‘Prehistoric Planet’ Defrosts Strange Animals Of The Ice Age

IRA FLATOW: This is Science Friday. I’m Ira Flatow.

Koalas with the body of a lion, elephants the size of your dog, gigantic, eight-foot-tall sloths– no, these aren’t creatures found in a new novel. They walked our planet a million years ago, during the Ice Age. And that’s the focus of the new season of Apple’s Prehistoric Planet series, which uses the latest paleontology research and photoreal CGI to recreate ancient creatures from the past.

So far, it’s focused on dinosaurs. But now it’s taking that same approach to the fantastical and strange-looking animals that walked the tundra and enormous deserts of the Ice Age. Here to thaw out the new research featured in the show are two of its scientific consultants– Dr. Darren Naish, paleontologist and author in Southampton, UK, and Dr. Emily Lindsey, associate curator at the La Brea Tar Pits and Museum in Los Angeles, one of my favorite places. Welcome back to Science Friday.

EMILY LINDSEY: Thanks for having us.

DARREN NAISH: Thanks. Good to talk to you again.

IRA FLATOW: Darren, we had you on the show a couple of years ago to talk about the science in the first season of this show, which, as I said before, focused on dinosaurs. What were you excited about with this season going into the Ice Age? What did you want to do differently?

DARREN NAISH: That’s a great question, and a hard one to answer. As a fan of animals in general, when I knew that we were going to be making an Ice Age series, even the Ice Age animals that are the most household names of these creatures that you can think of– woolly mammoths– who hasn’t heard of a woolly mammoth?

That’s not an unfamiliar animal. Most of us have grown up with exposure to the fact that there were such animals. But that doesn’t mean that there aren’t amazing things to learn about it, like what does it actually look like in life? And how does it behave?

So I knew that even building the super familiar animals– the woolly mammoth, various of the species of saber-toothed cats– just building those familiar animals was going to be a formidable challenge. It was going to be really great fun. We were going to learn a lot from it. And because mammoths are elephants, because saber-toothed cats are cats, these animals actually present a real special challenge in term of bringing them to life, something that, obviously, we had to work incredibly closely with the CG animators at Framestore because the familiarity of those animals, in fact, makes them even harder to reconstruct accurately and realistically than animals that are actually pretty remote to us today.

If you’re talking about a tyrannosaur, very few people today have got a real good idea of how a tyrannosaur might look as a living animal. But if it’s a cat, you get that slightly wrong, and immediately it just doesn’t pass the sniff test.

So building those animals– I knew that was going to be tremendous– a challenge and fun. And then there’s all these obscure creatures, these less familiar, very extinct weirdos relative to the Northern Hemisphere perspective, animals like the giant marsupials from Australia, various extinct animals from tropical Africa and South America, various weird, obscure sloths, various giant marsupials, giant short-faced kangaroos– could not wait to get to grips with those because experts have competing ideas on what they look like, how they moved, how they behaved, how we would actually bring that together and build them. I knew that would be a fun challenge. And the results speak for themselves. I’m super happy with how all our animals look.

IRA FLATOW: Emily, do you find evidence in the La Brea Tar Pits of ancient animals?

EMILY LINDSEY: Oh, yes. We have thousands upon thousands of animals from the Ice Age that are preserved in the Tar Pits here in Los Angeles. Interestingly, Los Angeles was actually a little bit cooler and a little wetter than it is today. So it was really a lush savanna ecosystem supporting multiple species of giant ground sloths. We have seven species of cats here, all the way from the American lion, which is the largest cat that ever lived, multiple species of saber-toothed cats.

We have, famously, dire wolves, which are our most common large mammal we find preserved here, mammoths and mastodons, camels and horses and bison. It was an incredibly rich ecosystem of Ice Age LA. But as Darren mentioned, we also have hundreds of species of birds and reptiles and amphibians and mammals that are still alive today, and many of which still live here in the LA Basin.

IRA FLATOW: OK, so the season opens with a bang, with a woolly mammoth giving birth to a baby in a brutal snowstorm. What did it take to survive as an animal during this time?

DARREN NAISH: One of the key things about the Ice Age world– so the Ice Age is properly known as the Pleistocene. It’s about a 2-million-year-long section of geological time– is famously, we are talking about a time when the far north and the far south of our planet is colder than it is today. There are much larger ice sheets, obviously, colder temperatures.

