Instant Genius - Hyenas with Prof Adam Hart

Episode Date: March 7, 2022

Prof Adam Hart explains why zoologists find Hyenas so fascinating, why they're so unlike other mammals and how having a few hyenas around isn't such a bad thing. Once you’ve mastered the basics with Instant Genius, dive deeper with Instant Genius Extra, where you’ll find longer, richer discussions about the most exciting ideas in the world of science and technology. Only available on Apple Podcasts. Produced by the team behind BBC Science Focus Magazine. Visit our website: sciencefocus.com Hosted on Acast. See acast.com/privacy for more information. Learn more about your ad choices. Visit podcastchoices.com/adchoices

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delivering digital precision with analogue warmth. So you can experience exceptional sound at home. Music just as the artist intended. Visit name audio.com. to learn more. From BBC, science focus, this is instant genius. A bite-sized masterclass in podcast form. I'm Daniel Bennett, the magazine's editor. And today we're talking about hyenas and their tense relationship with the human world. I'm joined by Adam Hart, a zoologist and broadcaster who presents Tooth and Claw, a BBC World Service Discovery series that examines our preconceived ideas about

nature's most fearsome predators, and how we live with animals that can and occasionally do eat us. You can catch the soul live or find it on BBC sound now. Hyenas, traditionally speaking, I think culturally in the West, we see them as kind of cackling, perhaps cruel scavengers. Is that the correct sort of perspective on them? Well, it kind of is and it isn't. So it depends what we're talking about when we think about hyenas. So normally when we're thinking about hyenas, I'm maybe speaking for people here, but my guess is most people are thinking of the kind of hyena that you would see in the Lion King, for example, which is spotted hyenas.

I mean, that's what most people are thinking of. There are a few other species. So there's the brown hyena, which is sometimes called the Strandwolf, which lives down in the southern Africa, a really beautiful-looking creature. There's the striped hyena, which has a really large range, actually, goes across into Asia and India. there's a creature called the Ardwolf, which eats termites, so is a member of the hyenas, but very much not like the others, quite a small creature, but the spotted hyena, which is just sort of archetypal hyena, the one that people are thinking of from Disney.

They do scavenge. Yeah, I mean, they do scavenge. They're really effective scavengers, and they're wonderful carcass breakers, so they get in there and tear stuff up and crush bones and things. But actually, in quite a few parts of their range, they are very, very effective predators. and in some parts of their range, they're almost exclusively predators. In fact, when lion sort of researchers have been observing these things and so on, it's very common to see lions actually tanking prey from hyenas.

So hyenas will be sitting in the background and everyone thinks they're waiting to scavenge. Well, actually, they've been chased off their own kill by a larger animal. So, yeah, they're much more predatory than people think, particularly in some parts of their range. They seem to be an animal that every zoologist I've ever spoken to, has a kind of a really, you know, they really admire the hyena or they, find them particularly fascinating. What is so special about the hyena? I think, I think, you know, part of it is because people don't like them very much. So there's this, there's this, there's often a sense of kind of, you know, standing up for the underdog, which, you know, in hyena's case, is actually incorrect

because they're more closely related to cats, weirdly than to dogs and not particularly closely related to either. But yeah, I think there's a little bit of that, you know, it's the reason why I stand up for wasps and stuff. You know, there's a sense of like, well, A bit more to it than that. But of course, with hyenas, you've got this really weird thing going on where the females have a sedo penis, for example, which they give birth through. They can form these really big social groups, these big clans that can be up to sort of 150, and they've got all complex kind of things going on. Yeah, they've got this whole scavenging thing going on, which is really interesting. And again, it's the sort of underdog of ecology, right?

Everyone thinks about predators as being the cool thing. But, of course, with hyenas, you've also got the fact they're predators as well. So it's kind of, they tick a lot of boxes, I think, if you're a zoologist, and they do some weird stuff. They're the underdog, and they do these kind of strange ecological things. So I think, yeah, you're right. I've never come across a biologist that will bad mouth, I eaters. And actually in the show, in Tooth and Clore, one of the great scientists that you interviewed, she put it quite well, I think.

How does she say? She said that there's so many opposites in them compared to the rest of the animal kingdom. Yeah, they're sort of these contradictory creatures. And actually if you describe them, you start to describe something that's kind of ugly. And then you look at it and they sort of are in a way, but they're also not. And it's this kind of, there is a tension with hyenas that I think is quite interesting. And, you know, they're kind of scary. So you see a hyena yawning.

