The Infinite Monkey Cage - Monkey Business - Robin Dunbar, Dave Gorman and Jo Setchell

Episode Date: December 17, 2025

In perhaps the monkiest Infinite Monkey Cage episode there’s ever been, Brian Cox and Robin Ince attempt to uncover the secrets of love, lust and friendship in primates. Swinging by to offer a hand (or tail) are evolutionary psychologist Robin Dunbar, anthropologist Jo Setchell, and comedian Dave Gorman.Together the panel explores Dunbar’s number in monkeys – the idea that the number of friendships an individual can maintain correlates with brain size – with the very creator of the theory! They ask whether monkeys feel love the way we do, why some species remain strictly monogamous but others don’t, and what we could learn about ourselves through studying them. Robin goes bananas for bonobo fashion, while Dave couldn’t give a monkey’s about finding an aftershave to complement his natural smell.Series Producer: Mel Brown Researcher: Alex Rodway Executive Producer: Alexandra Feachem A BBC Studios Production

This BBC podcast is supported by ads outside the UK. Hello, Greg Jenner here, host of your dead to me. In my new family-friendly podcast series, Dead Funny History, historical figures come back to life for just about long enough to argue with me, tell us their life stories and sometimes get on my nerves. There's 15 lovely episodes to unwrap, including the life of Ramsey's the Great, Josephine Baker, and the history of football, plus much, much more.

So, this Christmas, give your ears, a treat with Dead Funny History. You can find it in the You're Dead to Me feed on BBC.com or wherever you get your podcasts. Hello, I'm Brian Cox. I'm Robin Ince. And this is the monkey-est infinite monkey cage yet. It's key childhood memory for many to be walking around the zoo and getting to the monkey enclosure. And then seeing that something is going on, you're just a young, innocent child. And you say, Mommy, what's that monkey hanging in that tire doing?

And she goes, look away, Brian. Look away. There's nothing of interest here. But mum, I'm really interested. There's all things going. No, let's go to the chinchilla enclosure. But mother, I'm left with questions and answered that might damage me in the future. I'll only be able to deal with particles, not living things. Psychotherapists actually do believe that it is this experience that Brian and so many of you have had in the zoo that can lead to a rubber fetish. though only if the rubber has a six-inch tread. But today... I love the way that rippled around because people were reading different images in and surprising yourselves.

I think most people are just questioning a six-inch tread. That's enormous. What kind of tire is that? That's a tractor, isn't it? Not six inches. That's two or three inches at most. No, I don't know anything about cars. This is going to be.

make no sense now but anyway but today we're looking beyond the tire or indeed we're going through the tire which was one of Lloyd Grossman's less successful animal-based shows because we're going to look at what we can learn from and I will use more radio four language than my colleague here the romantic behavior of monkeys we will be asking about the monogamy of the mandrel the gregariousness of the gibbon and the temptation of the tamarin. Do monkeys appear to fall in love? How does sibling bonding vary?

What gets a monkey hot under the furry collar and how often do we see them exhibit same-sex behaviour? Ultimately, what do we learn about ourselves by learning about the love life of monkeys? To aid Nabatis, we are joined by a psychologist, an anthropologist and a crucibleist. And they are.

Hello, I'm Robin Dunbar. I'm Professor of Evolutionary Psychology at the University of Oxford. and I spent most of my life studying monkeys and humans and feral goats. And I think the most surprising thing that I've seen really with monkeys is just how Machiavellian and scheming they can actually be. They really are like watching humans. Hello, I'm Joe Setchel.

I'm a professor of anthropology at Durham University. I study mandrels, who are a very very, large, very colourful species of monkey that live in the rainforest of Gabon in Central Africa. And the most peculiar thing that I have learned from studying those monkeys is that they use their vibrant colour to avoid conflict and that they have a scent gland on their chest, which they rub against trees to advertise who they are, how high ranking they are, and even their DNA. My name's Dave Gorman.