But you are still talking about a world that does have tropical and subtropical and temperate zones as well. And a key thing that we cover in the series is that with all of this vast amount of water locked up in ice, it meant less atmospheric water across the whole of the planet, which means lower sea levels and a far drier atmosphere. So things like savannas and deserts were larger during the Ice Age than they are today.

So yes, you’ve got these animals that are adapted for extreme cold in multiple different lineages of– particularly of big mammals. In particular, you saw animals with extra layers of fat and thick woolly coats and so on among groups that today we associate with the tropics. Mammoths are not a separate group of animals from elephants. They are a kind of elephant.

So you’ve got cold-adapted elephants– likewise for big cats– cold-adapted cats, cold-adapted deer and bear and so on. But then in the tropics, you’ve got many animals that are more adapted for dry climates– so animals with unusual noses because they are doing what they can to conserve water.

And the final thing I have to add– an important point about Ice Age animals is the Ice Age is so recent. It ended about 11,700 years ago. That’s really recent. Everything alive today, with a handful of exceptions, a handful of very recently evolved animals– we had salamanders and such– everything alive today was alive in the Ice Age, including us. So you’ve still got to imagine that everything alive today is also present in Ice Age times.

IRA FLATOW: I’ve also heard that the VFX team referenced cave paintings to get the fur right on the animals. Is that correct?

DARREN NAISH: That’s basically right. So we are Ice Age animals. We saw a lot of these animals when we were alive. And people of the Ice Age, some of whom were incredibly skilled and experienced artists, illustrated a lot of these animals when they were alive. And in some cases, they provided us with information that we otherwise wouldn’t know.

So the main thing that they gave us is patterns of pigmentation. So on some animals, there’s various extinct deer and cats– mammoths and rhinos, also– where the cave artists showed precise distributions of spots and stripes, gave us some idea which parts of animals were dark, which were light, what fur length was like. There’s even some clues to posture, like when does a woolly rhino have its tail in the air, stuff like that? So yes, we took account of all of that and built it into our models as well.

IRA FLATOW: Darren, we, obviously, think of the ice and snow during the Ice Age. That’s what we call it, the Ice Age. But the show spends a lot of time in deserts, in tropical regions. What were those like?

DARREN NAISH: Yeah. So the fact that the Ice Age goes from ’round about 2.6 million years ago until around about 11,700 years ago– that’s enough time for a lot of change to happen. We also know– we’ve known for centuries that this span of time that we term the Ice Age actually consists of multiple very cold spells and then very warm spells.

And during the interglacials, the warm spells, you’ve got to imagine that somewhere today that we consider fairly cool and temperate might actually have been a little bit warmer, drier. I’m, obviously, in Southern England. And during some of the interglacials, there were animals here that today we think of as animals of tropical Asia, the Middle East, parts of Africa. So there were giant elephants here. And there were hippos. And there were lions. There were lions of a kind of tropical sort here in England.

So from our perspective today– a completely different world. So it’s a super interesting world, a really more diverse world. And the key take-home point for me about the Ice Age is, in a way, the diversity of animal life in the Ice Age is kind of what our planet’s meant to be like.

When we think of giant animals today, if you’re in North America, you’re thinking of– you’ve got moose and you’ve got two Big bear species, a couple of other big deer and whatnot, and bison, obviously. But alongside those, there should be armadillos the size of small cars, sloths bigger than the biggest bear. There should be several species of elephant living wild in North America.

And I can say similar things everywhere, everywhere in the world except Antarctica. All the major landmasses had this amazing assortment of animals that are no longer with us at all. So we’ve got a very impoverished view of megafaunal diversity. Megafauna is anything above about 40 kilos.

IRA FLATOW: That raises the question, if you found the same species on completely different continents, how did that happen?

DARREN NAISH: Yeah. So many animals that today we associate with a specific region in the Ice Age were able to spread widely around the world. The lion is a great example. We mostly think of lions as an African animal. They were also lions in the Middle East. But in the Ice Age, there were lions throughout the whole of Asia, throughout the whole of Europe, throughout North America. And some lions probably got into South America as well.

This is partly due to the appearance of land bridges. So if sea level is going up and down according to how much water is locked up in ice, lower sea levels mean that areas of land that today are separated by sea were connected during the Ice Age. So the most familiar example is Beringia, which is the area that connects Alaska with Siberia. If that’s dry land, animals can, obviously, pass relatively freely between North America and Asia.

