels
Speaker 2: of leak plugging and so forth.
Speaker 3: The speaver thought she had it all, but then she
Speaker 3: heard the trickle and couldn't find it searching, Like all
Speaker 3: dramas begin with the conflict of hearing a trickle.
Speaker 2: That's the called adventure.
Speaker 3: Yeah, but anyway, all that stuff I just read about
Speaker 3: got kicked off because I was reading that anecdote about
Speaker 3: the findings of Giorgio Pillari in nineteen eighty three, which
Speaker 3: was cited in a paper by D. M. Barnes called
Speaker 3: Possible tool use by beaver's Castor canadensis in a Northern
Speaker 3: Ontario watershed published in The Canadian Field Naturalist in two
Speaker 3: thousand and five. So this is one of the main
Speaker 3: two papers I was looking at about possible cases of
Speaker 3: tool use in beaver's Barnes says that this report is
Speaker 3: based on evidence relating to the North American beaver that's
Speaker 3: Castor candidensis at a remote damn site in the Chapleaux
Speaker 3: Crown Game Preserve in northern Ontario. The author says, at
Speaker 3: this location they found a clump of willow stems, so
Speaker 3: like little small tree trunks that had been cut by beavers.
Speaker 3: But the fascinating thing was they were cut at the
Speaker 3: extraordinary height of approximately one meter off the ground. Beavers
Speaker 3: are not that tall Normally, these beavers cut at an
Speaker 3: average height of about thirty centimeters, so the beavers were
Speaker 3: chomping off these willow trees at three times the normal
Speaker 3: height they could reach with their teeth. Barnes writes, quote,
Speaker 3: I made a careful examination of the area and found
Speaker 3: that there was no apparent way the beavers could have
Speaker 3: cut the stems at such a height. When I studied
Speaker 3: the willow clump more closely, I noted that there was
Speaker 3: a freshly cut willow stem approximately twelve centimeters in diameter,
Speaker 3: leaning against the main stem of the willow clump. Its
Speaker 3: approximate angle was forty five degrees. In addition, I observed
Speaker 3: cutting at both ends of the leaning willow segment, and
Speaker 3: then there was a There was a photo accompanying this
Speaker 3: in the article. Now, at first the author thought that, okay,
Speaker 3: so this is a log propped up forty five degrees
Speaker 3: against the tree that is cut off very tall. The
Speaker 3: author thought, maybe this log there had simply fallen that way.
Speaker 3: I don't know, it's something that the beaver cut and
Speaker 3: then it fell. But that seemed impossible on further examination,
Speaker 3: because the log was clearly from a different tree than
Speaker 3: the stem it was leaning against, like there was different
Speaker 3: bark texture and color and so forth, and its position
Speaker 3: just did not seem plausible if it had fallen from above.
Speaker 3: Another possibility the author considered was that these willow trunks
Speaker 3: had been foraged while there was heavy snow on the
Speaker 3: ground in the winter. So maybe the beavers were able
Speaker 3: to reach a meter up the trunks of these trees
Speaker 3: by crawling around on top of the snow.
Speaker 2: Okay, but the.
Speaker 3: Author things that's really unlikely given the position of the
Speaker 3: willow clump relative to the beaver dam and lodge and
Speaker 3: its entrance and exit. It seems it would have required
Speaker 3: a major overland journey by the beavers on the top
Speaker 3: of the snow in the winter at a time where
Speaker 3: this just would not fit with their normal behavior. Instead,
Speaker 3: the author suggests that maybe what happened here is the
Speaker 3: beaver used a prop. The beaver used a piece of
Speaker 3: a log that it had cut off at both ends
Speaker 3: and propped it up against the base of the trees,
Speaker 3: and then climbed up that and was able to chew
Speaker 3: off the willow stems at an upper level rather than
Speaker 3: a lower level. Now, why would this even be beneficial?
Speaker 3: The author says this would be probably to reduce foraging time.