I am what I am, and what I am needs no excuses. I've just learnt that a mandrill is a type of monkey and not a euphemism. And the thing I found most edifying from watching monkeys is the knowledge that they are literally too busy singing to put anybody down. And this is our panel. Let's first of all just start off. Joe, in terms of what is the kind of variety of, I suppose, well, romantic relationships that we see in monkeys or sexual?

It's hugely varied. So if we think about primates, all of the primates, it can be from a long-term bond that lasts decades through to a relationship that lasts seconds. The cutest relationship, I think, is the TT monkey. So they're one of the ones that form very, very long. term pairs. And as far as we know, which is not very far, but as far as we know, they're relatively monogamous in those pairs, and they sit in trees and twine their tails around one

another. That's a romantic relationship. They sit together and twine their tails around each other. They're a very cryptic species, which means they hide a lot, so they hide in tangle of vines in the trees, but they always forget their tails. So you walk a lot around in the forest and just see these two tails hanging out of the forest and you know where the TT monkeys are. I think you're sort of you're imposing some sort of cultural paradigm where you say they twine their tails

and that's romantic because you might also say that's jealous and possessive. That's I always know where you are. And also if you're always forget your tail to combine your tail with someone else's tail will improve the likelihood of remembering your tail. Absolutely.

Robin, what about for you in terms of looking at what we might see? Let's say romantic because even defining that can be quite difficult, can't it? We project something of ourselves onto that behaviour. Yeah, it's actually much easier to define friendships in monkeys because their friendships are very similar to our kind of friendships, the way they set them up. I guess romantic relationships, they kind of look the same,

but I mean it does vary enormously from species to species, and even within a species. Well, just like humans, I suppose. different individuals, you know, have different intensities of relationships through introverts and extroverts. From an evolutionary perspective, Joe, so you talked about this whole variety of relationships, polygamy, monogamy, is there anything that's favoured evolutionarily? Can we say, well, it would be better if a species only had monogamous relationships,

long-term relationships, or what would you say, a large number of two-second relationships? They're all favoured evolutionarily. which is why they exist. But the kind of boring ecological answer is that it depends on the distribution of food. And it depends how many females can live in a group. And how many females can live in a group determines how many males can be added to that group.

So if there's enough food for just one animal, then a female has to live on her own. She might, or she'll have her kid with her, but no one else. If anyone else tries to join her, make a group, then there wouldn't be enough food. It does get more complicated than this, but that's the basic.

then if you can have two females living together then they might allow a male to join them there are advantages to having a male join you you avoid harassment from other males you probably do better in terms of protection from predators eating you but at the same time the bigger the group the more likely the predator is to find you

and then if there's plenty of food then you can have a large group of animals and when there's a large group of females no one male can control action to them. It's complete chaos. It is complete chaos, exactly, with a bit of order underneath. Is monogamy more prevalent in a smaller group or in a large group? In a small group. So where you have just one female, she might choose to share her area, we call it home range, with one male. And she might also choose to only reproduce with that one male. But she could also share her

home range with one male and reproduced with other males. Okay. So Robin, you were just mentioning there the chaos. Do you find yourself sometimes, say you're out on a Friday night and you look out the streets and you think, how much am I learning about the monkeys by watching the humans in the same ways I learn about humans from watching the monkeys? Actually, to be fair, a lot of the stuff that we've spent the last 20 years doing is being on humans in order to understand monkeys better. You can do things with humans that you can't do with monkeys. You can stick humans in neuroimaging machines. and stuff like that, and you can ask them questions.

Give me an example of one experiment, you might think, right, if we do that to some humans, that will help us understand this particular group of monkeys more. Okay, so the number of friends you can have is limited basically by the size of your brain. That's a generic relationship across mammals as a whole, basically, but in primates, it takes a very quantitative form. What we were able to do with humans originally

was to look at your purpose, personal social network and tie that to the size of different bits of your brain. So there's a very, very strong relationship. So we don't actually need to ask you how many friends you've got, Robin. We just need to look at your brain and we can tell you. This is one of your most famous and most quoted pieces of research. So tell us, yes, that it is known as Dunbar's number. Dunbar's number, yes, yes.

