Short Wave - The Life And Death Of A Woolly Mammoth

Episode Date: February 19, 2024

Lately, paleoecologist Audrey Rowe has been a bit preoccupied with a girl named Elma. That's because Elma is ... a woolly mammoth. And 14,000 years ago, when Elma was alive, her habitat in interior Alaska was rapidly changing. The Ice Age was coming to a close and human hunters were starting early settlements. Which leads to an intriguing question: Who, or what, killed her? In the search for answers, Audrey traces Elma's life and journey through — get this — a single tusk. Today, she shares her insights on what the mammoth extinction from thousands of years ago can teach us about megafauna extinctions today with guest host Nate Rott. Thoughts on other ancient animal stories we should tell? Email us at [e-mail] and we might make a future episode about it!See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

You're listening to Shortwave from NPR. Lately, Audrey Rowe has been a bit preoccupied with a girl named Elma. Well, Elma is her nickname, short for Elma Yuja. It's a name given to her by the Healy Lake Village Council, the Mendus Cheag people, a tribe native to interior Alaska. The way that they translate it is Hella Lukkin. It's a name that's given affectionately towards things that are interesting, looking, but not necessarily beautiful. So it's like a name for like your ugly pet dog, for example.

How do you know my dog's ugly and hella looking? Oops. It's true. Audrey's a paleo-ecologist and Ph.D. candidate at the University of Alaska Fairbanks. And she's been studying Elma's tusk because Elma is a woolly mammoth. So Elma lives about 14,000 years ago. and her tusk was found at one of the oldest, if not the oldest, uncontroversial archaeological sites in Alaska.

Uncontroversial because there's no dispute that humans were present there too. The site is littered with human tools. And this is interesting because as far as we know, humans only overlapped with woolly mammoths in interior Alaska for about a thousand years. Somewhere in that one thousand year period, Elma lived and died. Audrey's now studying data from Elma's Tusk to track the massive 1,000-kilometer journey she and her herd took through Alaska and northwestern Canada, and she's hoping to figure out

just what did Elma in. Everyone always wants to know. Is it the humans that did them in or not? Humans are to blame for plenty of extinctions around the planet. But this area has an extra little little twist, which is that this was the time of great change in terms of the habitat itself. That's right. There could be another culprit, the end of the ice age. 14,000 years ago, Alaska was rapidly changing. Things were getting warmer, things were getting wetter, and that would have allowed trees and shrubs to start migrating in a little bit, creeping in in some of the moisture areas like riverbeds.

The habitat was changing in a way that mammoths like Elma just weren't built for. And humans were starting to pop up in the area as well. So it's sort of a chicken and egg thing. Like, are they there because you've got tons of mammoths? Did the mammoths go extinct because humans were hunting them? Or is it the other way around? Were humans able to penetrate this area because it was getting warmer, wetter, just more hospitable to humans? Right. Because eventually, I mean, like mammoths, right, go extinct. Eventually, mammoths do go extinct. Yeah. And not too long after this period, actually, in Interior Alaska. Today on the show, we trace Elma's grand life and journey through a single tusk.

And we take our best guesses at who or what killed her. I'm Nate Rot. You're listening to Shortwave, the science podcast from NPR. Okay, Audrey, let's talk about our girl, Alma. Where did she live? Like, what was she about? What was she about? Yeah.

From our movement studies, we found that she, She was born somewhere in what is today the Western Yukon, sort of on the edge of where she really could have lived because there were ice sheets guarding interior North America at that time. There was the Cordillaran ice sheet and the Laurentide Ice She spent about a decade wandering around and then about halfway through her life. She underwent a long movement westward for about two years of her life. traversing all the way to interior Alaska, where she spent the rest of her life and mysteriously died,

even though she, as far as we know, was pretty healthy, according to the chemicals in her tusk. And she was at the peak of health in terms of her age, too. So she was about 20 years old. I like to think of mammoth timelines as being sort of similar to humans. So they mature at around 15 years of age. kind of like humans, you know, puberty? It took me a little longer, but yeah, right around that. More or less.

But my advisor did a similar study of a 30-year-old male mammoth. He underwent a lot larger movements, especially after the age of 15 or so after puberty. So from that, we're starting to infer from these two studies that mammoth movements and structure of behavior would have been similar to modern elephants. So today modern elephants live in matriarchical herds, at least the females do.

Whereas when modern male elephants go through puberty, basically, they're kicked out of the matriarchical herd. They wander on their own trying to find mates in different herds, and they just move around a lot more. Huh, okay. When I was reading the sub your study, I was wondering, is it normal for a mammoth to move that much? Or, I mean, was Elma just kind of having like a hot girl summer?

You know, I didn't know. Yeah, it does seem kind of strange. This two-year movement pattern, she does not return to where she was. We can only infer things. We can never know why she, and presumably her herd, decided to take this long movement westward. And so what we infer is that maybe resources started to dry up in the Yukon. and they went out looking literally for greener pastures and found them in Alaska. Tale is oldest time, always looking.

Grass is always greener on the other side of the ice sheets. So how did you learn all this information? I mean, how were you able to infer and figure out her movements in everything, given that she died 14,000 years ago? Yeah. So elephant and mammoth tusks kind of grow, like stacked ice cream cones. It's like every day a new layer is added.