You really start to get an idea of just how powerful those jewels are. I remember watching a brown hyena, which are gorgeous looking things. And it suddenly yawned and it was like looking into this. We were sort of on a truck. it was kind of behind a fence. And it massive, massive mouth suddenly opened. And we're looking at at this teeth. And I was there with a group of students. And we're all kind of going, oh, cool, it's a brown hyena. And then it yawned. And there was just silence. Everyone sort of inwardly digested just how fearsome these kind of jaws were and stuff. So yeah, there's something about them, I think,

that draws people. So you touch on it there. So they, you know, they're not cats. They're not dogs. What is a hyena? What is it related to? They're actually related. So this is where things get a bit strange. So there's a little group of mammals, the genets, the civets. There's a fossa that lives in Madagascar that form a little sort of a group of mammals. And actually, the hyenas are a kind of offshoot of them. They're most closely related to the civets, the African civet. And you can see that weirdly in the ardwarf, which is the sort of the fourth hyena that people forget about, the one that eat to termites, which is quite small. It has a civet kind of looking build about it. You lose that kind of impression once you get into the spotted hyena. But that's where

they're from. And at one point, the hyenas were much more diverse than they are now. They've been around for about 20 million years or so. And we've lost a few along the way. They sort of branched off into two groups. There's the sort of bone crushing groups and these other groups. And they had quite a bit of diversity. And now we're sort of willowed back to the fall. But in the past, there were hyena is the size of lions. They're particularly fearsome, extinct hyena, which I've got to be, got to be honest with you, would be an impressive thing to see,

but you do want to see it from the safety of a vehicle, I think. But, yeah, that would have been quite something. So, yeah, we have a sort of depoporate hyena for one of these days compared to what we had, but still four good-looking species that we can have a look at. I'm going to say something really stupid now, I think. I think at all similar to some of the creatures like bad, that we have in the UK.

Is that a complete myth? They're kind of, they're not, it's tricky with mammals, because they all kind of break off into sort of different kind of groups, but so they're not in the same group, but equally they're there, they're within the sun of carnivora. And they're within a group of carnivals called the Philoformies, so they are more closely related to cats than they are to dogs. Despite their appearance, I mean, some of them, like,

so the brown hyena, I say, is quite dog-like. The spotted hyena, when you look at it, is kind of, it's a weird thing, isn't it? you look at hyena and yeah, okay, it's kind of a little bit dog-like. But once you start looking at them, you think, no, that's actually just, that's hyena-like. You know, they are out on their own. So, yeah, but they have a, I mean, when you see a group of them moving through the landscape, right, and they're looking to take something down or whatever, they've got this social structure going on

and they're communicating with each other. There is a very canine aspect to them. But, yeah, they're actually in this feel-of-a-formist group, the group that's more closely related to cats. Yeah, that's something completely new on me. Thank you, first. And so the most iconic thing about it. I mean it is obviously going to be, well, either it's spots or it's laugh. What is, what's the deal with that laugh? It's not just, you know, soulless cackling. No, it's basically as a kind of form of

communication. So they are a social organism. They spend a lot of time in groups and to keep those groups coherent and together, they have lots of communication going on and a lot of that is some of it's visual and, you know, they use pyromodes and so on and sort of smells and urine patches and all sorts of other bits and pieces, but some of it's auditory. And what we sort of associate as to kind of the laugh of the hyena, the cackle of the hyena is that communication. They can use it for all sorts of stuff, excitement, fierce. It's not just sort of, I'm over here.

They can be communicating things about their sort of internal state as well. And it helps to bind those groups together and to coordinate them in a way that allows them to get sort of stuck into some of the things that they do. They'll often produce that noise if they're threatened or under attack. And apparently they can also, which I have. find quite interesting. They can produce it when they're frustrated. It's sort of interesting that you start to, when you start looking at these social mammals and you start reading around about them, you can see all kinds of responses within them that you start to associate with

with sort of slightly more sophisticated creatures than you might think. And, you know, things like fear and frustration and so on can produce these sort of communications. So yeah, much more complex social lives than we might think. And they're certainly very vocal, aren't they? They, they do seem to be talking all the time. Yeah, they can be at times. And, you know, again, that's one of those things with social organisms. You find that a lot. Yeah, interestingly, actually, even if you're looking at sort of things that aren't mammals,

and even if you go down to kind of honeybees and ants, they're always communicating with each other. But they tend to do it with smells, which we can't sort of see. And in fact, we can't even smell them. But those communications are going on all the time. And you look up through social groups, you find communications really central to binding things together. So, yeah, within the hyenas, you're getting exactly that. level of communication going on. And so what do they tend to feed on?