That's the limit on the number of meaningful relationships you can have, friends and family and that's about 150 in humans that's actually consists of a series of of layers of friendship of greater and greater intimacy as they come in towards you got a small group of very close intimate friendships and then bigger and bigger circles of less intimate friendship so the average is 150 but how you are between 100 and 250 correlates with the size of particularly this part of your brain but also bits around around here That's the frontal cortex. Yeah, it's prefrontal cortex, but also the temporal lobe. And then inside that, there's this massive wiring connection,

and it's the default mode neural network. And they called it the default mode neural network because they had no idea what it did. But when you put people in the scanner, brain scanner, and told them to relax and not do anything, then this network became very, very active. And being, as though a neuroscientist, apologists and neuroscientists in the audience and didn't actually know what was going on inside people's heads. They thought it must be the brain daydreaming

and it's turned out basically when you put in that sort of situation what do you do you think about friends family relationships the social network so the thing is going crazy because it's thinking about the network and then since we did those originally been about

25 studies now showing this in humans new imaging experiments have been done on three groups of monkeys, the same effect being shown at the individual level. So through neuroimaging of like Dave or Brian or Joe or me, would we be able to see how shallow our friendship as well? Yes, exactly. Or even if you have any. How does that scale? So if you go to, I don't know, let's say a macaque or pick a species. Then how does it change? Does it change in a linear fashion? If it's twice this. So you'll like this little bit because it's math.

Then, by the way, if you want any evidence of how actually functional that is, that it really exists as number, somebody did an analysis of 61 million Facebook pages, counting all the friends on each of these 61 million Facebook pages. The average was 149. They've made the great mistake there of assuming that the people I'm Facebook friends with are people I'm friends with. in general they are your 150 friends as I mentioned earlier are divided up into a series of layers those layers have very very specific numbers they're 5, 15, 50 and 150 so the 5 is what we call your shoulders to cry on friends

they're the ones that will when your world falls apart they will drop everything and come pick you up again turns out that those numbers are optimal for the efficiency with which information flows through networks and what's more those are the numbers you find

not only between species of primates but also within primate groups the structure of primate groups has exactly those numbers as well so they don't run to the 150 because they don't have as big a brain as us but for those species

like baboons and macaques and chimpanzees that live in groups of 40 or 50 individuals they're substructured in exactly the same way as human social networks are. What are the other forms of behaviour that we might expect to be different depending on the cognitive ability

to have that many kind of social connections? You've got what I call the line dancing problem. Imagine you're in a group, you're foraging through the grasslands or the woodlands of the savannah or the forest or whatever it is. How many people can you have in a group and still have the people at either end in time on a line dance.

The answer is, without music, very small. And that's the, this problem, it's the synchrony problem of moving in the same direction. It's really hard work for monkeys and apes and the few other species of mammals that have stable groups to try and keep the group together. And initially they do it just by sort of keeping track of their neighbour and keeping going. and will only really allow you to work with up to a group of about 15 maybe maximum and that will be about five females

and maybe three males, something of that sort of size and the rest are kids and you have to break through what's a glass ceiling at that point and produce something else. The producing something else is to do with grooming bonds so they can, at that point they start to invest very heavily in social grooming to create this really,

intense friendships, bonded relationships that keep individuals together. So your friends will keep checking on you as well as you keep checking on them. And that will do up to about 30, groups of 30. And 30, there seems to be another glass ceiling and you have to go through that. And that's when they start to use serious cognition. The brain really starts to produce major new kinds of cognitive strategies which allow them to figure out who's doing what with who, basically.

I think I've just realised why S Club 7 split up. Because each of them realised that only five of the others would pick them up when they were down and resented the other two. Although I am assuming they were all capable of serious cognition.

So maybe that's not right. How much does that affect, say, the Osmond's? Because they're also, you've got an actual genetic link as well, which will probably change the relationship, wouldn't it? Well, how much does it affect all family bonds if only five people are allowed in that inner circle.

