The Life Scientific: Tori Herridge

0:00Tori Herridge:This BBC podcast is supported by ads outside the UK. Pop quiz. What's in your kid's lunchbox? At Whole Foods Market, they've already done the studying. Over 300 food ingredients are banned from their shelves. No hydronated fats in the peanut butter and no high fructose corn syrup in the cookies. And for sandwiches, there are no synthetic nitrates or nitrites in any of their deli meat. So you can pack lunchboxes with peace of mind. Get back to school ready at Whole Foods Market.

1:05Tori Herridge:Once upon a time, about 100 ,000 years ago, in the chilly depths of the Ice Age, multiple species of elephant roamed the Earth. They travelled the globe, adapting habitats to their needs and evolving to accommodate new pressures. Actually, remarkably similar to our own evolutionary history. And this is what fascinates today's guest, Tori Herridge, a senior lecturer in evolutionary biology at the University of Sheffield and a seasoned science broadcaster. Fascinated by fossil elephants and their evolutionary parallels with humanity, Tori has spent much of her life studying such relics and the sites where they were excavated, trying to establish facts about fossils that are tens of thousands of years old.

1:48Tori Herridge:During her career, Tori has so far discovered dwarf mammoths on Mediterranean islands, retraced the groundbreaking Greek expedition of a female paleontologist in the early 1900s, and even held an ancient woolly mammoth's liver. As she put it, it was really stinking as it thawed, but for someone like me, it simply doesn't get much more exciting than that. Dr Victoria Tori Herridge, welcome to The Life Scientific. Thanks, Jim. I'm going to have to ask you first up, a woolly mammoth's liver. How do you get your hands on something like that? Well, you have to wait for it to thaw. Let's go back to the beginning.

2:23So if you go to the permafrost in places like Siberia, in that permafrost you still find remains of ice age beasts. So that includes woolly mammoths and one such frozen carcass. So not a fossil, a frozen carcass, flesh, fur, bone, was discovered in the northern Siberian islands, brought to Yakutsk. I was there for its necropsy, its autopsy, if you like. And as part of that, over several days, it thawed. When it had thawed enough and we could get into the abdominal cavity, there was a liver in there. So that was all filmed for a TV documentary. But prior to that, all of my interactions with mammoths, fossil elephants, have been with fossils.

3:05Bone has started its journey towards being stone. And so when you've got the skeleton, and it's hard and it's heavy. It's not fleshy. It's not pliant. That's right, you can't study the organs at all. It's dinky, but yeah, that was just amazing.

3:19Tori Herridge:Well, I do want to come back to that autopsy or necropsy. Necropsy, I guess, is the technical term, but let's face it, autopsy work, right? But as I mentioned just now, your research focuses on fossil elephants. What exactly does that term cover? So today we have three species of elephant, two in Africa, the forest elephant and the savannah elephant. And we have the Asian elephant. but go back just 30 40 50 000 years 100 000 years and you have many many many more species all of which have now winked out and that's within that elephant family tree so a mammoth is just a special kind of elephant and then actually go slightly further out you have elephant cousins like mastodons stegadons and it's big it's got a trunk it's got tusks you know it's basically in that family tree they're all gone now we've only got three left and when we talk about the ice age what period are we discussing here ice age is one of those terms that we use like really sort of willy-nilly but um i guess the ice age basically is now we are in an ice age we've got permanent ice at the north and south pole for now and that started about two and a half 2.6 million years ago and so that last period which we call the pleistocene and the holocene or the quaternary is broadly speaking what we think of when we say the ice age within that period there are colder periods where it was really cold and the ice at the north and the south poles expanded into huge ice sheets.

4:36And then there are also warmer periods like today when those ice sheets contracted.

4:40Tori Herridge:I think you mentioned this earlier, but when we talk about the ice age, there is this tendency to imagine these fossils being unearthed from the permafrost in vast snowy tundras. Some of them are, of course, but they are scattered all around the world, aren't they? I mean, some of the most incredible specimens have been found here in the UK. Yeah, yeah. I mean, we've got a very rich fossil history in the UK. And we are a country that was defined by those ice sheets, right? They carved out the amazing landscapes of the Lake District, the Scottish hills, Wales, you know, those valleys we see there, they are remnants of ice sheets that carve through the land.