EMILY LINDSEY: Yeah. I want to add to that– actually, to both of Darren’s points. So I completely agree with the point that we have an impoverished view of– and understanding of megafaunal diversity. From the present day, 50-plus million years, the normal state for planet Earth has been to have large animals– chiefly, mammals– on all the ice-free continents on Earth. And it’s only very, very recently in geologic time that that hasn’t been the case.

And these migrations– they started happening millions of years ago. So a lot of species that we actually associate with other places, maybe Africa or Asia or South America, actually started out in North America. So camels would be one of the key examples here. In North America, we tend to think of camels as very exotic animals. But they actually evolved here in North America. And then–

IRA FLATOW: Really?

EMILY LINDSEY: Yes. And then 10 or 15 million years ago, they crossed a land bridge into Eurasia and became modern camels. 3 million years ago, the Isthmus of Panama formed. They crossed down into South America and became llamas. And then they went extinct here in North America at the end of the Ice Age.

And so what you see happening during the extinction event at the end of the Ice Age that wiped out more than 2/3 of the large mammals on Earth is a real range contraction of species that, as Darren mentioned, used to be really widely distributed– lions, camels, horses, elephants. And now they’re only associated usually with one continent or one particular geographic region.

IRA FLATOW: This is Science Friday from WNYC Studios. We’re talking about how the new Apple TV Prehistoric Planet season brought Ice Age animals back to life. Let me ask you a bit about that because I know you study how ecosystems collapse. How did the Ice Age end?

EMILY LINDSEY: Well, so that’s something that scientists have been debating for more than 70 years now. And it’s still a point of contention. But I think if you take a zoomed out view of it, the story of the last 50,000 years or so is the story of one megafaunal species, Homo sapiens, systematically replacing most other large mammal species on Earth. So humans were definitely a key player in this extinction event on a broad brush scale.

Now, I think the question is, how did we do it? And I think the show does a good job of communicating the stresses that animal populations experienced due to these very significant climate changes that were happening. And so how did climate and environmental change intersect with growing human population and technology and resource consumption to cause this ecosystem global tipping point where we go from the age of mammals to, really, the age of humans?

IRA FLATOW: Are you saying that we hunted these large animals out of existence?

EMILY LINDSEY: I think it’s more complicated than that. When scientists talk about humans being responsible for the extinction, they’re usually thinking about hunting. But I don’t think that Homo sapiens hunted down every species. Dozens and dozens of species went extinct at the end of the Ice Age.

We do have good evidence of humans hunting, in some cases on large scale, particular species– different types of elephant species, mammoths. We know they hunted horses and camels. There are other species that we have absolutely zero evidence of humans hunting.

So I think there’s a combination of hunting and other impacts. And something that we discovered here, based on research at the La Brea Tar Pits that we conducted a couple of years ago, is that, at least in this region, there’s a particular tool that humans were able to use to completely transform the ecosystem. And that was fire. And we discovered that right at the point when large animals stop getting trapped at the La Brea Tar Pits, there is this order of magnitude increase in fire on the landscape. And those fires were very likely ignited by humans.

IRA FLATOW: Where are we in our general understanding of the Ice Age now? You mentioned new research that you’ve discovered at La Brea Tar Pits. But in general, compared to past decades, what do we know more now than we knew years ago?

DARREN NAISH: In many ways, this is the golden age of Ice Age studies for a bunch of reasons. It was the perfect time to make a TV series devoted to these animals and their world because there’s so much amazing new science that’s being done on them.

So for example, DNA studies– there’s this new information that’s helping us work out how these animals are related to one another, and even aspects of their life appearance. Some of their adaptations to the cold we’ve learned about thanks to recent genetic discoveries. We know, for example, that woolly mammoths actually lacked specific genes that are related to feeling cold. And they actually had– they were genetically adapted for being OK in the cold.

And a slightly sad subject– but global warming that we are causing is resulting in the increasing discovery of Ice Age animals in Siberian and Alaskan permafrost. So we are finding, year on year, more permafrost bodies, nearly complete, beautifully preserved Ice Age animals that give us so much information on what the animals actually look like. This is a great time to make a TV series about these incredible animals.

IRA FLATOW: Well, I want to thank both of you for taking time to be with us today– fascinating stuff. Dr. Darren Naish, paleontologist and author, and Dr. Emily Lindsey, associate curator and excavation site director at the La Brea Tar Pits and Museum– you can catch the new season of Prehistoric Planet on Apple TV.

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