Speaker 3: So the longer you forage, number one, the more thermal
Speaker 3: stress you're exposed to not being the right temperature, but
Speaker 3: more importantly, the longer you are exposed to predation. Apparently
Speaker 3: beavers do not like to spend a lot of time
Speaker 3: out on the ground out of the water. They were
Speaker 3: trying to hustle as fast as they can whenever they're
Speaker 3: out there cutting, and in this case, apparently using a
Speaker 3: cut stem to climb up the willow trunks to access
Speaker 3: a higher up part of the tree to chew through
Speaker 3: would have meant that they had to spend less time
Speaker 3: chewing and less time cutting.
Speaker 2: All right, So they go like a little bit higher.
Speaker 2: They just it's going to be less it's going to
Speaker 2: be a narrower bit of wood to chew through.
Speaker 3: That's what I assumed. It didn't specify exactly why cutting
Speaker 3: higher up was reduced foraging time. But that was my interpretation.
Speaker 2: I could be wrong, and that's why they potentially could
Speaker 2: be using essentially a beaver ladder a beaver bit of scaffolding.
Speaker 3: Right, but we don't know. This is just one observation.
Speaker 3: And also they didn't see them doing it. They just
Speaker 3: found this strange piece of scaffolding there later.
Speaker 2: Yeah. More mysteries related to and I mean, I guess
Speaker 2: this is kind of cutting into some of the mysteries
Speaker 2: involved in these wildly inaccurate depictions of beavers, is that
Speaker 2: these are creatures that live of often in very rural situations,
Speaker 2: far from human activity. They're probably doing it at night,
Speaker 2: and they're spending as little time necessary doing it out
Speaker 2: where other eyes could see them.
Speaker 3: Right, Okay. Second paper I came across alleging possible tool
Speaker 3: use behaviors by beavers. This is called tool use in
Speaker 3: a display behavior by Eurasian beavers or castor fiber in
Speaker 3: the journal Animal Cognition by Thompson at All in two
Speaker 3: thousand and seven. So here the authors write that documentation
Speaker 3: of tool use is relatively rare in rodents, and prior
Speaker 3: to this paper there were no documented cases. They knew
Speaker 3: of of tools being used by rodents in what are
Speaker 3: called agonistic displays. Now, agonistic is a word used in
Speaker 3: the study of animal behavior to describe conflict or fighting.
Speaker 3: So an agonistic behavior is not necessarily fighting itself, but
Speaker 3: also could include social behaviors related to fighting. So these
Speaker 3: would include threat displays, trying to look big or otherwise
Speaker 3: intimidate another animal, displays of aggression, as well as things
Speaker 3: like submission or retreat behavior. The authors of this paper
Speaker 3: say that in their field observations of the Eurasian beaver,
Speaker 3: they witnessed a behavior that they call stick display, which
Speaker 3: they interpreted as an agonistic display behavior. And what this
Speaker 3: consisted of is beaver would go pick up an object,
Speaker 3: usually a stick, whenever a stick was available, and then
Speaker 3: it would rise up on its hind legs and then
Speaker 3: move the upper body rapidly up and down while holding
Speaker 3: the stick or other object in its mouth and front paws.
Speaker 3: And Rabi attached a picture for you to look at.
Speaker 3: They had a photo of this. In this photo of
Speaker 3: the beaver is in the shallow part of a waterway.
Speaker 3: It's standing up on its back legs. It's kind of
Speaker 3: I don't know how to it's kind of like roaring posture.
Speaker 3: But it's got a big old stick in its mouth,
Speaker 3: and it's gripping the dick with its two four paws,
Speaker 3: and the water is splashing all around. It's the stick,
Speaker 3: I guess, rapidly dips in and out.
Speaker 2: It's impressive, and it's it's frankly a little intimidating. This
Speaker 2: this beaver saying, behold, look at the at the feats
Speaker 2: of strength I am capable of.
Speaker 3: So several observations about this behavior. First of all, they say,
Speaker 3: beaver's only picked up these display sticks or other objects
Speaker 3: at the same location where they were used, and they
Speaker 3: were never seen modifying the objects, So it wouldn't It
Speaker 3: wasn't like they would carry a stick around and then
Speaker 3: and then use it in a different location or modify
Speaker 3: the stick in any way.
Speaker 2: So, for instance, compare it to like human tool use
Speaker 2: that we've discussed in the past. Rocks. This this would
Speaker 2: not be on the level of picking out favored rocks
Speaker 2: for throwing at other humans, polishing them, changing them, etc.
