Extinction: The Call of the Giant Beaver

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Lucas: Welcome to Making a Monster: Extinction, investigating the stories of vanished species as we gather them into a bestiary for 5th edition Dungeons & Dragons called Book of Extinction, coming to Kickstarter in March of 2023 and previewing now on the Mage Hand Press Patreon. This is the sound of GenCon, where I spent this last weekend sharing the book with gamers and makers from all over the world. But tucked away not too far from the biggest 4 days in gaming is a surprising gem of natural history.

Welcome to Richmond, Indiana podcast listener. I’m here on the trail of an ice age giant. We’re at the Joseph Moore Museum at Earlham College.

Prehistoric megafauna are an integral part of the fantasy genre, giant monsters who awaken the kind of fear humans only feel in the presence of an apex predator more powerful than themselves. This week I want to introduce you to one of the most unexpectedly fascinating creatures among that pantheon of ice age beasts and her fascinating journey through near time alongside an Egyptian mummy, a mastodon, and maybe the most dedicated graduate students in history. Our guide on this journey [00:02:00] is Doctor Heather Lerner.

We’re resurrecting megafauna for D&D! Click to get ’em monsters!

Heather Lerner: So I’m Heather Lerner. I’m the director of the Joseph Moore Museum, which is a regional natural history museum at Earlham College; also an associate professor of biology and museum studies. I was recruited from the Smithsonian where I was working in ancient DNA. And I came out here for an interview and got to go into the museum and see the world’s most complete fossil giant beaver. And I will confess at that moment, I was, let’s see, eight months pregnant with twins. And I thought the giant beaver was pretty cool, but I mostly identified with the giant ground sloth , which, um, was not exactly the reaction they were looking for.

Lucas: Heather gave me an inside tour of the Joseph Moore Museum, including a lot of stuff the general public doesn’t get to see. And in the interest of better understanding the ancient megafauna in Book of Extinction, Heather will introduce us to the giant beaver in the order in which a scientist of her caliber would – starting with today and working backward.

Casteroides ohioensis, the Giant Beaver, at the Joseph Moore Museum at Earlham College in Richmond, Indiana

Heather Lerner: The giant beaver is just an incredible creature. And from the first moment that I knew about it in my interview here, I thought, “I know how to get DNA out of really old things. And I would love the challenge of trying to sequence DNA from the extinct giant beaver and see what we could learn from that.”

So I started there and then started thinking, well, what, why would that be useful? Just cuz you can do something doesn’t mean you should do something, which I have to tell my children. just cuz you can doesn’t mean you should. Um, so I spent a while really learning about beavers.

so we know there are two species today of modern beavers. There’s the North American and the Eurasian, they’re closely related to each other and to nothing else , which makes it very hard to figure out things about their past. [00:04:00] Why do they look the way they do? Why do they do the things they do? If we don’t have that evolutionary record, it just really hinders the explanations that we can come up with.

So, um, one of the things you can do to try to figure out close relatives is to add in extinct species. And it turns out that what beavers are closely related to are a lot of other extinct species , um, which includes the giant beaver. And the giant beaver is pretty cool because it’s part of the group of beavers that you would be more familiar with in terms of living an aquatic lifestyle. That’s what you think of when you think of beavers, right? Ponds, streams, that kind of thing. Yeah. Um, it turns out this is super cool. There’s a whole group of extinct beavers that are called fossorial or upland digging beavers. Right. Who knew? It turns out people who study fossils know. So, um, there are maybe seven to twelve genera of extinct fossorial, terrestrial, upland, burrowing, beavers.

And they go back far enough in time that we are not probably gonna get DNA out of them. so figuring out those relationships is probably in terms of using DNA, a loss cause, but Casteroides ohioensis the giant beaver. Was around until not that long ago. So maybe 10,000 years ago. And that is a tractable question using ancient DNA techniques.

That’s a timeline in which things are preserved well enough that you can get DNA. So we set about trying to sequence the giant beaver to help us figure out those relationships in particular, when did beavers become aquatic? Since we know there’s [00:06:00] this whole Upland group, when did this thing that we associate with beavers become true.

So you can use lots of clues, like, um, their body shape from the extinct species and sort of piece things together there. But unless, you know, when those species really lived, it can be hard to get that timeline of evolution. So using DNA, we can really anchor that those trait evolutions in time. So that’s what we did. We sequenced the mitochondrial genome, um, of the extinct beaver and, um, we’re able to figure this out.

Lucas: I just want, I just wanna pause on how cool that sentence is. That’s an incredible amount of work.

Heather Lerner: It was years in the making. Yeah, so first we spent a year building an ancient DNA lab here, which meant all the physical labor of cleaning out an entire room and taking every, everything out of there all like demolition work, plus painting everything and, uh, trying to get it to be a safe place to look at ancient DNA.

Because it turns out that we are shedding DNA all the time. as we walk around, we are just discarding our DNA everywhere. So if you wanna work on old things that don’t have a lot of their own DNA, you don’t wanna be adding your DNA to the mix. I did not wanna sequence myself. We wanted to sequence giant beaver.

So we needed that ancient DNA room. So we spent a year doing that, got that done. And then we were gonna start the process of taking the fossils, using a drummer and drilling out the hardest pieces of the fossils, which would be the pieces that had the most resistance to degradation. So they might have the best DNA in there.

