Observing apes to get a better understanding of humans

Where do humans come from and what makes them unique? These are the questions that Thibaud Gruber, professor at the University of Geneva, is trying to answer. And to do so, he studies not humans, but chimpanzees. Because the more we know about them, the more we know about us, he explains: “If you aren’t a creationist, you need to understand how human culture has developed exponentially and incomparably since the last common ancestor that we share with chimpanzees and bonobos, eight million years ago.”

Gruber’s original dream was to be a vet. But his interest in animal behaviour led him to study biology and cognitive sciences at the Ecole Normale Supérieure in France. After that, he went on to achieve a PhD in psychology at the University of St Andrews in Scotland. That was when he started to work on the behaviour of wild apes, with a particular focus on the way they use tools.

A honey trap, a stick and a sponge

Specifically, Gruber devised an experiment with a number of chimpanzee populations: a honey trap, consisting of a tree trunk with holes filled with honey and a handy stick to collect it with. Groups of apes who already use sticks in other situations use the one that is supplied, he explains. Other groups that are unfamiliar with sticks do not avail themselves of it. They apply the tool that they normally use to collect water: a handful of leaves that serve as a sponge.

Gruber’s observations enabled him and his colleagues to witness a new behaviour arising within a wild population – a rare event and a pivotal moment in a biologist’s career. “Some chimpanzees were used to using their leaf sponges to soak up minerals from clay pits. After a while, the leaves ran out, and the apes started to use moss from tree trunks to make sponges,” he says. The scientist and his team noticed that this behaviour was transmitted within the group by observation. “It was the missing evidence that made it possible to speak of culture in these animals – because one of the characteristics of culture is social transmission,” he explains.

From vocalisations to emotions

Since then, Gruber has broadened his field of research. For instance, he is interested in the low intensity vocalisations that apes produce: the sort of “hoo” that he readily compares to the sound that we humans make when we collapse onto the sofa after a long day at work. Whereas these ape sounds had been considered to be purely emotional and distinct from human sounds – which are intentional – Gruber was able to show that apes’ vocalisations are also produced for a specific audience and in a specific context.

Currently, as part of the project financed by the Swiss National Science Foundation (SNSF), he is looking into the role emotions play in the use of tools, in both apes and humans. For example, he would like to establish whether children learn more easily from a person with whom they have developed an emotional bond.

What about animal emotions? When asked about this, Gruber does not hold back. The subject is so close to his heart that he teaches it at the University of Geneva. “I think it’s essential to improve students’ knowledge in this area and to talk widely about it so that it feeds into discussions on animal welfare.” He also hopes that the scientific community will shed light on the question of animal emotions. This is not a settled issue: for some people, emotions are linked to language and therefore specific to humans.

An open-air laboratory

Gruber is also keen that his experiments with chimpanzees be conducted as far as possible in the field, to truly reflect their natural behaviour. “For them, being in captivity is a bit like us being in a retirement home – they need constant stimulation to keep boredom at bay. As a result, they’re more easily interested in our experiments, which makes comparisons with what happens in nature difficult.”

So for the last 15 years, he has been going to Uganda twice a year, to the scientific base that he runs in the heart of the Bugoma forest reserve. There, he monitors a chimpanzee population that he is slowly habituating to human presence in order to study them better. This habituation is starting to pay off. “When I was last there, two individuals made their nest on the ground five metres from me and my team, and then spent the night there – proving that they weren’t bothered by our presence,” he says with enthusiasm. A unique experience, indeed, but most of all he is looking forward to making faster progress in his research: because the days of monitoring wild ape populations are numbered, as these slowly disappear. “And the key to understanding who we are is disappearing with them,” he warns.

• Image for editorial use (JPEG). Caption: Thibaud Gruber © SNSF
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• Thibaud Gruber’s projects on the SNSF Data Portal