5:16But in warmer periods in the past, like today, it was a very hospitable land and lots of animals and some humans lived here. And even in the colder periods, in the southern ends, you'd get, you know, mammoth herds, wolves, reindeer, that sort of thing. And wherever those ice age gravels are, you will find fossils. Whether there is a cave that may be escaping, scoured away by an ice sheet, there's a good chance you will find remnants of fossils. Fossil hippos in Yorkshire, for example, in a previous warm stage. Imagine that.

5:43Tori Herridge:There were even some fossil elephants found close to where you grew up. Yeah, so I'm from Essex originally, and you get gravel pits there. Lots of excavation for sand and gravel, and in those pits, ice age fossils come out. And all of those sites are fossil elephants. the Orford mammoth, the Avery elephants, you know, it's all there. OK, then, Tori Herish, let me take you back to your childhood. You were born in 1980. As you say, you grew up in Essex with your mum, dad and three sisters. Were you interested in the natural world as a youngster? I guess so. I mean, there was encyclopedias. I used to love the primates pages in that encyclopedia, definitely.

6:18There are pictures of me at zoos and things like that. But I don't have any kind of overwhelming sense of myself as like a young natural historian. You know, I didn't really think of myself as somebody who was a scientist until much, much later.

6:29Tori Herridge:Well, certainly your trajectory shifted somewhat during your A-levels because, you know, you were more on the arts side. But you then shifted from arts to science. So what happened? I think it was always history and English that excited me. Science felt very prescribed. But there was a moment, I think, around GCSE where I suddenly realised there weren't any answers. And it coincided with understanding about how the world had changed and this idea of ice ages. and that really captured my imagination. Suddenly it felt creatively interesting. And it's still, I mean, this is a prevalent attitude, isn't it, that somehow people perceive science as not one of the creative subjects, you know.

7:04Yeah, exactly. And that moment, that was a real kind of, like, it was like a light bulb moment to me.

7:08Tori Herridge:Well, you got your intervals. After school, you went off to University College London to study anthropology. How did that go? So I did it for a term. And by the end of the term, first term, I realised that I could not do all of the science modules I wanted to do. And so again, I said, OK, by this point, I'd clearly started down that path where I just couldn't leave the science alone. And so I made the decision then to switch. So I switched anthropology to biology. So that's a love of biology. Was there anything that sparked your particular interest in elephants? Well, I was allowed very kindly.

7:42They let me take a master's level course in human evolution as part of my undergrad. And during that, there was a seminar series focused on humans as part of the wider environment, particularly humans, if you like, as animals. And all these parallels between what humans were doing and what other animals were doing, what elephants were doing at the same time in the Rift Valley. And those parallels just suddenly made me think, this is fascinating.

8:09Tori Herridge:It was while you were studying in London, first as an undergraduate and then again during your master's in taxonomy and biodiversity at Imperial College that you landed this part-time job that really had a huge impact on your future. So I've always had to have a part-time job and one job that came up was this part-time job at the Science Museum and that really did change many, many things for me because it was such an extraordinary experience and the training was second to none. You're an explainer. I was an explainer. That's a fantastic job, isn't it? To take people around. You worked on the...

8:42So in those days, when I worked there, you'd basically rotate around the galleries, interacting with people, doing the kind of hands-on experiments, but also doing science shows.

8:50Tori Herridge:And as we'll come to later on, that was your introduction to science communication. Yeah, and it was a pretty... It was a baptism of fire, I'll tell you that, but oh my goodness. It was, as an experience, second to none. Fantastic. Well, Tori, after you completed your Master's, You then decided to do a PhD in evolutionary biology back at UCL, University College London, with a thesis on dwarf elephants on Mediterranean islands. Tell me more. Yeah, so we talk about elephants. Elephants are the largest living land mammal. They have been the largest group of land mammals for a significant period of time.

9:26And so really, they define everything that we know about what it means to be a big animal. What works as a big creature? What does it mean in terms of metabolism, in terms of life history, in terms of the way your skeleton holds up your frame, the way you move? All those things are basically defined by the elephant. But elephants are also really weird. They are part of this group called the Afrotheria, which contains elephants, Cyrene, like dugongs and manatees, and also little things like hyraxes. This is like, you know, rock rapid things. And elephant shrews, bizarrely. So disparate.