Most intact. We wanted to start that process and there was a two week power outage. We only had three weeks set to be together to work on the project for that summer. And that was two thirds of our. Wow. So we didn’t do it [00:08:00] that year we ended up working on raptors instead, which was a great fun project. Um, but it did delay us a couple of years to be able to, to be able to do that process but it gave us time to learn more about beavers because it turns out there’s lots to know which I’m very excited that you want to know all about beavers you do, right?

Lucas: I do. Yeah.

Heather Lerner: Okay, good.

Lucas: That’s what I’m here for.

Heather Lerner: That’s great. we’re gonna have a great time. So I’m gonna take you into the collections. We’ll start with the modern beaver just to kind of orient you and then we’ll take some of those things with us and go find the fossils.

Lucas: Perfect.

Heather Lerner: Okay. Let’s do it.

Lucas: Great!

The Modern Beaver’s pelt

Heather Lerner: So the room we’re in is the mammal division. Um, and we have, oh, maybe five or 6,000 mammal specimens in here. Right. It doesn’t, you just look like that. Right. . Yeah. And that’s because the way that we prepare them is to, um, we remove all the insides and then we keep the skins preserved and then we put the fossil or the skeletons in a box.

So it’s all very tight and compact. Yeah. You, when you’re thinking of museums are thinking of taxidermy, which is posed animals, so that they look lifelike and that’s an art form, and that is amazing and important, but I can’t fit a lot of those posed puffed up animals in this room, this size, right? So we, we have study skins and there are, you know, depending on the size of the animal, there can be a hundred of ’em on a single tray.

So we are gonna go look for Castor canadensis which is the modern beaver, right. So that you can see it and touch it. Yes.

Lucas: Okay. I get to touch stuff.

Okay. Whoa.

Heather Lerner: We’re gonna take this out and put it over here.

Okay. So this [00:10:00] is a tray that has a modern beaver pelt on it. So it’s just kind of folded up like a little blanket. Um, and you can see the tail here on top can see that leather really tail . Yes, we are excited about the giant beaver, but it turns out modern beavers are fairly big themselves. Big . So what I want you to notice, because you did wash your hands, so I’m gonna allow you to touch it.

Lucas: Thank you.

Heather Lerner: You can feel that fur, what do you think of the fur?

Lucas: Oh man. Nowhere in my life, have I ever laid a hand on mink, but I know that aquatic animals have a hugely different fur to, uh, to terrestrial animals.

Exactly. Um, so we’ve got two different lengths and textures here. Already, um, kind a

Heather Lerner: Got that guard fur on the outside, .

Lucas: And then a softer, it’s so plush underneath , I’m getting chills cuz that’s the kind of weirdo that I am like.

Heather Lerner: And I think you can really identify with the people who were trapping and selling beaver pelts. This is incredibly warm, resilient, fur. This is gonna get you through a winter and winters were harsh, and we didn’t have access to all sorts of materials to keep warm and protected from the elements. It was a major concern. And so just feeling this, I think you can understand why they were so desirable, but also just with them being so desirable, why beavers faced such threats.

Um, so I wanted you to feel that. The other thing I wanted to show you is something that I learned when we spent all this extra time learning about beavers before sequencing. They do have this amazing thing and it’s on their hind feet.

Um, and it’s this adaptation to two of their toes. Um, and so this first toe here, so [00:12:00] there’s this fleshy pad and then there’s this, this nail. And what happens is when they, when they bend their, their paw like this, they trap their fur in between there. And it’s a comb and they do that with this one as well.

And it’s not as easily. No, here it is. Is that it? Here it is. Okay. It’s this one that has the big fleshy pad and the claw. And so it can squeeze that.

Lucas: So it’s that the claw is the same, uh, or rather the opposite, um, concave shape to the pads. Convex.

Heather Lerner: Yeah. So they nest within each other. If you like, take your pointer finger from each hand and sort of make a little arc and attach them to each other and you can squeeze between that.

Right. Right. And as they bend their, um, they flex that squeezes, the pad against the, against the nail your pad is attached to your nail. You’re not gonna run something between your pad and your nail on your finger. Huh. Right. Like you’re not gonna, I mean, you might run your fingers through your hair but imagine if you could flex down and actually turn that into a tight comb, that’s what they’re doing.

Amazing. And they do that with both of those toes. So that one that has the fleshy pad and the nail, and then this one that has like a split nail. So there’s a hard piece here and a hard piece there. And, and, you know, That’s gonna do different things. It’s like two different types of comb that they have so they can spread oil and they can remove debris and clean themselves, essentially with this little tool that’s on their hind feet.

Lucas: In terms of, I guess, yardage, if we’re thinking about textiles. Hmm. Um, how much would you get from one?

Heather Lerner: That’s a good question. A little more than a yard and it’s doubled over. So I’d say about a yard of fabric. Yeah. Amazing from just that one individual. And this does look like an adult. It is, it was a good size and it [00:14:00] was a male.

its weight was 57 pounds, 12 ounces. Its total length was 46 and a half inches. So that’s pretty long. Wow. Yeah. So we record information about the animals when we collect them as much as we possibly can, because like I said, you can’t go back and get that later. So any information we have about the habitat, it was in the things, it was doing photographs, video recordings, um, measurements, anything we can get, we will keep with the animals so that we have the most information.

Lucas: So then there’s a digital record that’s attached to this particular specimen. Incredible.