We talked about their sort of hunt, but they've got quite a wide diet, don't they? Yeah, particularly if we're, I mean, if we look across the group, which I think is quite interesting to do, you've got sort of hardwaters concentrating solely on termites, which is not what we associate with them. The striped hyena and the brown hyena will take small prey, certainly if they're given the opportunity, but that's a key word, actually. A hyena are very much opportunistic animals. So they'll chew on a dead giraffe if they find it.

They'll chew on human remains if they find them. There's all sorts of records of that. About 5% of scat that was analysed in study in Ethiopia, for example, had human hair in it. And most of that was thought to have come from digging up human remains, rather than sort of actively predating on us, although we'll come to that shortly, I'm sure. So they are very opportunistic.

But yes, Spottinainaina will take down quite large prey. I mean, they'll chase it down and start ripping at the underside. So, I mean, a classic way that they're going to take down larger animals, like wildebeest and antelope and so on, is to carry it, a very canine way of attacking, actually, the same way that African wild dogs do. They'll go into the softer areas underneath and essentially try and disinvow the animal, which is gruesome, but effective. And once the sort of guts are hanging out and the animals down on the floor, they'll start consuming it before it's dead. And you see that happening with wild dogs as well. there's some quite brutal videos that people have posted on YouTube and various other things of kind of impala falling prey to these sorts of things.

So they're very effective with that with smaller prey. They'll typically go over the head and neck, and that actually includes the way that they would attack us. And then, you know, if they're walking along and see a tortoise, they'll have a go at that. And, you know, they're very opportunistic. But then, of course, they're also attracted towards, I guess what we would call carrion, but, you know, reasonably fresh kills. They'll be in helping to break down those carcasses and splitting it up.

And they've got incredible digestive systems. I mean, they can basically eat pretty much anything without getting ill. They'll eat anthrax-infected animals without having any major population problems, which is a great service they provide. They can clear up these things. They seem to have got a very robust constitution, I think would be one way of putting it, a gut that can pretty much process anything. So, yeah, they're very, very much opportunistic.

But formidable predecessors when they're doing that. We're going to dive into this. but there's also populations of them living, or at least feeding in and around the sort of big, huge kind of landfill scrap heaps in Ethiopia. And is that the same sort of stuff they eat? I'm just sort of think, is it naive to think of them like the foxes there? Yeah, no, I mean, they are the urban foxes of those environments.

Yeah, that's exactly the kind of analog. And you'll get hyenas around these kind of waste heaps. And living actually peripherally around human settlements. And during the period where they can access it, they'll be taking, for example, slaughterhouse waste. They're very partial to. And that's a tremendous service, actually, getting rid of some of this waste. You can see that people have studied their scat during this period. And what happens is that they're often feeding on this slaughterhouse waste.

So you can detect the remains and sort of hair of different animals in there. But during a particular religious festival in Ethiopia, people aren't slaughtering animals and actually what happens then the hyenas switch diet i think they're mostly switched to donkeys so they're taking and preying on domestic livestock and then they start slaughter housing and slaughterhouses start up again and then they switch back so they're very very opportunistic and very able to live and that that's of course a brilliant trait when you want to live around human settlements because we're always changing and offering opportunities for if you're able to take them and you know that that has allowed them to do very

one in some of those areas. And to go back to the show, which is a great lesson, one of the researchers sort of estimated, didn't they, that by clearing up all these kind of anthrax-infested corpses, they were actually potentially saving a number of sort of human and animal lives. Yeah, it's really interesting. I mean, they started to put a financial figure on it because of the sort of the savings as well. And then, yeah, you can put some sort of, I can't remember the exact number, but some sort of number on how many lives were saved. I think it was five across the year of human lives, is considerably more livestock.

And that's been a really interesting theme that's come out of this and some of the other programs and some thinking about it. So I was reading around about cougars, for example, which is one of the species we might cover in a later episode. And it's been really interesting with them because one of the advantages or one of the benefits to us that they have is that they tend to keep deer numbers down. And deer are often a prime cause of road traffic accidents.

both injuries and fatalities. And there's been all kinds of estimates as to how many people's lives have been potentially saved by the unseen presence of cougars in the wilderness around them that have taken out deer that there have been prevented road traffic accidents and stuff. And it's these kind of hidden advantages of predators, I think, that are quite interesting because obviously they also produce problems for us. But, you know, that's with everything, there's a balance.