9:58Tori Herridge:Interesting. And their little evolutionary lineage is something that really is about 65 million years or so distinct from everything else from the end of the Cretaceous. So they're very unique, evolutionarily speaking. So how much about being an elephant is due to it being big? And how much about being an elephant is due to it being an elephant? It's an interesting question. And it's really fundamental because of that aspect related to body size, which is probably the most fundamental character in biology. So interesting thing about elephants, when they become isolated on islands, which they have done many times in the past, they always evolve, become smaller.

10:33And so that's a really interesting thing to think about. Why does this big animal that is supposedly the epitome of the large animal niche on the mainland, why do they always stop being big? What does that tell us? And the great thing about it happening on islands many, many, many times is that it gives you a natural experiment. So the idea of that PhD was to do just that. Use that natural experiment to investigate aspects of what it means to be big.

10:58Tori Herridge:And learning about why they were small can tell you something about elephants today as well. Yeah, that's the idea. I mean, and so I'm talking about Sicily, about Malta, about Crete, about Cyprus. And some of those elephants were tiny. Some of them were a metre tall as adults. It's incredible. Yes, you think of elephants small, but not the size of a large dog. Yeah, it really is. I mean, and their babies were puppy sized. Incredible. After your PhD, you got this great research post at the Natural History Museum. And by this point, you'd clearly got the bit between your teeth when it came to dwarf elephants of the Mediterranean.

11:35Tori Herridge:You put together a new project to fill in the gaps in their evolutionary story. Yeah. So one of the questions I wanted to answer was why do dwarf elephants become small? It's a big question. It's still ongoing. and it became clear to me very very quickly starting my PhD that I was never going to be able to answer that question because once you dug into the detail that there was no decent baseline data on fundamental things like how old these elephant fossils were for the simple fact that this material had mostly been excavated in either the 19th century or the early 20th century and the agendas were different people were just collecting things from a kind of curiosity sake You're kind of documentation of the natural world.

12:16And so they weren't really paying attention to the context in which these fossils were found. Things that if you were to do it now, you'd do very, very differently. And then, of course, they didn't have the techniques available to them that we have today in terms of dating old stuff.

12:30Tori Herridge:So tell me about some of these scientific techniques that you used on these samples to try and extract information. So we have two problems. problem number one my material mostly comes in the mediterranean on these islands from pretty warm humid places and in those situations things like collagen dna don't survive very well and so even if we had got relatively young material so stuff younger than 50 000 years it was often hard to radiocarbon date it because there wasn't anything organic left to date right but actually the other problem was that most of this material is actually older than 50 000 years which is as far as you can go radio carbon dating just based on the half-life of carbon and so as a result you've got to use a different set of techniques now a lot of my material came from caves which have lovely layers of salagmites and salactites and those you can date with uranium thorium dating which just uses the half-life of uranium and the way it breaks down the right thorium which is a down site longer than yes exactly right you can go go a lot further back and so actually it's pretty good until about 300 000 years or so alongside that though we have sites outside and there's no salagmite so on those in sort of sandy deposits for example or sedimentary deposit we would use optically stimulated luminescence dating which is a mouthful osl which is basically dating the last time the quartz in the sand or in the sediment lost or sunlight she dig into the depths pick out a sample from the darkness and then you can basically see the last time the quartz itself was exposed to sunlight and that's also fairly go up to about 300, 250, 300 ,000 years or so.

14:06And then we can also use another technique directly dating teeth and bone called electron spin resonance dating, which is something similar with the electrons trapped within crystals within things like tooth enamel. Pop quiz. What's in your kid's lunchbox? At Whole Foods Market, they've already done the studying. Over 300 food ingredients are banned from their shelves. No hydronated fats in the peanut butter and no high fructose corn syrup in the cookies. And for sandwiches, there are no synthetic nitrates or nitrites in any of their deli meat. So you can pack lunch boxes with peace of mind. Get back to school ready at Whole Foods Market.