The minute you've got a six-person family someone's in trouble. The way we've talked about it so far is quite mathematical it seemed to me. But when we talk about, of course, even in relationships there's a large amount of choice involved. So I suppose

I'm asking questions like, is there a pin-up monkey, is there a handsome monkey that everyone would go for it? Why are you bringing up, is there a pin-up handsome monkey, Brian? What are you? I just wonder if there's any self-interest here that we're watching. It's because it's written down here on the script. You wrote the question.

You wrote that. I remember you doing that, crossing out the other. One is there a monkey that wears a card? And you went, oh, I don't want to do that. So when I started studying mandrels, I was attracted to them because they have, they're very colourful. And I wanted to know whether there's a pin-up effect. So whether the most colourful animal is the most impressive,

but perhaps, perhaps attractive to females and so on. And I've been studying them now for decades. And initially, I did discover that the pin-up animal, the most colourful animal, has the highest testosterone, is the highest ranking. And I thought, oh, yeah, so I'm really figuring out something here. He's probably the most important. And females do like to hang around the most colourful animal.

But there are many other things that come into it too. So there is his colour. There's also how nice he is. if a male is brightly coloured but horrible, females are just not interested. And it turned out much later, when I alluded to their genetics, what they're really interested in is genes, and it's got nothing to do with the colour. So it's the males that are colourful?

Males and females. So males are incredibly colourful, so we focus on that. But if you didn't look at a male mandrel and you just saw a female mandrel, you'd notice that she was very pretty and very pink coloured. So pink nose, blue facial stripes, very precious. And is it the females that are primarily making the choices? It's both. So yes, females definitely choose.

Females have the advantage of being much smaller than males, which means that they can get around a lot more easily. I've seen males mate guarding a tree, thinking that their female is up the tree, when the female has jumped out of the tree about 10 minutes ago and has run down, jumped into another tree, run down, run out of sight, and turns up later with another male. the through line we see is that the male remains the idiot

I'm a female primatologist so yeah that's the conclusion and remembers to lift the tail up so it's not dangling down to give away where it is so that's so mandrels don't have that problem because their tail is only a few inches long and you mentioned genetics so in terms of the traits that will be attractive beyond the colour what are the traits that the females are looking for immune genes so the strength of the immune system but not actually that how do they gauge that through

smell so there's a link between the immunity genes and the smell of the animal and they're not they're partly looking just for a good immune system but they're really looking for a match between their immune system and the males immune system actually this works both ways males also base their mating decisions on the female's genetic makeup and in the end the point is to make a better quality immune system in the baby. Has that changed in terms of the understanding of humans though? Because remember when we had Matthew Cobb on a while ago and he was saying that actually the olfactory senses in humans

during kind of dating mating is not quite what we thought it was before. Ah, so I think it's changed our understanding of humans in that we're not consciously aware of odour but we're very unconsciously aware of odour. So it affects us enormously, it brings back memories to us instantly, but we don't necessarily think that we're influenced by it. So perhaps what we know now about primates and other mammals has influenced what we know about humans?

But we're the ones who shower and put scent on and do stuff. So we're messing with a system to try and game it when actually, if we left alone, we'd probably mate more successfully with people who were better fit for our immune systems. Not entirely because your choice of, well, I don't say your choice of perfume, but in general, women's choice of perfume, but I guess that applies to aftershaves in the case of men, is directly correlated with your natural smell from your immune system.

So you like the perfumes which actually enhance your natural odour. This is why, if I may give you some belated advice, Dave, don't buy perfume you're saying he's too late for him now because you'll buy something you like not the one she likes okay well thank you for giving me a retrospective excuse

I'm never buying perfume for my wife I've got to be honest with you Dave I remember when you gave her a box set of Lynx Africa she looked overly happy are you improving your chances When you choose your perfume and you're saying this will be kind of matching with the smell. Is that improving the chance? In a way, possibly.

But there are other ways in which we also can pick up on our genes. So one is in the odour that we have on our body. Another is in the mouth when we kiss, for example. So you might wear some fabulous perfume that is created to attract the opposite sex, but it won't take you as far as kissing. Well, obviously I didn't kiss my wife until she was my wife and it was a bit like that. I remember that moment, you opening your mouth going,

about to have fresh breath, links Africa. This leads us on neatly to the next question. It doesn't, though. Because as we've just discussed, sexual behaviour in humans is extremely complex. Do we see such complexity in the sexual behaviour? We see lots of different sexual behaviour. So definitely, yes, both across species and within species.