And I think the idea that hyenas are actually providing a benefit bit in terms of public health and sanitation. That's a really interesting, a really interesting kind of twist on why having predators around is a good thing. And you touched on it earlier, they, they have these reasonably famous sort of bite power, don't they? And that's actually to help them, they actually eat the bones. They don't, they don't leave anything. Yeah, they are, they are formidably powerful, the jewels. They've got massive, these carnassial teeth, the kind of big, sort of buttress teeth all the way down the side and these huge kind of, yeah, They're formidable looking things and that allows them to crush up all the bones and everything else.

And in fact, when you sort of out about, you'll see hyena kind of poo. And it is often very, very chalky white. And that's caused by all the kind of bones and stuff that they're eating. So, yeah, they're pretty for, which, of course, they don't need as much as they take in. So, yeah, they're pretty formidable when it comes down to consuming things. And of course, providing a great service in terms of the environment, because there's lots of animals that can take advantage of a country. carcass if they could just get into it. And, you know, hyenas are able to do that.

So they're these carcass breakers that let everything else sort of have at it, really. It's quite, I mean, it's quite impressive when you see a carcass disappearing down the gullets of various things. They create opportunities for other scavengers to come in. Things like vultures and crows and so on that are able to kind of peck around, but they can't really get into the guts and the marrow, if you like. And, yeah, we put a kudu carcass out that are, you know, got entangled with a fence, I think, but anyway, it was dead.

And we had camera traps around it and stuff, and you see all these kind of animals coming in, and you walk back about 24 hours later. It's like a vertebra and a sort of half a leg bone, and that's about all. And you realize just how formidable these animals are when it comes to just consuming whatever's in front of them, and recycling, you know, it's nutrient cycling when it comes down to it. So they're really, they're really, really vital for the community. So I think Disney possibly did them a bit of a disservice in their kind of role as the evil fight pick. Yeah, I think so.

And it's interesting, isn't it, how much of sort of power does that kind of representation have? And I think it probably has, I think it probably is quite powerful. You know, if your impression of animals is built up from that type of stereotype, then why are you going to care about conserving hyenas when there's majestic lions to conserve and so on? And of course we know that all these things are lumped in together and we need to be looking after all of them. So yeah, so that's a constant struggle within conservation is thinking about how people value certain species and not others and the idea of charisma and everything else.

And yet it's an interesting one. Do you know much about how they're perceived locally? Just think about our particularly Western view of them. Yeah, that's interesting. There's been quite a few different studies about this. And a lot of it comes down to how much livestock predation people suffer. So in actual fact, when predators in general, not just hyenas, are attacking people, that is

obviously a bad thing and hyenas will attack people and there's lots of cases of it happening. But it tends to be much more powerful if they're attacking livestock in people's livelihoods, partly because it has knock-on effects for lots of other people, partly because those sorts of attacks probably happen more frequently as well. So in some areas, hyenas are not particularly tolerated. I think there was one study where sort of 83% or something thereabouts of farmers would basically didn't want resources to be put into their conservation. But there are other areas where they're tolerated. And then some areas where there's almost a sense of veneration and they're linked into kind of a spiritual angle,

partly because they eat because they eat dead things and they will eat corpses, human corpses. There's this sense of, you know, they're a sort of intermediary between different types of world. So there's a spiritual angle to it in some areas as well. Well, of course, because these species live across quite a wide area, you know, spotted hyenas distributed across a lot of sort of southern, eastern and parts of Africa. You've got the striped hyena used to go and still does in some areas, goes up to into Europe. You've got them in sort of parts of Russia and up through Turkey and things. And then across into India. So you've actually got this quite interesting geographical suite where you've got lots and lots of different cultures and lots of different historical relationships.