Heather Lerner: And like I said, we, in addition to having the skin that you’ve just been looking at or the pelt, um, we also try to keep, um, the skeleton and so this box has the skull for this one in it. Oh

Lucas: wow. I wasn’t ready for this.

Heather Lerner: So you can. Re-articulate the jaws there. And then you can see the, see that skull.

Lucas: Amazing.

Heather Lerner: So that’s a chomping.

Yeah. And you can see the teeth here, have this orange across them in the front , um, that’s probably related to some iron deposit there and that’s common in rodents, um, to have that. And that gives it real firm firmness to the teeth that even our teeth don’t have. We have enamel, but we don’t have that particular hard structure.

Um, and that is so it’s taking

Lucas: iron from its environment and it’s,

Heather Lerner: it’s sequestering it there yeah, we, we keep the iron in our blood and they probably have iron in their blood too, of course, being mammals. But, um, they must be depositing some of their teeth too.

Lucas: That’s incredible. They have metal teeth, you’re telling me?

Heather Lerner: Yeah, basically. Yeah. That’s a good way of thinking of it. Yes, that is correct. yeah. And that really, um, [00:16:00] provides that strength that they need for all of the chewing that they would do. Um, So I’m gonna put this back and we’re actually gonna take one of these skulls with us and go find the skulls that we have of the extinct giant beavers. So you can see those right together and we will eventually make it to the world’s most complete fossil giant beaver.

Lucas: Let me paint another picture here because we, this looks like somebody’s garage, but a garage that they would’ve spent a lot of time in and there are long, low tables in it. And, uh, more of the filing cabinets around the walls.

I’ll also state for the record. One of these cabinets is labeled dinosaur bones. yes. You know, I need a career change.

six year old me would’ve been losing his mind.

Heather Lerner: This entire cabinet is dedicated to our giant beaver to the most complete, and this holds a copy of every bone in it. So these are,

Lucas: It’s the best jigsaw puzzle!

Heather Lerner: It is. It’s actually really fun to put together. Done that a few times. Um, so this is the first copy that we ever made. Um, and it is made from creating molds of each individual bone. Um, except for the feet we did those all together. So many little bones in a foot, right?

And if you go find a giant beaver in another museum, it’s potentially a copy of ours because we cast it in the 1980s, and then many museums got copies from that. Right. And then we also created a new copy of it a few years ago with the help of two researchers who were then at the Virginia Museum of Natural History who came here and we made all new molds because molds deteriorate over time.

And so do copies, um, and some things had changed. We needed to [00:18:00] modify the skull a little bit because it had been built up. On our original, some clay had been added and we needed to change that because after finding more skulls, we knew that some of the sutures were wrong. Okay. So in your skull, you have different bones that come together to form that, right?

And they fuse together as you grow and stop growing. Once you stop growing, they fuse together. So those lines we guessed at based on modern beavers. And it turns out when we found war fossil skulls, we needed to change that because they were not correct. So this entire cabinet here is a copy

Lucas: and I’m gonna look, it would’ve been plaster of Paris.


Heather Lerner: yeah, probably.

Lucas: Yeah. And now we’re working in, in silicone or, or 3d,

Heather Lerner: We’ve done two different things. One is that we are using silicone molds, um, and then casting in resin. Um, the other thing is that, so if you come and play our giant beaver escape game, which I know you would love, um, you actually get to handle some of the copies and those copies used to be cast, which are very good for research, right?

They are very high quality, scientifically accurate. The kind of thing I will study off of rather than bother the specimen itself. And one of those disappeared. So just a few weeks ago, we 3d, scanned and printed copies because now we can always reprint, but the molds deteriorate over time. And in fact, we don’t have the molds here, so I can’t just make a backup copy. Now that that one piece is gone. Huh? I’m gonna get into this cabinet here.

And I should be able to show you the one that we actually sequence.

So in here you’ll see that we sampled for DNA. [00:20:00]

Lucas: whoa.

Heather Lerner: So anytime we do something, we put a note in.

Lucas: So round plug, meaning that you drilled a very, very small, uh,

Heather Lerner: almost like a core sample. Exactly. So, so

Lucas: then you would have a tiny rod of, uh, fossil material. , uh, not just like drilling it out and then sort of taking the fossil saw dust, but

Heather Lerner: rather a whole take the actual plug. We do grind it up then, but we do take the plug . And one of the reasons you’re trying to do that plug is that you wanna get past the really hard enamel on the outside of the teeth into the soft protected material where the DNA should be preserved. And what’s very cool about teeth is that it’s one of the few places in your body that you retain pluripotent cells. So cells that can become anything. Cells that are very open to suggestion. They generally don’t do anything else, but you know, whatever they do in your teeth.

Um, but if you need cells that are activate-able, that’s a place to get them. And what that does mean is that they are less, um, less bound up. And so that DNA can be super good. And it means that there’s a lot of DNA in there. So that’s why we’re aiming for teeth.

This I believe is the one that we got DNA out of, which is somewhat surprising. You see, we sampled it on the 14th of May, 2015, Micha Ahmed and Jacob Paris and me, they get their names written out and I’m just HRL. So that’s the one that we got, uh, two thirds of the genome from, the mitochondrial genome.

Yeah. And actually this is the ulna, the tooth did not end up working. Okay. And what what’s interesting about that is we did a lot of work trying to figure out exactly where we would have the most, the highest likelihood of, um, getting DNA and what turned out to happen is that wasn’t so useful?