A new cone is added to the top of the stack. And as they're building this stack, each day, they're laying down material from the nutrients that they ate. As they're walking around, they're picking up basically bits of their environment from the food they're eating, from the water they're drinking, and then laying it down in this permanent record that is their tusk. So we split open the tusk,

and we analyzed the ice, all the way from the tip, which would have been close to birth to the end of the tusk closest to the mouth. And that end of the tusk would have been really close to, if not the day of her death. Whoa. Yeah, so by doing this isotope analysis along that whole length, we learn a lot about location she was in because you are what you eat and your food has a signature of where you were when you ate it. And we learn a lot about her nutrition. So we know that, uh, we know she didn't starve to death. That's for a certain. Cool. All right. So I, I'm curious about this tusk thing because it, I mean, it almost reminds me of like dendrochronology, right? How we like can bore into a tree and

learn something from all the different rings. So it's kind of the same. You basically can look through this almost like history of the, of the mammoth, right, by just looking at these layers, uh, that stack up on the tusk. Yes. Exactly. Cool. You can learn a lot from a tooth. Yes, I love it. You mentioned that Elma was roughly 20, right?

She'd just gotten out of her, like, teenage years. Yeah. But she was totally healthy when she passed away. So how did she die? Yeah. We can't rule out, like, some sudden disease that hit her really fast and knocked her down. There's no smoking gun at Swan Point. In Europe, in Siberia, there's a couple examples of, like, almost literal smoking guns

where you have human tools embedded in mammoth vertebra or ribs or whatever, clear evidence of human hunting. We don't have anything like that in Alaska, but we have means and motive. So the exact same types of tools that were used in Siberia are the ones that were found in the Swan Point site in Alaska. It's very good evidence that the same people who lived in the Asian side of Beringia walked over and then lived in Alaska in short order before their tool culture had time to change. We can't for sure say that Elmo was hunted, but there's a lot of evidence that it was possible

and that it was desirable. Yeah. Would have been a big package of meat for them. Her tusk was actually used as a tool itself. Oh, wow. So a piece of it was removed, and there are a lot of indentations on the outside of the tusk, which means that it was probably used as an anvil,

just to hit objects against it. Wow, interesting. So it's not only just, you're not just potentially killing a woolly mammoth because you want to eat, it's also that you want to be able to use the tusk, for example, as a tool. Right. Yeah, ivory was a super-use material.

Huh. Okay, so you can't definitely say, like, you're not going to run in a murder conviction for humans, right, on this. But is there another contender? Is there another thing that you suspect could have killed Elma? Well, adult mammoths didn't have really many viable predators. I mean, that's the whole point of being big. You see this evolution of large herbivores throughout Earth history is just herbivores grow bigger and bigger and bigger and bigger and bigger.

And they're just outgrowing their hunters. How does she, how does her story and kind of what you've learned from her, how does that weigh into this bigger debate about whether or not it was humans versus climate change that kind of eventually led to the demise of woolly mammoths in North America and across the world? Yeah, a lot of large megafauna would have been suffering because of the Holocene, because of the climate changes that happened, the bigger ones that just take so much longer to reproduce especially. I mean, like I said, mammoths don't hit puberty until 15-ish. Yeah. And their gestation period is 22 months. Holy moly. Whoa. Right. Yeah. So if they suffer losses, they don't recover in a hurry.

if you look at what survived the Pleistocene into the Holocene in Interior Alaska, there's some really interesting similarities between what survived. So Alaska used to have horses, right? Not anymore. Alaska used to have Saiga, which are these like little antelopes that still exist in like Mongolia. Yeah. The step of Eurasia. Those are both grazers.

And the things that do survive are things like, moose and caribou, which are browsers, which means that they eat like twigs and things, not grass. That's part of the reason why I always say that mammoths probably wouldn't be able to live on this in this habitat today. But humans helped, probably. So we don't have an answer to this large gaping kind of... It's a complicated story. No, there's no singular answer. Yeah. Can I ask a question that just like I always, I work on climate change usually and I ask this all the time, right?

But like, why does it matter today that we have an answer to what happened to Elma and to woolly mammoths in Interior Alaska? Well, a lot of conservationists are seeing this on their own that the animals that they're trying to keep alive today, but is most difficult, is larger animals, like, you know, white rhinos. Yeah. So I think studies like this are just evidence of that happening throughout Earth history. kind of informing us of where we're going by looking into the past. Yeah. That's super cool. Well, Audrey, I am very into the story of Elma.

I'm very into the idea that bully mammoth tusks are just like a big stack of ice cream cones. I will never look at a tusk the same way again without thinking about that. Thank you, Audrey. It's good to meet you. Bye. Before we head out, a quick shout out to our shortwave plus listeners. We appreciate you. and we thank you for being a subscriber.

Shortwave Plus helps support our show, and if you're a regular listener, we'd love for you to join us so you can enjoy the show without sponsor interruptions. Find out more at plus.npr.org slash shortwave. This episode was produced by Margaret Serino

and edited by our showrunner Rebecca Ramirez. It was fact-checked by Britt Hansen. Gilly Moon was the audio engineer. I'm Nate Roth. Thank you for listening to Shortwave from... NPR.