So our relationship with lots of predators and lots of organisms is complex, but with hyenas, it's particularly complex because of these different behaviours that they do and the fact that they're quite widespread. So, yeah, it's an interesting one, our relationship with these animals. I think I'd be remiss if we had a conversation about hyenas and we didn't talk about their sex differences, which is pretty remarkable. I mean, first off, they are matriarchal and the females are bigger, aren't they, than the males tend to be. Yeah, which is unusual for mammals. And yeah, they're female, they're female-dominated and

female-led societies, yeah, which is, which is one aspect that's slightly unusual. Of course, that's also accentuated by another unusual biological aspect of the females. They're difficult to sex, aren't they? They are. The females have a pseudo-penis, so it's almost as big as the males. I mean, I think, I think like 17 versus 19 centimeters or something, it's essentially from a distance or even close up the same. It's actually their clitoris that's enlarged, so it's erectile, and it looks, you know, it looks like a penis. And it gets more bizarre than that in a way, because behind the penis, there's actually the labia refused to produce a fake scrotum, which I have on good authority and not something I ever intend to test. The only real way to tell the difference between those two is to,

is to palpate the scrotum. If it's a male, you can feel the testis. And if it's a female, apparently, they just feel a bit sort of like a kind of fatty mound. But yeah, I assume my ticket is read that the animal was an euthatized at that point. But yeah, and they have these kind of this sort of this setup. They actually give birth through the clitoris. Painfully fair. Yeah, they signal with it as well, actually. So the females will signal other females and kind of sort of erect it and unerrect it and use it as a kind of, I don't know, like a semaphore flag, I guess.

But yeah, they also give birth through it. which is clearly quite a tricky operation. I spoke to Kay Holkamp about that, and she suggested that, yeah, it seems probably more dangerous to the offspring than to the mother. Some zoo, I think some captive hyenas struggle a bit, but she suggested that's because captive animals are a little bit out of shape compared to their wild counterparts.

But, yeah, it causes physical injury to them. So you can actually see through binoculars, I believe, there's sort of a scar that shows that they've given birth, which can be quite useful for biologists, I guess. But yeah, it's a pretty strange arrangement. And you're right, when you look at it, you kind of assume it. I mean, I did the same thing when I first heard that hyenas have pseudoponies. I just kind of assumed, well, you know, really.

And then you see a photo and you're like, yeah, no, fair enough. That is exactly what it says on the tin. So, yeah, they have this strange biology. And I think, again, you know, we touched on it earlier. It's one of the things that draws zoologists and biologists to them, because they are just a little bit different. That's the spotted eye, you know, that's not the case in all of them. But yeah, they've gone out on a wild card there.

And then so interestingly, which is also, you know, part of what the show focuses on, which is how these, I suppose, in the modern world predators are coming in, you know, ever more often coming in close contact with humans. The spotted hyena in particular, I believe in Ethiopia, is getting, you know, quite close to urban spaces now. Yeah, in part. because, of course, we have urban expansion. You know, it's a form of habitat change.

So we were sort of getting into the landscape more. And, of course, the other thing is that we offer opportunities. In a case of hyenas, we offer things like slaughter waste. We've got waste heaps and sort of things that generally are on the periphery of urban areas. And, yeah, so we're finding more of this kind of urbanization of predators. It's happening in India as well with leopards. Urban leopards are increasing in number. fueled, in fact, according to some people, by the presence of feral dogs, which they have a

particular pawn shop for eating. And, of course, so there's another potential advantage of having leper to run in that they're taking feral dogs out, which can be a source of rabies and other things. But once feral dogs are out and about, then children and smaller adult humans are often on the menu as well. So there's a tension there. So we're finding some, you know, these examples of predators moving into cities or moving into the outskirts of cities. But of course, you know, that comes with some costs as well as benefits.

Yeah. And so in the episode about hyenas, there was one time to some particular we were talking about how it's almost become a tourist attraction in one place. Yeah. I mean, again, people want to see these creatures. We have a fascination for predators. I think I'd take people down to southern Africa quite a bit. all kinds of different reasons and the one thing people want to see pretty much above everything else is a lion. That was Adam Hart there talking about hyenas. If you'd like to hear Adam and I dig a little deeper

into the world of fierce predators and their relationship with a human world, check out instant genius extra. A bonus podcast available via subscription on Apple's podcast app. Alternatively, do check out tooth and claw, which is available on BBC Sounds Now. I also know that Adam's working on his own book about our relationships with dangerous predators called Eater to be out soon. Thank you for listening. The Instant Genius podcast is brought to you by the team behind BBC Science Focus magazine, which you can find on sale now and supermarkets and newsagents as well as on your preferred app store. Alternatively, you can come find us online at ScienceFocus.com. See you next time.

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