Speaker 2: This would be more on the level of when threatened,
Speaker 2: you might look down, grab a rock and use it.
Speaker 2: Though of course, in this case, the beavers are not
Speaker 2: hitting each other with the sticks. Allegedly, the hypothesis here
Speaker 2: is that they're using them as a pure defensive display.
Speaker 3: Right. Second thing. This often happened in shallow water, so
Speaker 3: the shaking of the stick would cause splashing in the
Speaker 3: surrounding water, but occasionally it also took place on dry land,
Speaker 3: such as in weeds, where there was no significant sound produced.
Speaker 3: So the authors think because it took place in both
Speaker 3: scenarios and when it was on dry land it didn't
Speaker 3: really make a noise, they think it is primarily a
Speaker 3: visual signal. An important bit of context is that Eurasian
Speaker 3: beavers are territorial. They live in family groups with usually
Speaker 3: a dominant breeding pair and then assorted offspring of that
Speaker 3: breeding pair, and they defend the borders of their territory
Speaker 3: from encroachment by other beavers. So they mark their territory
Speaker 3: by scent. This is done with secretions from the anal
Speaker 3: glands or castorium. Which castorium, I believe, we'll talk about
Speaker 3: more later in the series in part two allegedly smells
Speaker 3: like vanilla, but we'll come back. When rival beavers come
Speaker 3: into a family group's territory, the home turf beavers will
Speaker 3: react first of all with tail slapping. Rob you mentioned this.
Speaker 3: This is a loud signal that beavers make by repeatedly
Speaker 3: smacking the water surface with their tails. This is also
Speaker 3: used to alert members of the family group when a
Speaker 3: predator is cited. They also respond to unwelcome beaver presence
Speaker 3: by visual displays or sometimes with actual fighting, though physical
Speaker 3: fights are relatively rare. The observations carried out in this
Speaker 3: study were conducted on wild Eurasian beavers in southeast Telemark, Norway. Overall,
Speaker 3: the researchers observed one hundred and thirty one cases of
Speaker 3: stick display behavior that met the criteria for inclusion in
Speaker 3: their study, by four adult males, two adult females, and
Speaker 3: five unidentified animals. However, it seems that some individual beavers
Speaker 3: engaged in stick displays far more than the others.
Speaker 2: Quote.
Speaker 3: It was clear from our observations that one female beer
Speaker 3: and one male Froda where the main performers, with a
Speaker 3: contribution of fifty one point nine percent and thirty five
Speaker 3: point nine percent, respectively of the total number of stick
Speaker 3: displays observed. So what does that add up to. It's
Speaker 3: like eighty seven percent of stick displays were from.
Speaker 2: Two beavers Wow, go Froda.
Speaker 3: But the real champion is beer Get here. She's got
Speaker 3: more than half of them just under her belt.
Speaker 2: Yeah yeah, I mean really, beer Get needs to get
Speaker 2: get most of the credit here for Froda doing pretty
Speaker 2: well as well.
Speaker 3: So they say. Stick displays happened almost exclusively at the
Speaker 3: borders of beaver family group territory, and most displays appear
Speaker 3: to be directed at rivals. The displays were often preceded
Speaker 3: by scent marking, so this kind of suggests it probably
Speaker 3: is being used as an agonistic display. However, this behavior,
Speaker 3: while common in the groups observed in this study, is
Speaker 3: not necessarily generalizable to the total world population of these beavers.
Speaker 3: It has not really been observed in beavers generally across
Speaker 3: the full range, suggesting it may be specific to certain populations.
Speaker 2: Wow like even some like some sort of like localized
Speaker 2: beaver culture.
Speaker 3: Yeah, maybe apparently something. At the time of the study,
Speaker 3: the author said there were some isolated reports of similar
Speaker 3: behavior in a few North American beavers, but not most,
Speaker 3: and it was not found in all Eurasian beavers either.