The most important thing was [00:22:00] it was collected more recently, which meant that it had had less time out of its deposition environment to accumulate damage or to deteriorate. So like I said, we’re trying to keep things so that stable temperature and humidity, because when you have fluctuations is when DNA gets damaged.

Well, we don’t really have stable, uh, temperature and humidity here. And so over time, things just deteriorate. Um, so one of the things we’re really actively working on trying to improve conditions so that things will be useful for longer. So the most recently collected specimen is the one that worked , but I know an awful lot about DNA preservation. So let’s take this one over.

This is the tooth.

Lucas: That’s the tooth?!?

Heather Lerner: That is one tooth. Yep.

Lucas: This is the left encisor. It is the size of a banana

Heather Lerner: Big banana. Thin, but very long. Yeah.

Okay. So let’s just do this for a second. We want you to see the modern beaver, right. You remember with the little chompers, right? Okay. And then let’s put that next to the giant beaver.

Lucas: This skull came from a four foot 50 pound beaver, and yet it is, um, the size of two clenched fists, I would say.

Heather Lerner: Well, it fits in my outstretched hand. Right?

Lucas: , you know, the base of the skull is at the base of your Palm and the tip of the nose is at your index finger.

Yeah. And then this one.

Heather Lerner: Like we don’t watch it like a football here. You’re looking at this and thinking with the size of teeth like that, I could take down some big trees. Right? Are you [00:24:00] thinking that?

Lucas: I am well, I am now.

Heather Lerner: Okay. Well, you shouldn’t be thinking that cuz that’s wrong. I was mean right? This is, it was, it was exactly. Okay. So what’s really interesting about this, um, is that they probably didn’t have that, um, same.

They didn’t have that same tooth structure. They probably were not able to chew off pieces of wood. They were not chopping down trees. We have two lines of evidence that tell us this oh three, maybe number one. We have not found any pieces of wood, fossilized wood, with the marks of giant beaver teeth on them.

That’s, you know, absence of evidence is not, right, evidence of absence. Sure. So we’re gonna hold off on that, but we haven’t found that, um, we haven’t found any big dams or lodges in context with a giant beaver. Okay. So that’s more absence of evidence. Um, the other thing is that you can, like I said, these organisms hold a signature of their environment. You can look and see what they were eating. I could figure out what you are eating from the stable isotopes in your hair.

Lucas: Okay. That was significantly less creepy than I thought it was going to be, talked about plugs drilled from teeth.

Heather Lerner: I’m not, I’m not gonna take a plug of your teeth. that’s Nope. I’m really far more interested in the fossils, but if we wanted to and people have done this, they have looked at the signature of the foods people are eating from their hair and fingernails and you can see where like what your favorite fast food is because different fast food places are getting their beef from different places.

Lucas: Wow.

Heather Lerner: And that holds the signature of the [00:26:00] environment, the food, it was eating the place it was living.

Lucas: You literally are what you eat.

Heather Lerner: Yes, you are. that? Yeah, that is correct.


Heather Lerner: So, um, there was a really neat study that came out in 20, 20 same year as our, um, as our DNA study and they were looking at a different species of beaver, not so giant about two-thirds the size of the modern beaver.

And that’s a Dipoides, is the genus. And they were curious, what was this, this animal eating? And then they were comparing it to Casteroides, to our extinct giant beaver and to Castor the modern beaver.

What they’re doing is trying to figure out, um, there are different options for what these species could be eating, right? You’re in an aquatic environment. And we have evidence that Dipoides was in an aquatic environment. It, um, evidence of, uh, chewed, chewed wood. So that’s pretty strong, right?

Find Dipoides, you find some things that look like maybe it was a lodge? They could be eating bark, they could be eating, you know, the, the layer right underneath the bark, the stuff that has good nutrients in it could be eating that. So they could have been eating any of the other plants that around them. We know that they’re vegetarian or we assume they are given rodents, um, long evolutionary history of being vegetarian, um, or herbivores. So they could have been eating mosses and lichens and other things that would be in this Tundra area where the species was found, they could be eating trees or shrubs.

They could also be eating the, like the leafy vegetation that would be in the ponds. Right. So macrophytes, that green fleshy stuff. And so you can look at the carbon and nitrogen isotopes in those different types of plants. And then you can look at the tissues of [00:28:00] that animal and see how they compare.

And there’s a lot of other science going on behind there. Right? You don’t just lay down exactly what you’re eating your body, modifies it a little bit. And so you have to do some corrections and things, but from this, they were able to show that it does look like Dipoides, I know we’re taking a detour here to a different species, but it is important and relevant.

You can cut it if you need to , but it looks like that one was basically a generalist in the sense that yes, it could do some woody plants and those macrophytes. Pretty cool. Yeah. They were also using information from Casteroides and this is where it gets really interesting. doesn’t look like they were eating woody things.

Their signature shows much more strongly in the macrophyte. So then you start looking at those teeth again and thinking, okay, so not having the super strong orange piece on those teeth, maybe they really weren’t doing that. Maybe they weren’t cutting down trees. Maybe that absence of evidence is because they’re, they weren’t doing it.

So start looking at those teeth again, when you see this, um, the front teeth have this sort of, um, inverted V shape or like a little, little mountain shape and where they, the two teeth meet is almost like if you’re gonna cut a piece of paper and you just open the scissors a little bit and sort of push it at the paper and slice that paper apart.