And also simply diversity of partner choice. So we have sexual behaviour between males and females, between males and males, between females and females. In some species, like Bonob was famous for involving all the different age classes too, which we don't do as humans, or at least legally we don't do as humans. But is that right about, because I know we're mainly talking about monkeys, but if we move on to apes as well, I remember. being told a thing about the fact that bonobos would also have kind of a fashion sense, that they would sometimes pick up, like, say, a dead rat and wear it on their head

and kind of parade around. And that's your idea of fashion. A paris. It fits, doesn't it? It does, yeah, yeah. So things like that, a kind of flamboyant display, which includes accessorizing. I suspect that monkeys don't need that sort of accessory in the way that bonobos might, I don't know, because they have their own accessories.

They have bright red noses and blue stripes on their cheeks and colourful genitalia. Maybe they don't need a rat on their head. It's fascinating, so it's like they're describing the difference between the mating technique of Adamant and Rod Stewart.

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HelloFresh.C. Hello Fresh, Canada's number one meal kit delivery service. Hello, Greg Jenner here, host of Your Dead to Me. In my new family-friendly podcast series, Dead Funny History, historical figures come back to life but just about long enough to argue with me, tell us their life stories, and sometimes get on my nerves. There's 15 lovely episodes to unwrap, including the life of Ramsey's the Great,

Josephine Baker, and the history of football, plus much, much more. So this Christmas, give your ears, a treat with Dead Funny History. You can find it in the You're Dead to Me, feed on BBC.com or wherever you get your podcasts. The behaviours we've been talking about, so complex behaviours, but many of them driven by environmental factors and so on. How much can we read into the intelligence of the individual from the social structures and sexual behaviours that we see?

Depends what you mean by intelligence. That sort of everyday physical world type cognition, everybody has to do in order to live in the real world you've got to be able to compute how far is it from here to where Dave is sitting over there in terms of when I leap of this branch to that branch

to land in the right place and not to land on the floor I love it when a bit of jeopard is thrown into the show but social intelligence that's sort of separate it exploits a lot of the same machinery if you like so causal reasoning and stuff

But the key to that seems to be that it involves what's become known as mentalising. It's the capacity to understand what's going on in somebody else's mind, essentially, or at least to be able to predict how they're going to behave in future, and to manage and manipulate that to some extent. And that is extremely expensive in terms of neural processing time. And that's why you end up having to have this huge bit of the brain dedicated, essentially dedicated to managing social relationships. So if you have a bright red nose, you don't need any of that

because you can just look at someone else's nose and say, oh, okay, I know what's going on. A bit of a sniff to figure out, you know, all the... And that's the difference between herding species, like feral goats, who don't have stable relationships and don't have stable groups because there's no point in learning the ins and outs and foibles of a particular individual because you may never see them again.

All you need to know is, are they a bigger thug than you, are they prettier than you, they've got a nice red nose or whatever the cues are. If you're in a stable group, you've got to do much more machinating, really, in order to keep everybody in the same place. Because the problem is, you know, as I'm sure you all know, if you're too grumpy with your friends when you go out,

you know, they'll abandon you. You know, so if you start sort of being too aggressive within the group, you destroy the group. It's the skills of diplomacy. So, Joe, does it, monogamy, would that, when we see monkeys that are able to commit to monogamy, will we, again, will we presume that this shows various other forms of intelligence? And indeed, even possibly in terms of the rearing of the babies. So there's a lot of coordination involved, yeah, definitely. So if you're living just as two

and you either spend all your time together which can be involved with coordination and giving up what you wanted to do to coordinate with your pair partner or there are some species lemurs actually rather than monkeys where they coordinate within a home range but they're not together they just keep in touch

by yelling at each other vocalising. And the ones that have stable groups, stable monogamous groups as a pair invariably have bigger brains than the ones that have a pair-mating arrangement, but live together. So long-term monogamous relationships, and he said there's an increased brain size associated with that. Does that imply that concepts, a very human concept, like love, for example, which you would associate with monogamy?