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15:17Tori Herridge:I gather your fieldwork involved following in the steps of an earlier explorer who visited those Mediterranean islands in search of fossil elephants in 1904. the paleontologist Dorothea Bate. Yeah, so she is renowned for walking up to the front desk of the Natural History Museum at the age of like 19. This has been like, you know, 18, 99 or something like that, and demanding a job. And she didn't leave until the crater of birds let her in and things like this. They never gave her a job, not for years, not for years, but they did pay her piecemeal and they did also support her in things like applying for funding to go on excavations.

15:53And as a young woman in her early 20s, she went first to Cyprus and then to Crete in 1904-5, right? And on Cyprus trip, she found these incredible, tiny, like one metre tall dwarf elephants. Incredible. So her material is in the collections. I want to go back to the sites that she found those fossil elephant teeth for so I can see if I can take the teeth. And amazingly, in those collections, in the archives, we have her diaries, we have maps that she took with her, her little like handwritten notes and lines drawn on the maps, you know, just spine shivering stuff, you know, it's great. and so you could literally walk in her footsteps you could go back and find it and sure enough we did

16:29Tori Herridge:She sounds remarkable, in fact this is perhaps a good moment to talk a bit more about pioneering female paleontologists because Dorothea Bates wasn't the only one. No, and that's when I was trying to imagine what she was like what it was like for her to do that you start to create these stories, these very simple stories in your mind so I would imagine Dorothea Bates, this brave pioneering woman on her own in Crete, so remarkable so unusual and so I google you know Edwardian explorer wearing what you know kind of thing just to kind of get in my head what she might have been wearing and in doing that do you know what popped up a picture of a woman called Harriet Boyd Hawes who I'd never heard of before and she was running an archaeological site in Crete in 1904 1905 so I was like oh okay there was another woman on Crete at the same time as Dorothea Bate and she was doing some archaeology turns out Well, Dorothea Bate went and visited her at that site, made friends with Harriet, who was the first woman to direct, she was an American woman, to direct an excavation in Greece.

17:30And she was excavating a site called Gornia, which is a big Minoan town. And on that excavation, she was working with a woman called Edith Hall Dolom. And Edith and Dorothea Bate climbed a mountain together. So three women doing remarkable things. And the more you looked into it, the more I looked into it, the more I realised that this was not an unusual situation. Now, to me, that was a really important thing. Yes, it exposed my own ignorance, it exposed my own willingness to tell a cliched story. But also what it told me was that I had been led to believe that this was a rare situation. But actually, it wasn't unusual, even in 1904.

18:10Tori Herridge:And those stories just haven't been told? No, and it's not just the stories themselves. Because I mean, how many people can name any scientists who are working in 1904, right? There's loads of people we've forgotten. It's more the idea of it, the idea that there were many women doing this. And in 2013, Tori, you co-founded the organisation Trowel Blazers. That's T-R-O-W-E-L Blazers, which is all about sharing stories of precisely the sorts of pioneering female scientists that you mentioned. And it is so important, isn't it? I think so. To me, I had one goal for Trowel Blazers. I wanted people to go onto that website and I wanted them to start scrolling.

18:47There are so many stories to be told. And we crowdsource them. We invite people to submit their own favourite stories from history and from the present day. So you can just look in one glance and go, there are a lot of women doing this stuff. And the reason why I think that's important is about resetting the idea of what was normality.

19:02Tori Herridge:I know that communicating science and making it accessible is incredibly important to you, which is where your broadcast career comes in. We mentioned the woolly mammoth autopsy documentary in 2014. How did you end up working on that? That was one of those serendipity situations. So my friend happened to make television programmes and he said, let's make a taster tape. And I thought, all right, then might as well do that. And it just happened that that taster tape landed on the desk of a senior person at Channel 4 at the moment at which they'd already greenlit the mammoth autopsy. So they were already looking for a mammoth expert.