Like this is a good slicing thing. And you think about reeds, you think about grasses? You wanna cut those? You just slice right through it with this kind of a tooth structure. Cool. Right.

Lucas: So rather than having a metal knife in its mouth, it has, uh, a pair of bone scissors.


Heather Lerner: Amazing. it also [00:30:00] has these wonderful molars and those look like nice grinding teeth. They’re not in my opinion, that dissimilar from the modern beaver. Um, but modern beavers are also gonna be eating that, um, fleshy vegetation as well. So in the summer, when you can get it, you wanna eat stuff that has the highest reward value.

So the most nutrients and, you know, we need fiber. Everybody needs fiber, but you don’t want it all to be fiber. Like you don’t wanna go heavily on the tree side, if you don’t have to really go for the fleshy stuff, if you can get it. So they’re eating the fleshy plants, but then they’re caching those twigs underwater to keep them cool. And to last over the winter. And that’s why we have beavers today is that they have that adaptation of being able to make it through those long dark winters. And when they create those dams and they create bigger bodies of water, those bodies of water don’t fully freeze over so they can maintain an open access underneath the water.

It can hide their food down there, cause all the green plants they’re, they’re not edible. They’re not growing in the winter. They’re covered in snow. But if you can keep ’em in your underwater refrigerator, all winter. You can survive because they don’t really hibernate. They kinda slow down, but they do need to eat throughout the winter.

It’s kind of a bummer that the giant beaver doesn’t seem to have been using trees and building dams and lodges because that probably is a major contributor to its demise.

It wasn’t able to handle the warming of the climate. It wasn’t able to handle the drying out of the climate. It needed those big waterways, you know, the, you find a lot more Casteroides in the areas south and around the great lakes. So they just, they weren’t able to make it [00:32:00] through that changing climate. And so they did become extinct. The end of the Pleistocene.

There’s another really cool adaptation, but I think we should go see the most complete fossil giant fever.

Okay. Let’s do it.

Moving up

Lucas: We weren’t in the museum?

Heather Lerner: We were behind the scenes now we can go to the public side.

Lucas: Let’s go over here. Pass the whooping crane pass. Oh,

Heather Lerner: I’m gonna say it.

Lucas: Uh, the, the, the most complete skeleton of a fo-, shoot.

Heather Lerner: Yep. World’s most complete fossil giant beaver.

Lucas: World’s most complete fossil giant beaver. I got it.

Heather Lerner: You got it.

Lucas: I think,

Heather Lerner: it is really nice to say,

Lucas: ah,

Heather Lerner: here she is. Wait,

Lucas: what? . Ah,

This one right here.

Heather Lerner: I love this orientation. She is coming right at you.

Lucas: Oh, she?

Heather Lerner: Yep. We can tell from her pelvis and her size that she’s a she. So when I first got here, she was turned sideways and you could just see her from the side, which you haven’t even seen yet.

Yep. And then we were doing some, you know, renovations, new exhibit kind of stuff. This whole exhibit is all new signage, um, designed by our students. Um, and we rotated her. And for the first time we saw her coming at us and we said, “Oh, that’s the way you need to approach her. You need to think about a giant beaver approaching you, or you approaching a giant beaver.”

Lucas: Yes.

Heather Lerner: And there she is. This is her.

Lucas: This is her.

Heather Lerner: Yep. This is not a copy. In fact, we don’t have an assembled copy. I showed you that cabinet again, it’s all in different boxes so that we can get them out and lay them out and, and measure [00:34:00] different things and look at them.

Right. Like I said, taxidermy, not so great for scientific study. Also mounted, specimens, not so great for scientific study. It’s a little hard to see every single piece and rotate it and measure all the things you wanna measure. We have done it, you know, for the Mastodon, we did measure all the different parts so that we could determine the size of it.

Question is scale. I, uh, yes. Lifting up that femur a little different, but, um, so we actually have her on exhibit in most places you will not see. Well, I mean, nowhere else will you see. The world’s most complete, complete fossil giant beaver , but we do have her right here on exhibit.

Lucas: Incredible.

Heather Lerner: You made a comment before about seeing the skull of an animal and thinking, gosh, it seems bigger when I see it alive. And if you think about it, very few people are just the size of their bones. In fact, no one is except a skeleton. You have all sorts of muscles and tendons and cartilage and fluid and a whole layer of fat and skin all over the top of those bones.

So just that alone is gonna add, you know, depending on the particular organism, half inch to an inch all the way around. So it’s really much bigger when this animal was fleshed out and we have some great illustrations, um, Corbin Rainbolt was a student here and he is a renowned paleo artist. Um, and he did the artwork for our, for this exhibit when he was a student.

And he has also continued to work with us afterward and done drawings for us because lots of times I need something that shows the difference between a modern and an extinct organism. And so I, I need them in context with each other. I need a particular [00:36:00] orientation and, and Corbin does that kind of work.

In fact, what I’m wearing is . . .

Lucas: Hey!

Heather Lerner: A giant beaver mini skirt.

Lucas: She’s been here the whole time!

Heather Lerner: Yep. Pretty cool.

Lucas: That is fabulous, Heather!

The giant beaver – paleo-art on a pencil skirt!

Heather Lerner: And you can get your own on red bubble. You can also get a t-shirt and other thing, a notebook or whatever. exactly you day before. I dunno. You may have to buy a couple different sizes.