Are we allowed, is it appropriate, to begin to think in those terms, which are very anthropomorphic, I suppose, terms? I mean, the answer is yes, if you look at it, it looks very much like what humans do. But I think there is an argument for saying, actually, you know, the best way to study any system, be it of cosmology or physics or humans or animals, is actually to immerse yourself in it so much that you actually understand it intimately from the inside yourself. Then you have a much better sense of how the thing works. and that in some ways the argument that we should be back off from anthropomorphism wasn't a great idea because it divorced you from what the animals are actually doing. The trouble is it's just so hot inside that bonobo costume.

Oh, I know. Let alone how cramp it is if you want to be in a t-tie monkey costume. I would completely agree that we need to immerse ourselves into the lives of primates. It's not typical primatology. There are some people who do it. and it's very useful, then you have the opportunity to describe things like when partner lost, for example, say if a member of one of those long-term pairs dies, you see in the other what is very obvious to us that we assume is grief. From a more natural science perspective, it's difficult to know how you measure that.

But one thing we do measure is oxytocin, and in those long-term pair bonds, oxytocin is called a bond. hormone sometimes. We see that oxytocin is important in maintaining those bonds. It's also important in bonds, even in species that don't have one-to-one bonds. So if you call oxytocin a love hormone, which some people do, then we can try to get hold of the idea of love. But also, I think there's always a really interesting contrast between what people present in academic conferences and what they talk about in the coffee break. And in the coffee break, yes, they'll be talking about how their monkeys love each other, because it's so obvious that they do. Last time I visited a facility, one of my friends works with captive American monkeys,

these little calatricids, and showed me around, and I met all these pairs, male and female, male and female, male and female, and then finally we got to this cage, and she said, oh yeah, this is the two boys. They clearly chose each other, and they're hanging out, and they have these brilliant enclosures, where they all live in jeans, that they're love to live in genes. There's genes hanging up in the enclosures. And out of the two legs of this gene, these jeans popped out these two little male

monkeys and they've lived together. They just chose to live together. They haven't got babies but she reckons that they would adopt if they were given the opportunity. Oh, that is, if Levi 501s don't relaunch with that as opposed but I think at the end

of the day one has to be a little, I mean, anthropomorphism is a two-edged sword, is the risk because you can go over completely on it. So we have to if you're going to study these things you have to be able to live in this sort of dual world as it were where you can exploit

this kind of intuitive understanding that we have of how organisms relate to each other but at the same time step back and kind of look at it more hard nose and sharp and sharp in the end has to come down to, I don't think we'll ever get at it studying it with behaviour, maybe

I don't know, but my guess is we'll only really know if we can pick it up in the same bits of the brain firing up and the same surges of hormones in the system in the brain things like oxytocin and endorphins and stuff and the way those flood the brain during the course of interactions

and they are the same I mean the endorphin system and the oxytocin system are the same in monkeys and humans so you're saying a new a new technique a new frontier of knowledge would be to really to look at the brain of a monkey, let's say, and see the, so we want to see how the neurons fire, if the patterns are the same,

the regions of the brain that are stimulated that the same as a human, that would be the final, the proof is strong evidence that they're thinking in the same way and experiencing the same feelings. I think it's closing the gap, but I don't think you'll ever get to that final point where you know what's going on. I use the word feelings there, so that's the point, isn't it, the root of it?

Yeah. Because, I mean, bear in mind, at the end of the day, we have this problem with ourselves. In other words, we tend to see the world as being populated by people like me. And I understand, because that's the only reference point I have, is how I think and feel inside me. And we kind of generalise that onto other people and assume they're operating in the same way. But Joe, you said you don't think we'd ever get some. to that point where we'd say that the map is now so obvious. Let's say you had a family group and you see exactly how the brains are operating,

then the patterns in the brain are happening. I just think we're still, we might be happy with an explanation until we developed some new method and you could go further and trying to explain what's happening in the brain or what's happening in the endocrine system or anything else that you might be interested in. And you'd suddenly realize that you had an approximation of an answer, but there's still more to do and further to come. go. Even when I say

we might be closing the gap, I think the gap is just there. And it is that the fact that we have to eventually say, well, the patterns are the same. So we are assuming that the experience is the same. But we'll never know if the experience is the same.

