The Naked Primate

31 March 2022

Cat Hobaiter is a primatologist. A very well-known primatologist, but in her own words she is ‘an ethologist, primates I kind of fell into a little bit by accident’. Originally, she was supposed to be a physicist but got distracted by the evolution of human behavior and changed direction, wanting to concentrate on ‘cetaceans and all sorts of other kinds of cool animal behavioural work’. That was until a cup of tea with Professor Richard Byrne kicked off a career in primatology.

Cat loves being outdoors, and the intricate problem solving of science, so field work for her is the perfect combination. ‘I'm absolutely the luckiest, and a part of that luck is working for the University of St Andrews who are incredibly flexible and supportive’. She still spends six months a year in the field and nobody she knows in her profession gets to do that. This is partly to do with the technology that is now available. Cat can still teach from the middle of the field site on topics such as the evolutionary origins of language.

Big picture stuff

So, what is the basis of Cat’s research – what are the questions she wants to answer? ‘Bigger picture stuff’ is her response thinking beyond the evolution of cognition. ‘What makes us tick as humans? Is that different from how other animal minds work?’ She says different and not better for good reason. ‘I spend an awful lot of time with students trying to persuade them that we are not the pinnacle of some kind of complicated evolutionary process that has resulted in man the toolmaker and that we’re not more or less evolved than a cockroach’. ’Cockroaches are much better at being cockroaches than we would be, all species are very well adapted to the puzzles they need to solve and so there are lots of things other species are much better at. We can't communicate underwater, we can't fly anywhere, we can’t remember the location of a 1000 different fruit trees in a forest, there are lots of things that as humans we’re a bit pants at’.

‘I have lived about 15 years of my life in a rainforest, and I still make a mediocre chimpanzee’. As she continues ‘I’m not bad at being a chimpanzee, I'm probably better than your average human by quite a long way, but I do still make too much noise when I go hunting with them and I do get the look of shame from them. It's mortifying. Everyone is walking silently in a single file row and I'm right there with them. Then I’ll break a little branch underfoot and every chimpanzee will turn and look at you and it’s that ‘we’re not mad we’re just disappointed’ feeling of such shame, even the kids are better at it than me.’ ‘ I think we spend a lot of time thinking about what makes us exceptional and while it is interesting to know if other animals do what we do. I also want to know if we can do what they do - it’s not all about us in the middle of the picture – what is exceptional about being a chimp, or gorilla, or a crow? How does that shape the way they communicate and the way they think’.

Infant chimpanzee looking at camera

Cat has spent so much time with the chimpanzees, they have become family to her. But you don't get to choose your family, right? She gets exasperated with them at times, just as you would do with any family member. Chimpanzees, particularly the Budongo population she studies, have regular infanticide. Just this past summer the Sonso community, who have been plagued by internal struggles between the males for rank position, decided to put that aside (which was nice) and start killing the neighbours (which was not). A lot of this is very hard for her to stand by and watch. It drove her potty – chimpanzees are an endangered species. As she says she wanted to yell stop killing each other! ‘We're trying our hardest to conserve you, and you obviously not doing your part to make sure that the next generation make it through!’.

New collaborators, countries and apes

Studying apes and ape minds in the wild is the crux of her work. But looking at a couple of species in a couple of locations doesn’t work for Cat. That would be ‘a little bit like if we'd studied human behavior by only going to Manchester and Tokyo and deciding that that was the sum total of humanity. Well, that's not very interesting, or it is very interesting, but in highly specific way’. Thankfully she has just secured a big ERC project grant that will allow them to investigate multiple groups of every subspecies of ape in Africa in the wild. ‘We are just starting to scratch at the surface of the incredible flexibility, richness, and diversity that is present in other species’ behaviour. It's been so exciting. Pre-pandemic we got to bounce in and out of lots of new countries and meet lots of new collaborators and the apes they work with. I know each ape group is different; bigger, smaller, different personalities, but I thought after 15 years I could walk into a new group and expected to see familiar social structures and behaviour, but often even those foundational features of chimpanzee life were clearly different from day one. I could feel preconceptions I didn’t even know I had being torn apart. And I love that experience’.