 The discovery

Heather Lerner: So this is the world’s most complete fossil giant beaver. It is not however, the type specimen.

Lucas: I got it wrong. I thought that’s what it was.

Heather Lerner: It’s not. The type specimen is no longer in existence. It was lost in a fire. And this one was also almost lost in a fire. So these are all these stories are all wrapped up together.

um, she was found by some farmers in the Eastern part of Randolph county in Indiana. They were opening up a ditch to drain a swampy area. It was locally known as “The Dismal.” And the contractor who was doing this work came upon the skeleton. And this is neat. It said, “On account of its standing in its natural position and its wonderful tusks, it awakened a desire to save all the parts that might be found.”

That was written by Joseph Moore in 1890 when he described this specimen. This contractor found this animal and thought this doesn’t look like anything I’ve seen before. look at those giant chompers, right? Yeah. And they wanted to know what it was.

They brought the skull into town, the farmer whose property, it was brought it into town and started asking around and nobody knew what it was. No one had seen [00:38:00] anything just like this before. And you remember that giant football in my arm for that skull. If you found that you would be wondering what the heck as well.

So no one knew what it was. Somebody said, put it up in the window of the bank. Someone coming in or out will surely know. So they put it up in the window of the bank. No one knew. Finally someone said, take it down to Earlham college. If anyone will know it’ll be Joseph Moore. So they brought it down to him and he immediately said, “Well, I am not totally sure. However, I do believe it’s a giant beaver. But the giant beaver has been described from a fragment of tooth and jaw. That’s all that’s ever been found of it before. And you have a whole skull school. Is there anymore?” And they said, “Oh yes, the whole thing, it’s right there!” So they went back. The contractor knew exactly where it was.

They dug the entire thing up. It is seven eighths complete, as I’ve said. And so you can look at her and you can see a slightly different coloration. where you can see what’s real. And then that darker color, right, that other matrix that we use to fill in the parts that we’re missing so that you have what looks like a full skeleton here.

But very little of that is that dark color, right? There are a few of the vertebra and the neck there. Um, there’s a little bit of the, of the shoulder blade, um, a little bit in the toes, but for the most part, this is a complete skeleton.

So she, Joseph Moore purchased her with some of his own money, some money that was donated and brought her here and she’s remained here ever since. Like I said, two different sets of molds have been made from her so that she can be shared throughout the world and be studied more easily.

Um, [00:40:00] but we did almost lose her in 1924. Um, she was in Lindley hall, which was where the museum was housed at the time. And that night, um, just after I wanna say midnight, um, the building went up in flames. The floors were wood and they had just been oiled. And so it went up hot and fast.

Students were awoken by the sounds of this and ran out of their dorms. Students worked in the museum then just as they do today. And they knew the incredible value of this giant beaver. And they ran into the burning building, picked her up and carried her out. We have a, a copy of a letter written by one of those students after spending hours doing this, went back to his dorm room and sat down and wrote home to his mommy and poppy to tell them about what happened.

And to say, I just, I don’t think I can settle down to sleep. I don’t know what the rest of the semester’s gonna be look like, gonna look like. This building burned. This building also housed the registrar and all the records.

A lot of the work was really saving the, the specimens of the museum. So we do, we are the caretakers for an Egyptian woman, um, Ta’an, she’s, um, she’s mummified and she is in the museum here. She was rescued. The giant beaver was rescued and you know, anything else they could get their hands on.

In 1952, Jim cope, reestablished this museum in the space that we have here. And she was put back on display. So there was about 25 years when she was off exhibit, um, or at least not in the Joseph Moore museum. Right. So she’s back on display.

Lucas: Wow, incredible.

Heather Lerner: So our students now know the most important specimens [00:42:00] that we have and the order that you would save them. they also know. To be very careful with their own selves and do not die in a fire. that fire, the 1924 Linley fire did claim the life of at least one firefighter. And, um, it was deemed to be arson.

There are several hypotheses. One was a disgruntled janitor who had been fired, who would’ve known the schedule of the oiling of the floors. And would’ve known the best time to take the whole building down. Um, another hypothesis, since all the registrar records were burned, was that it was a student hoping to erase their record.

And we don’t know to this day, who did it. Wow. I wish someone’s diary with a confession would be found, right? Yeah.

Lucas: That is an incredible story. Part of the reason that I knew I had to come up here was I’m writing a book for fantasy authors, essentially. And to tell them that, Hey, there was an Egyptian woman and a giant beaver who survived a fire in Indiana in the fifties like that is, uh, you can’t write this stuff.

Heather Lerner: She, she has some pretty incredible history and some real, real champions who would risk their own lives to save her.

Type Specimens

Heather Lerner: So you were asking what a type specimen is.

Yeah. And when I referenced how Joseph Moore said, “Well, I think this is a giant beaver, but the description of giant beaver is based off of the fragment of a tooth and a jaw.” That’s it. He then turned around and wrote a paper that described this specimen, but he could not name it because it had already been named as Casteroides ohioensis from that tiny little bit.

Lucas: Wow.

Heather Lerner: So Joseph Moore has an amazing paper that is really descriptive about this entire skeleton, but it is not the type specimen.[00:44:00]

Lucas: Type specimen is,

Heather Lerner: the individual for which the species is described from. We define this species to be something that has these particular morphological. Which are based on a tooth and a jaw.