Speaker 3: So the authors argue that stick displays might be especially
Speaker 3: favored in high pressure situations. From reading their description of
Speaker 3: the of the area. It seems like the groups observed
Speaker 3: in this study might be in especially crowded beaver territory,
Speaker 3: where like, you know, the areas around different family dams
Speaker 3: and lodge sites are sort of all butting up against
Speaker 3: one another. They also observed higher rates of stick displays
Speaker 3: in springtime, meaning it's possible it could have some association
Speaker 3: with breeding. But if the stick shaking is a genuine
Speaker 3: agonistic display behavior, the evolutionary purpose would probably be to
Speaker 3: convey honest information about the beaver's size and strength. So
Speaker 3: it's like, I'm big and strong. Look at how I
Speaker 3: can shake this stick. You don't want to bother actually
Speaker 3: getting into a fight with me, right, we don't have
Speaker 3: to do this.
Speaker 2: I like these sort of levels of communication that seem
Speaker 2: to exist between beaver groups here. You know, It's like,
Speaker 2: at the end of the day, all beavers really want
Speaker 2: to do is build things and plug holes. You know,
Speaker 2: they have they have a lot of hole plugging to do.
Speaker 2: They have they have a lot of work to accomplish.
Speaker 2: They don't really have time to get into these fights.
Speaker 2: These fights are just would be destructive. So instead, let's
Speaker 2: just make sure that we're very clear about how everyone
Speaker 2: feels about these these border scenarios, and if need be,
Speaker 2: let me just show you, give you a taste of
Speaker 2: what could happen. Just look at this stick lifting ability here.
Speaker 3: The neighbors are getting nosy, and Beer get shakes a
Speaker 3: branch and it's like, no, don't make me do it.
Speaker 3: Don't make me do it. And it seems most of
Speaker 3: the time they're like, Okay, I won't make you do it,
Speaker 3: Beer gat Man. I think we've got to be out
Speaker 3: of time for part one of Beaver's here, right, but
Speaker 3: there will be more.
Speaker 2: Yeah, in the next episode, we're gonna we're going to
Speaker 2: get back to that idea, that that false idea of
Speaker 2: beavers whilst being hunted deciding to chew their own testicles
Speaker 2: off again that you see various examples of, particularly from
Speaker 2: like illuminated manuscripts and so forth and bestiaries. We'll come
Speaker 2: back and to discuss that, plus who knows what else
Speaker 2: we'll uncover about beavers in our research. In the meantime,
Speaker 2: we'd love to hear from everyone out there if you
Speaker 2: have any especially since a lot of times we do
Speaker 2: these Tuesdays to Thursday. This one's going to be a
Speaker 2: Thursday to Tuesday, so who knows, you might be able
Speaker 2: to get some really core beaver facts and beaver experiences
Speaker 2: into us before we record the next episode. You know,
Speaker 2: something you've picked up somewhere or just you know, accounts
Speaker 2: of observing beavers in the wild. I'd love to hear
Speaker 2: about that. So, whatever your feedback, whatever your thoughts, share
Speaker 2: them with us. We would love to hear from you.
Speaker 2: Just a reminder that Stuff to Blow Your Mind is
Speaker 2: a science podcast with core episodes on Tuesdays and Thursdays,
Speaker 2: so look for those in the Stuff to Blow your
Speaker 2: Mind podcast feed wherever you get your podcasts. On Mondays
Speaker 2: we do a listener mail episode. On Wednesdays we do
Speaker 2: a short form artifact or monster fact episode. I know
Speaker 2: sometimes people say I wish they were longer, Well they're short.
Speaker 2: That's part of how it works. But occasionally we're going
Speaker 2: to put out We're going to continue to experiment, experiment
Speaker 2: with putting out omnibus episodes that may take up like
Speaker 2: multiple related monster facts or artifacts and put them out
Speaker 2: so periodically you'll get a longer one in there as well.
Speaker 2: So yeah, let us know if you're liking that, and
Speaker 2: we can keep doing it. Oh, and then on Fridays
Speaker 2: we set aside most serious concerns to just talk about
Speaker 2: a weird movie on Weird House Cinema.
Speaker 3: Huge thanks to our audio producer JJ Posway. If you
Speaker 3: would like to get in touch with us with feedback
Speaker 3: on this episode or any other, to suggest topic for
Speaker 3: the future, or just to say hello, you can email
Speaker 3: us at contact at stuff to Blow your Mind dot com.
Speaker 1: Stuff to Blow Your Mind is production of iHeartRadio. For
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Speaker 1: or wherever you listen to your favorite shows.