Bonobos with cultural preferences

If you were to charter a plane from the capital of the Democratic Republic of Congo, fly for 4 hours, then spend 6 hours on a motorbike, and finally travel for several more miles on foot, you would come across a field site where there’s a unique phenomenon taking place: two groups of bonobos that have distinct cultural preferences. Eva Higginbotham heard what they’re up to from Liran Samuni...

Liran - As humans, we are this crazy special, unique species. We are all over the world. We are capable of cooperative behaviours that have no parallel in the animal kingdom. And one of the things that is considered to be uniquely human is our great capacity for culture and cultural differences, which are group-specific behaviours that are acquired through learning. And I think one of the questions is, where in the history, in the evolution of our species, did we develop the tendency for cultural behaviour or cultural differences, traditions? When we study the evolution of humans, one way is through fossils. We go to excavations and we find fossils that tell us a little bit about the history of our species. But when we want to look at specific behaviours, it's very tricky with fossils because behaviour does not fossilise. And in that sense, we turn to some of our relatives, primates, and especially bonobos and chimpanzees who are our closest living relatives. This paper looks at what we call diversity of behaviours and especially one that is emerging between two groups of bonobos that live in the same environment. Each group is specialised on the hunt of different prey. One group hunts antelopes, small antelope called the Diker, and the other one hunts a gliding rodent. The striking thing is that despite the fact that they live just in the same environment, they hang out in the same places, they still show this group identity in terms of what they feed on

Eva - Is that surprising for animals of the same species that are in the same environment to have that difference in behaviour?

Liran - I think it's very unique and special. Yes, because we can imagine that a lot of how behaviours form and come about is in animals reacting to their environment. If the environment is a certain type of environment, then different behaviours can emerge. But here we have the exact same environment and still almost two different solutions to the same environment.

Eva - Antelope are just such different animals from the smaller rodents that the other group hunts, it seems like such a big difference in strategy. Where do you think that comes from between these two groups?

Liran - That's a great question. And it's a bit of a mystery. One idea that we had is that meat is a high quality food, but it's very rare and it's hard to attain. So hunting frequencies are quite low. And when they're managing to catch the animals, they're super excited, really hugging each other, vocalising, and a lot of excitement. One idea that we have of how this could happen that two groups that live in the same area have such different techniques in a way to avoid competition between them. So if we can imagine that there is this high quality food that is hard to access, and it's very rare, it might be advantageous for each group to specialise on a different prey, so to avoid competition or to reduce the competition.

Eva - What might this tell us about the evolution of culture?

Liran - We know by now that community culture, which is knowledge that is transferred from generation to generation, and the culture is shaped through knowledge that is passed on - I think this is something that we don't have great evidence that nonhuman animals have that. However, the basic capacities of culture, which are two different groups, no differences in their environment, but still showing some diversity of behaviours that is evolved as a function of learning, I think this shows that on the prerequisites of culture as it's seen in humans today. So I think especially the fact that both bonobos and chimpanzees show these abilities tells us a lot about how our ancestors were. Another very important reason why we want to study those animals is in terms of conservation. There is knowledge in the world that is in nature and in wildlife and we can look at it almost as a library full of books that no one has ever read. And through research, we are able to get a glimpse at some of those books. And I think with the biodiversity crisis, it's almost like imagining that this library will be burnt and this knowledge will be forever gone. So I think in some ways, studying those animals, we are trying to preserve some of this knowledge and at the same time conserve these incredible animals