Gender Bias in Museum Collections

Heather Lerner: What’s very interesting is the extraordinary bias in museum collections, which mirrors the collecting tradition that museums are built upon, which is the collecting tradition of white men going and documenting the world around them and primarily collecting male individuals of species and describing species based on the males. So the vast majority of type specimens are males. The vast majority of specimens and collections are also males. And that holds true even for species and you might be thinking, okay, well the males have bigger tusks. They’ve got antlers.

They’re very pretty, they’re flashy. Right? We’re gonna collect them. They’re also the ones that may be more aggressive. So they may be more easy to catch because they might approach you and you might be able to shoot them or catch them or whatever. Even controlling for that. We do not collect in equal numbers, males and females

what I think is really important is to be able to describe the variation within a species. And when you boil it all down to the type, the one, the original you miss what makes up the beauty of species, which is the unique traits, the range from light brown to dark brown that you see in the pelts, from the length of the fur, from the lengths of the tails, from the behavior, there’s so much beauty and, um, flavor that when you [00:46:00] focus on a type specimen, you lose.

The Giant Beaver Horn

Heather Lerner: What you didn’t know about that I said I was gonna tell you before, and then I didn’t is a very cool feature of the giant beaver.

Lucas: You’re giving me the eyebrows. And from what we talked about before that didn’t get eyebrows. I know this is gonna be cool.

Heather Lerner: You look inside of the modern beaver and you can see the brain case. Yes. Right. You look inside and you can see there’s an opening in the nose. Right. You have openings in your nose too, for obvious reasons. Um, there’s some breathing purposes going on there and there’s maybe some more airspaces in this skull.

It’s a little hard to see because. Skull, and it has an exterior bone structure. This giant beaver. In my other hand, you can see is because of the way it’s been preserved. You can see a lot more inside and you can see there’s a big opening in here. Big open space in there where the spine would’ve. That?

That is where the spine, you can see on the, on the, where the vertebra come off, that hole, the, the FRA at the back of the skull. So there’s a big opening in there and you can sort of stick your finger down in and see, it goes pretty far down. And then you can look up its nose and you can see in the modern beaver that opening stops maybe an inch or so in, in the giant beaver.

There are all of these pockets of openings and they connect way back in here into the skull. So that brain case opening is very small compared to this other giant opening in the front of the skull. But there’s this big opening behind the nose, reminiscent of whales of things that communicate underwater, things that have [00:48:00] resonant chambers for making big sounds. I mean, we don’t know for sure.

But it really kind of makes you think that the giant beaver was making a lot of sounds clicks and words, and maybe big booms and maybe it was resonating in there. We don’t know the soft structures that would’ve been in there because those have not been preserved someday as the Tundra thaws, we’re going to find a fully fleshed, giant beaver.

And the first thing I wanna know is what’s inside that big. What do those structures look like? There is a researcher, Beth Rinaldi, and she got a 3d. She got a CT scan of giant beaver skull and was not this one, not this one and was able to print, essentially print that empty space and turn it into a horn so that she could play the sound of the giant beaver horn.

And when we go downstairs, I’ll see if I have that recording on my phone and play it for you. Because I went to her house once I heard that and I happened to be passing through Kansas, which, where she was at the time I sent her an email immediately and said, I’m going to be there in December. Can I come to your house?

and she said, sure. so I showed up and I’m coming to your house. Exactly. And she played the giant beaver horn for me.

The Book of Extinction

Lucas: Stay tuned for more about how this ice age giant becomes a D&D monster, but I just want to briefly tell you how you can take it home to your table. The giant beaver is one of more than a dozen Plieistocene megafauna appearing in Book of Extinction, a bestiary of extinct species for 5th edition coming to Kickstarter in March of 2023. You can get the most recent playtest release of Book of Extinction by joining the Mage Hand Press Patreon family of nerds at Patreon [00:50:00] dot com slash m f o v. The giant beaver appears alongside the giant short-faced kangaroo, the glyptodon, and the saber-toothed tiger. You’ll also meet prehistoric lycanthropes like the dire werewolf, the cave werebear, and the weremammoth. That’s Patreon dot com slash m f o v.

Patron or not, you can get the first three monsters in the Book of Extinction – the passenger pigeon, the great auk, and the Tasmanian tiger – right now at Scintilla dot Studio slash extinction. Pay what you want for it, and anything we earn will be donated to the Center for Biological Diversity to support their protecting endangered species and wild places world wide. All those links are in the description.

Dr. Lerner & D&D

Heather Lerner: So I figured at some point you were gonna ask me about my experience playing Dungeons and Dragons, which is not vast, and what I thought about this animal as yeah. You know, a real creature and what its special traits are. And also as a, as a magical creature. So I’ve been thinking about that for a little bit, and I really think that ability.

That sound ability is pretty cool. And I mean, just as an actual living creature, the ability to make those sounds. And, and first as I, you know, my thought processes have, have changed over time. Um, you know, like I was pointing out before with ASOS, we used to think they were tail draggers. Now we think that their tails were upright and we used to think they were maybe just green and scaly, you know, we think, oh, they could have been all different colors.

Right. They could have had lots of different. And we’ve changed our opinion of what the giant beaver looked like. I’ve been understanding more, um, about her and I think a lot about her impact on the environment around her. And I was thinking if you’re not cutting down trees, you’re not building dams.