I think we've done a very English thing with this show, which is we've somehow really dragged out the bit that has allowed us to avoid talking about sex. In a desperate bid that we won't get to it. But we promised this show would include monkey sex and so please welcome anita and boat no so so to get now to to to that to the actual sexual behavior the nitty gritties the so the first thing is do we do we get a sense uh joe that monkeys enjoy

sex that this this is fun yeah definitely um so if we talk about females i'm female many female primates clearly show signs of orgasm. So, again, if we assume that orgasm is fun, because for individuals it seems to be fun, then, yeah, they're having fun. They also seek out sex. Both males and females seek out sex, not all the time, and it varies between the individuals, but they seek it out, which suggests that it's fun. So there's not, say, a patent in terms of, say, the menstrual cycle of the monkey,

or that they would be, it's not merely, oh, hang on a minute, I can have a baby now that you actually see it as in the same way with humans that people go you know what it's enough fun to not worry too much about the outcome. Loads of reasons for having sex. So yes of course sex in order to

reproduce but loads of other reasons too you started with a story about a monkey in a tyre at the zoo by itself which suggests that it is fun. Is that the tyre element of it? The solo element of it suggest that that must be fun. It can't be doing it because it thinks it's going to lead to a baby,

so it must be enjoying itself. Yeah. So evolutionarily, perhaps there obviously is a link to reproduction, but there's a link to many other things too. In some case, social bonds, between males and females, between males and females and so on. But yeah, definitely. I think as far as we know, it's fun. And in terms of things like, you know, sometimes you'll see these kind of evangelical preachers, tell evangelists or whatever going on about the fact that we, you know, we don't see homosexuality in any other animal, which means they've never even known a dog, to be honest, because...

So again, in terms of same-sex relations, sexual relations in the monkey world. So, first of all, there are plenty of same-sex relationships in the monkey world. I suppose also we should say that when we come to talking about same-sex relationships in humans, whether or not animals do that is completely irrelevant. But if we want to look and determine,

and whether animals do it, primates do it. Yes, lots. It varies across the species, but yeah, a lot. But I think that's in some ways why it's good to know is you go, this is not, you know, people will describe certain things as being against nature when in fact you go, let us look at the natural world and we see.

It's everywhere in the natural world, absolutely, yeah. Dave, I suppose the big question for you really is, and we need a definition, what is love? It's committing to not kissing your wife until you're married, I don't who knows who knows what love is because and even in our own lives most of us believe we're in love and later can reassess that and go that wasn't it actually because until you've experienced it you know so teenagers fall in love but it's not it's a kind of infatuation and later in life when you feel more deeply in love you are able to look back on that and go I just really liked it. it's not the same is it and what I was feeling was an excitement for novelty but it's how do you possibly define

what it is until it's too late what you've described there eloquently is how complex these ideas are but just we are getting quite close to them but Joe in terms of what is love when you're looking at monkeys how would you go

this appears to be what I will define for this piece of research as a loving relationship. Oh, well, I would never get away with calling it a loving relationship in a scientific article, I don't think. Maybe people will in future, but when you write the popular book, that's different.

Right. And is that available yet? I kind of a feeling that humans have somehow gamed the system because in almost all other creatures it's the males who are the flamboyantly coloured, you know, sort of the peacock tail or whatever.

And in humans, it is is the men who grow the beards and do whatever, but most of us shave them off, have a haircut and say, put some makeup on love. And we've somehow gamed the system and gone, make yourself pretty. You put the colour on, we're not doing it anymore. Which feels weird and against...

