Bonobo Jill fiddles with a blue barrel with a red lid. She has to get her meal of straw out of the barrel through a small hole. It causes a lot of rumbling and fiddling. Bessede watches quietly from the corner of the indoor enclosure, while he chews on some grass. “Isn’t it great, this image,” says Evy van Berlo, who obtained her doctorate from Leiden University, is now a comparative psychologist at the University of Amsterdam and specializes in the behavior of great apes. “We sometimes think that animals just do whatever, but it’s not all instinct.”
Van Berlo was here almost every day between 2016 and 2018. In the bonobos’ abode (Pan panic) in the Apenheul was her research set-up: a tablet with two photos of a monkey with emotions and one without. “The monkeys could click on a dot that appeared behind one of the two pictures. For example, we saw that they were faster in touching the dot if it appeared behind an emotional photo.” Secretly Berlo had expected that too. “But we also made a distinction in those photos between known and unknown monkeys. The bonobos responded much faster to emotional faces of strangers than to those of acquaintances.”
It confirms previous hypotheses: the bonobo is a xenophile species, with a preference for congeners it does not know. Bonobos are tolerant animals. In the wild they share their food with peers because they live in a fairly stable environment in the wild. And for the conservation of the species, it is beneficial to share everything nicely.”
The bonobos of the Apenheul are also friendly. “I felt really honored that they allowed me to peek into their lives. Often I greeted them with a nod, and they nodded back. Some even approached me when they saw me.” In the country house there is little of the brands. The monkeys barely move and huddle with their heads between their knees: “I think they’re cold.”
‘Very close to us’
The passion for the animals can be read from Van Berlo’s face. With a broad smile she points to certain patterns in the fur, hand movements and body posture of the Apeldoorn bonobos.
Her love for great apes started during her master’s degree in neuroscience and cognition at Utrecht University. She attended a lecture by Liesbeth Sterk, professor of behavioral biology there: “She researched friendships between monkeys. At first I thought I couldn’t, because well, you have to be a behavioral biologist for that, and I simply wasn’t. But yes, now we are here.”
Where it started for Van Berlo as a ‘simple’ fascination, she found more and more arguments to study great apes: “First of all, they are very close to us in terms of evolution. The behavior of those animals provides a unique insight into where we come from.” According to Van Berlo, it is often wrongly assumed that all reason and ‘real’ intelligence started with humans, but given the slowness of evolution, this is actually impossible, according to her. “By doing research on bonobos, I show that we humans are really not that special. Bonobos also make choices, show emotions, consult with each other. They’re like humans, or yes, we’re like monkeys.
“We have sent rockets to the moon and developed medicine, but at the same time we are polluting our planet and waging primitive wars. On the one hand we humans can work very well together, on the other hand we show a lot of intolerance towards each other. You also see these properties in great apes. By studying emotions, choices and other cognitive skills of monkeys, we learn to understand ourselves better.”
Swiping chimpanzees
In addition to a better understanding of ourselves, the bond between humans and animals is also a driving force for Van Berlo. “I am quite concerned about the decline of animal species, for example bonobos. They only live in the jungle of the Democratic Republic of Congo. That population is already very small. If something happens in that area, for example massive tree felling, then they will probably die out. By gaining a better understanding of how these animals think, why they do what they do and what emotions they show, people may realize that we can’t just make them disappear.”
She mentions the information boards in the zoo: “You often see what the animals eat, where they live in the wild, how long they sleep, you name it. But how they think is missing. What are the emotions of animals? How do they show that? Our research is essential for this.”
Her research in the Apenheul has now been completed. Van Berlo is currently working on new research into chimpanzee cognitive skills (Pan troglodytes) in Arts. She shows a video of a chimpanzee operating a tablet with his finger: “We let them ‘loose’ them in a digital field and they have to look for apples there. If they find one in the game, they get a piece of apple in the real world. They invented all by themselves how the game works. We grew up with technology, but they’ve never seen a tablet like this. Pretty clever, isn’t it, those monkeys?”