You’re not building lodges. [00:52:00] You’re not like the ecosystem engineer of the modern beaver. What are you really doing anyway? but I do think. that she was keeping those ponds clear of vegetation. If she was eating a lot of reeds and macrophytes, all that pond, weed, those ponds, weren’t those dense places that you think of.

Now, when you’re thinking of a wetland where you can’t get up to the water, there’s so much vegetational around it and they get filled in pretty quickly. I bet with her insatiable appetite. She was really moving a lot of vegetation out of there. And I would bet with those incredibly strong back legs, she could have been moving stuff out of the bottom of the ponds and keeping them big and open.

And she could have been making sounds that would’ve carried in these big spaces and maybe through waterways as well, because she would’ve been clearing the waterways. Cuz I was thinking you make a sound underwater in a, in a stream, in a pond. It’s not gonna carry very far, cuz there’s so much stuff around in there that we’d just soak up that sound.

I maybe not, maybe she was moving things around and creating a space that would let her sounds travel. So I think if she were mythical that her sounds, if they were clicks and words, Might do slashing damage. I think that maybe if it was more of a resonant chamber, she could be making a boom that would flatten you.

I think that she’s got some powers with the, with her massive airspace.

Lucas: When did you start playing? What’s the what’s.

Heather Lerner: What, what kind of a part of your life at first? Okay. I first played a game in graduate school with some friends [00:54:00] um, and I think maybe it was maybe a more traditional game, definitely more traditional than my next game ion.

It was, I don’t know anything about it. Sure. This is my level of experience, but what I do know is. Fighting random things. I just wasn’t, I wasn’t super into it. I felt like I wasn’t sure I wasn’t doing it right. I didn’t know what I was doing. There was so much fighting and there was like weapons and I wasn’t really into that.

And then I became director of the Joseph Moore museum many years down the road. And I took students to New Zealand for a study abroad program. And one of my students was a DM who is also a great natural historian. loves organisms loves knowing about the natural world and when he understood or when they understood what I really like, they were able to design a game that was perfect for me, which was, I just wanna hang out with the animals.

I want to talk with them. I want to do things with them. And if there are animals around, I am into it. but when they’re not like, okay, when’s the good stuff happening. So in this game, my goal was to make friends with every animal we found. And so everywhere we went, I asked if I could look for animals. I asked if I could talk to animals.

And I got very lucky with some early roles and we met a giant bear and I rolled a. And so that bear became part of our group. that bear, every time you did a check, that bear was still fully part of our group. every time I happened to get a great role and we approached a town with this giant bear yeah.

And needed to get in [00:56:00] and the gatekeepers like, well, um, uh, no, right. I don’t think so. And we, right. And then I said, I’m sorry, we don’t have a bear. That’s uncle. And it turned out that my deceit or whatever that’s called, I rolled really well on that. And so then uncle Jim was just uncle Jim came into the town with us and stuck with us.

okay. And that made a great game. So McGee Catlett was that student and they did an incredible job as a, as a DM for me. And it got me very interested in playing or, and now my husband, who’s a physics professor here. Just started running a game for our family. We have three kids. And so he’s been learning how to run a game so that we can adventure together.

Lucas: Thanks for listening to Making a Monster: Extinction. Many thanks to Heather Lerner and the Joseph Moore Museum at Earlham College for providing this behind the scenes tour and opening my eyes to the hidden possibilites in paleo art and DNA reconstruction. The extinction of megafauna tells us so much about how we relate to the natural world, and I’m excited to add what I learned from this trip to the Book of Extinction.

Do you like maybe things that get going on ways to get involved with the museum work that you’re doing, that you want people to know?

Heather Lerner: Yeah, I would say one thing is you can see her yourself. We are just off I 70. So if you’re ever traveling across the country and many people. You’ll be on I 70. Yeah. So we’re pretty easy to find we’re open every afternoon from one to five except Tuesday and Thursday year round. And we also have an escape game that features the giant beaver and your goal during the escape game is to rescue the giant beaver from a fire.

And you actually get to handle some of the copies of her bones in the course of the game. And some of the newspaper articles about these big events, the fire and so on, are part of that game. [00:58:00] So the game is all built on real science, real history surrounding the giant beaver. So when you play the game, you learn more things that are actually real, which is pretty cool.

We that’s start doing. Yeah. Yeah. So you can do it in another game setting. Uh, escape games are pretty fun. And then we also have an escape game, uh, that features Ta’an, um, our Egyptian woman who’s mummified here. Love to have you follow us on social media and check us out. Upcoming research: we are always looking for more, more ancient DNA projects to work on. We’re also working on stable isotopes of modern songbirds and looking at migration patterns and what, what makes songbirds choose to move or feel forced to move, and how can we figure that out based on what’s in their feathers.

Lucas: Now’s a great time to hit that follow button and leave a five star review on your podcast. App of choice. It’s a small thing, but it really does help new listeners discover the pod. If you want to support The Book of Extinction and endangered species conservation at the same time, you can visit the project’s landing page at scintilla.studio/extinction. That’s S C I N T I L L A dot studio slash extinction to download the first three monsters in the book. You can pay what you want for them. And whatever we earn from that sale will be donated directly to the Center for Biological Diversity.

You can also keep up with the project by joining our email list where I’ll be sharing more of the incredible, true stories that surface through this research or follow this podcast for more episodes of Making a Monster: Extinction.

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