19:37Tori Herridge:Oh, well, there you go. Exactly, right? And so that was one of those things that it was just luck. So you end up working on this documentary, this mammoth autopsy. I gather during the filming, this particular mammoth you're dissecting and studying, you nicknamed Buttercup. Yeah. Why? Because when her carcass was found in these islands of the north coast of Siberia, when they cut into her flesh, dark, bloody ooze came out. And they were like, it's flowing blood. And so she was referred to by my Russian colleagues as the bloody mammoth. And so like the bloody mammoth this, the bloody mammoth that, which of course as a Brit has all kinds of pejorative terms around it right and so I just it was my like jokey way of contrasting that because poor buttercup and also it came from the fact that we know from other studies of mammoth remains that mammoths weren't just eating grass they were eating the beautiful flowers that grew on the mammoth step including buttercups and you learned a lot from this autopsy didn't you all sorts of information from her health to her offspring to how she died yeah I say well yeah I mean with a kind of caveat out that I guess we'll never know for sure but she was 47 thereabouts when she died we can tell it from her teeth but also from the growth increments in her tusks she probably had 11 children in her lifetime again you can see that from the growth increments in the tusks tusks are just basically overgrown incisors like your front teeth in a mammoth and when your teeth grow you lay down the layers in them incrementally and they mark periods of ill health or periods of stress in your life as well so these increments grow and grow and grow you can count them as lines like growth rings in a tree and periods of time where you're malnourished or you're ill or you've got an extra burden on you when you're pregnant exactly when you're pregnant or breastfeeding then you basically tend to lay down thinner lines and so you can count those she probably had 11 calves one of them maybe might have died before weaning you know these are wonderful stories she was in good health when she died she had a good layer of fat on her she probably died in the sort of spring summer because she didn't have a thick winter fur anymore you know so you get this picture of these various things.

21:41Tori Herridge:It really is, as you're describing, it really is detective work and forensics. I remember this investigation in particular did fire up the public's imagination. In fact, there's a lot of talk at this point, both in the scientific world and in the media, about the possibility of cloning a mammoth. Yes. Now, how would that work? Well, at that point, it was very different. Now, the story has moved on considerably. So the planned approach right now for creating a mammoth-like creature, which is also sort of aka bringing back the mammoth, it would be to tweak some Asian elephant DNA to adjust parts of its genome, parts of its genetic code, to make it more mammoth-like and get the mammoth-like features that would make an Asian elephant embryo grow into something that looks like a woolly mammoth.

22:30Tori Herridge:I know you've been very open about your concerns around this. In fact, a few years ago, you even turned down an offer to be an advisor to what's called a de-extinction company. What was it that worried you about that? Yeah, I just, I don't think that any of the benefits that are cited hold water. And the risks that are involved don't balance. There's no need. I can't see any need for a simulcrum of a woolly mammoth, a woolly elephant on the Siberian tundra. Now, the people who promote it do see a need. I don't think the evidence stacks up. And if the evidence doesn't stack up, then there's absolutely no justification for playing around with experimentation or living elephants because that's what it is.

23:12Tori Herridge:Okay well let's get back to your story. At the same time as your presenting career was kicking off you were still working for the Natural History Museum and in 2015 you had your first child. Yes that was a very busy time. Well in 2017 you made a big decision to leave the Natural History Museum and focus on broadcasting for a while. I mean, that is the other side of science rather than doing the research. Communicating the research to a wider public is so vitally important. It's really, really, really important. But your role in that is very different. For me, being on both sides of the fence was a very interesting experience.

23:46Tori Herridge:Well, certainly the lure of research was still strong with you because in 2021, you went back to the Natural History Museum to take up a research fellowship. and it allowed you to refocus your attention on fossil elephants via their teeth. Yeah, the teeth were something that had really, really got under my skin. And the thing I was interested in really is that elephant teeth are massive, right? You know, imagine how big an elephant's head is. When they're an adult, their wisdom teeth take up almost the entirety of each of their jaw quarters. One wisdom teeth on each side at the bottom and one on each side at the top.

24:21Four teeth. They're the size of bricks. So on the surface, you know, they're molars, but they don't look anything like our molars. And so I wanted to understand how elephant teeth fitted into this broader pattern of mammalian tooth evolution because of that big story about what does it mean to be big, right? You know, what does that mean? And I wanted to see whether they did indeed fit the pattern. And basically the data does show that they just do the same thing that mammals do in a kind of really exploded way. And that was really satisfying.