Historically time-bound phenomenon. There are instances of cultures around the world where men wear makeup and perform for the women to choose. Yeah, which feels like the way it should be, but thank God we've got away from that. Too lazy for that We have just about run out of time Just to give you some insight into the scripts

I'm looking through and is there any question we haven't asked There is one question we haven't asked It's right at the end In this very sophisticated discussion we've had If you could be any species of monkey What would it be? That is the question that's written here So I feel duty bound to ask it

Which species of monkey would you be Eminent professors? Let's go Robin, Joe, David Robin that's really difficult for males anyway because they usually end up in fights which they lose very badly You can be a goat if you want

Well they're as bad Actually I spent a lot of time working on A very small miniature antelope called a Clipspringer Which is intensely pairbonders The most pair bonded Loyally pair bonded species Anywhere in the world I think It's such a relaxed, cosy life

That they have If you see one of them the other member of the pair will be within three or four meters always they're never separated because that's an antelope right I'm giving up on monkeys monkeys are too violent

Joe which monkey I would be a dominant female mandrel for two reasons one is I think they have the best life they're totally in charge they know they're going to be in charge for the whole of their lives and no one gives them any trouble that's the first reason.

And the other reason is then I'd know what it was like to be a female mandrel. So, David? Well, I think the, was it Cliff Springer? Clipspringer. Clipspringer. That does sound appealing, but I am scared of heights. So I'll go for being a female mandrel as well.

Because who am I to argue with an expert? I'm the dominant one. You can be the next one down in the hierarchy. Yeah, there's only one. There's only one. Well, we'll be in separate groups. It'll be okay. So, we also asked our audience a question,

and we said, what is the most curious thing you've seen at the zoo? This one's very nice, isn't it? An inquisitive child. Oh, I have one says, a small monkey stole a tea bag out of a lady's handbag at London Zoo. Which just goes to show,

those PG-tips adverts were very, very... When they did those PG-tips advert, You know the old, if you'll play it or whatever, and it was chimps dressed in human clothes and things. The way they did that, they put peanut butter on the gums of the monkeys so that they would move their lips, and then they had actors lip-sink it.

It's a technology they now use in holly oaks. This is, uh... My wife, she was a keeper. This one, this is like a keeper. This one, this is like a keeper. Complaint, a letter of complaint. Like one of the ones we get from Radio 4 listeners. It goes on for a long time

and it's in green ink. I watch an obnoxious couple get too close to an enclosure, knowing numerous signs of warning about the hippo's curious habit of smashing their tails to spread their extrament widely. I enjoyed watching them sprayed by flinging poo.

For them, flings could only get better. I've just got a Brian Coxillottle. I've heard that rumour. Thank you to our panel. Joe Sechle, Robin Dunbar and Dave Gorman. Next week, it's Christmas.

And thanks to Brian's air miles, we're going to the North Pole to meet Father Christmas and his reindeer. So we're going to ask how exactly do reindeer evolve to fly? And what are the health ramifications of eating two billion minutes? pies and drinking a billion glasses of sherry in one night? Or how do living things survive in polar regions?

It'll be one or the other. It'll be one or the other. Flying reindeer, living things in polar regions. Thank you. Bye-bye. Bye-bye. In the Gepernar and honging cage. Do you're on that nice again?

Hi, it's India here. I'm very excited to bring you the return of child. So we've been on the journey of an embryo all the way to a baby's first birthday and now we are going to enter the explosive life of the toddler because this is the perfect place to unpick the very complicated world of emotions, the emotions that affect us all. So come with us as over eight episodes

we fall through the abundant and dizzying world of happiness, descend into the depths of fear and the gendered and dangerous world of anger and then crawl, wobble and bounce our way through awe, love, anxiety and surprise. From BBC Radio 4, this is Child, with me, India Ackerson. Listen first on BBC Sounds. Hello, Greg Jenner here, host of Your Dead to Me. In my new family-friendly podcast series, Dead Funny History,

historical figures come back to life but just about long enough to argue with me, tell us their life stories and sometimes get on my nerves. There's 15 lovely episodes to unwrap, including the life of Ramsey's the Great, Josephine Baker, and The History of Football, plus much, much more. So this Christmas, give your ears a treat with dead funny history. You can find it in the You're Dead to Me feed on BBC.com

or wherever you get your podcasts.