Most of what Cat works on is non-vocal gestural communication. Gesture is a really powerful system if we're interested in exploring the evolutionary foundations of language and human communication. There is a lot of information in other signals too – for example: vocalisations, but often these signals are not aimed at anyone in particular, they broadcast to the world in general, given even if there’s no one there at all to hear them. We give those too – yelling when we stub a toe. What is different about gesture, is that it’s much more about a one-on- one, back-and-forth exchange, which starts to look more like what humans do with language. Gesture is an exchange of signals with a specific partner – with someone else who you recognise has their own reactions and ideas. This type of communication was the gold standard of what made language different, and it was almost impossible to show in other species. That was until researchers started looking at gestures in nonhuman apes. Then the evidence was abundant. All gestures seemed to be used this way. It’s not just one or two signals. There are probably 80 or 90 distinct gestures in the ape system, and they’re exchanged in that back and forth - intentional - communication that is characteristic of human language. Once you have described the basic repertoire – the vocabulary – of gestures, you can look at how they're structured and combined, and this is what Cat does.

Younger chimpanzee touching chin of older chimpanzee

There have been different methods to tackling these questions, but she does it purely observationally. ‘If you spend a lot of time in the field you really get to know how little we actually know about the apes’ world, and it makes me very cautious about tinkering in the system with more hands-on methods’. ‘The potential to influence their social relationships, relationships that have real consequences for their wellbeing as well as their survival, is something I won’t do. So, I'm on the very cautious end of the spectrum when it comes to field experiments, for example. At the same time even as an ‘observational only’ scientist Cat has to face up to the fact that her presence alone has an effect – we found that habituation, the process of getting apes used to us just being present, can shape their behaviour for decades into the future. At the same time, we know that our presence as researchers provides a really strong conservation protection. At the end of the day, it’s about making sure that you’ve thought things through as best you can.

The pandemic

How hard has it been for Cat and her research during the pandemic? Surprisingly she has been able to carry on – with the pros outweighing the cons: ‘We had a lot of long discussions about the appropriateness of doing research because of the risks of the pandemic. We tried winding down one of our sites a little bit, but we had so much poaching of the chimpanzees and cutting down of the trees that we just realized that, whilst trying to protect them from Covid, we were exposing them to so many other risks that it was not worth it. So, we carried on. At other sites we stopped completely. It was a case-by-case decision – but with the principle that people, and apes come first. Doing the science was not our priority’.

For those of you on Twitter, and especially those of you that follow Cat’s profile – The Naked Primate – you will know just how quiet she was during the pandemic and numerous lockdowns. This was deliberate. After taking the decision to carry on research at certain field sites she felt unable to broadcast this. ‘While I love sharing the science we do, I think doing so without context wouldn’t have been responsible – I was always happy to chat to people about why we’d make a choice to go here but not there. But until very recently most of our scientific work stopped, very rightly, and I didn’t want to share things that might encourage people into thinking that it was business as usual. I know the pressure we’re all under at times when grant deadlines are looming but the people we work with and the places we work in have to come first. No questions asked.’

Working in the rainforest

So, what does Cat actually do all day when she’s at the field sites? How does she actually carry out her research? Does she really just watch them interact and play and forage? Yes, just always with a video camera in hand. It’s a big systematic study. To do research into gestures you absolutely have to film but filming in a rainforest is one heck of a task, it is dark, the animals are dark, the light conditions are terrible, and it rains most at the time so subtleties of gestures can be missed in real time.

As so much of the subtlety of ape gesture can be missed when filming, the videos are worked through, often in slow motion, to see all the nuances of gesture(s). Reviewing videos also allows us to really look at behaviour we might not otherwise notice – again it’s about trying to make sure we see the world as the apes we study see it. Sometimes it’s only after months or years that we start to notice a particular pattern and a new gesture or behaviour clicks into place. With video we can go back over interactions and re-examine them as we learn more.


All the time that Cat is following and filming the chimpanzees she is trying not to interfere, but that is an impossible situation. As with all observational scientists, by simply being there her presence has an effect, it shapes the lives of those they are following and observing. The new field of ethno-primatology investigates this porous boundary between human and other primates’ behaviour and how humans, as well as other primates, are shaped by those interactions.

By Cat’s own admission the group of chimpanzees that they have studied for 30 years – Sonso – is quite a small group, with particularly few males, and realistically there is a good chance they would not have survived, except for the researchers that are with them every day. The neighbouring groups are much bigger and stronger. But they are afraid of humans. Whenever there is a conflict (for example, over territory), Sonso wins. Cat and her colleagues are the Sonso chimpanzees’ secret weapon, despite not trying to interfere, their presence does have some profound impacts on the chimpanzees they study.

Open access data

All this filming generates an enormous amount of work to be analysed – all the videos have to be coded. To capture the nuance in this rich system of communication, her lab group codes over 50 variables on every gesture. With such a detailed system, any one data point doesn't tell you very much. But with tens of thousands of cases of gesture, the researchers can start to explore patterns in these huge datasets. One thing Cat is determined to do is to ensure that the incredible resource that is being built up is made available to all. She is fully aware that she cannot possibly make full use of it, and may not be able to analyse it in a way someone else could or would: ‘it's like a data ark, these are endangered species and who knows where we or they’ll be in decades to come? This data is here. Let's make sure everyone can access it.’

Shared gestures

For someone as new to the subject area as I am, I was curious as to whether there was much cross over in gestures between different species – are there gestures that are the same for different species? Unsurprisingly the answer is yes. The closer you are as an ape species the more gestures are shared. Chimpanzees and bonobos are very closely related and share about 95% of their gestures. Chimpanzees, bonobos, and gorillas about 80%, chimpanzees, bonobos, gorillas, and orangutans, about 70%, and so on.

The amount that is shared follows roughly with how closely related you are. It strongly suggests its evolutionarily shaped, and that the gesture types themselves are genetically inherited. Chimpanzees and bonobos are our closest relatives, and we are closer relatives to them than a gorilla would be. So, if a chimpanzee and gorilla share 80% of their gestures, then chimpanzee and a human should share even more. But what happened to those gestures?

A clue can be seen in new datasets that suggest young children (one or two years old) who don’t yet have language, are using a lot of these ape gestures to communicate. Human’s ability to gestural information with chimpanzees can also be evidenced in a small study Cat and Dr Kirsty Graham (Research Fellow at the University of St Andrews) ran with members of the public - a citizen science experiment. They asked members of the public if they could understand the gestures made by other apes in a set of videos, and they could!

It suggests that we instinctively, at some level, still have access to understanding what these gestures mean. We might not be using it very much every day, but we still seem to have access to it. This in itself is an indication that language hasn't fully replaced gesture but has been integrated into this system that our ancestors and our modern ape cousins still use.

Other species

As mentioned earlier, building on the large-scale comparisons from her ECR grant, Cat intends to start observing elephants and also some corvids, essentially asking is this language-like use of gesture an ape thing, or is this a trait shared by all long lived, highly social, highly intelligent species? Cat would love to be able to observe and research cetaceans but at the moment the logistics of getting gestural data underwater feels a step too far, it would it be too much of a technical challenge.  For the moment though, she is continuing her work with the chimpanzees and loving new interactions with new groups and species – especially the Mountain Gorillas. ‘They're so relaxed about everything. They sleep a lot of the day. They eat a lot of the day. They play with each other quite a lot. They are so relaxed with our presence, often if they see me sat there filming, the mothers will come along, drop their baby off and then go off – it can feel like I’m their creche! Because they're so much bigger than we are we’re no threat to them, it just makes them so relaxed about everything’.

Knowledge sharing

Cat isn’t doing this work for immediate results, she hopes to build data sets and scientific resources for the long term, so as many people as possible can get access. Her team is always also mindful that they are working with some of the world’s most endangered species and there is a responsibility to make sure their work contributes to their protection. Cat works with students and researchers from the African countries in which she collects data, to build support and capacity for primate science in the future to be led by researchers from the countries in which these primates live.  She is also working with the University of St Andrews Sub-Saharan African working group to explore how we can build more equitable connections with research partners in Africa.

Chimpanzee chin on handsAs well as the researchers and academics from Uganda and other countries with great apes, Cat wants to make sure her research is useful to other communities. People who live just a few miles outside of some of the forests in Uganda have never seen chimpanzees, or if they have, it’s only been when they come down to raid crops. She began a program of knowledge exchange called Without Words where Cat talks to people about chimpanzee gestures, and how we already understand and recognise many of them because we share a lot in common. It can really help too, to create discussions that focus on what we all have in common - including conversations about why the chimpanzees are coming to take human food. The shifting climate over recent years is having a real impact on what were previously reliable crops and food sources, and highlighting this as another point of common ground between local communities and the wildlife around them helps communities understand the chimpanzees and be more tolerant of them. Everyone Cat has spoken to is really engaged. It's all about sharing knowledge.

Dr Cat Hobaiter

Wild Minds Lab

The Great Ape Dictionary


The Naked Primate on Twitter