Students discover chimpanzees make rhythmic sounds (despite limited sense of rhythm)
How can chimpanzees, so closely related to humans, have almost no sense of rhythm? ‘The best students ever’ and behavioural biologist Michelle Spierings demonstrated that chimps can actually drum and move rhythmically—each following their own unique beat.
Chimpanzees dislike the cold, and so do most humans, but biology students Veerle Hovenkamp and Bas van der Vleuten didn’t let that stop them. From the chilly early days of spring to the wet autumn of 2023, they spent countless hours observing chimpanzees—six weeks at Beekse Bergen in spring and later at Burgers’ Zoo in autumn, with cameras and microphones capturing the chimps’ behaviours.
Drumming on hollow trees for up to ten seconds
What started as a bachelor’s project culminated in a scientific publication in December. The research focused on rhythmic movements, known as ‘display behaviours,’ of our closest living relatives. These displays include drumming on hollow tree trunks for up to ten seconds—sometimes to express tension, resolve conflicts, or even as a show of power. Chimps in the wild use such displays to communicate within groups.
Drumming towards others is less rhythmic
Hovenkamp explains: ‘We documented 132 displays from 29 individuals during 90 hours of observation. Many of the unguided displays occurred against iron doors in their enclosures, likely because they produced the loudest sound.’ Analysis of all these displays showed that each chimp has its own rhythm, though interactions with others often deviated from those individual patterns.
Human babies develop rhythm awareness within the first days of their lives
Research leader Michelle Spierings is excited about these new findings. She studies language perception in various animal species, including budgerigars, zebra finches, and parrots, focusing on their communication and learning processes. Alongside her work in Leiden, she runs a lab in Vienna studying common marmosets. While travelling to Vienna, she explains: ‘Primates are fascinating because they are closely related to us in evolutionary terms, while birds are intriguing because their abilities – such as singing rhythmically and learning from others—mirror some of our own.’
Although primates are so closely related to humans, they differ significantly in language and rhythm perception. ‘Primates aren’t particularly strong auditory learners. Chimpanzees struggle to recognise rhythm,’ Spierings says. By contrast, human babies display brain responses to unexpected rhythmic changes just days after birth. This study shows that chimpanzees do use rhythm in their communication, though the reason remains unclear. ‘Perhaps rhythmic sounds or movements are simply the most energy-efficient way to make noise,’ she suggests.
‘Getting to know these animals was amazing’
When the students started their internship at Beekse Bergen, Spierings called them ‘two of the best students ever.’ Their work even laid the foundation for a scientific publication. Spierings notes: ‘For that to happen, it was crucial to study another group of chimpanzees.’ This led to a follow-up research at Burger’s Zoo. Reflecting on the experience, Van der Vleuten says: ‘Getting to know these animals was truly special. Over time, you see the bonds between the chimps and the unique personality of each individual.’
‘For the first time, others were interested in our work’
Taking their first steps into research proved inspiring for the students. Hovenkamp recalls: ‘The highlight was presenting at a conference of the Dutch Society for Behavioural Biology. For the first time, we weren’t just students listening — others genuinely cared about our findings.’ Van der Vleuten adds: ‘Capturing the first major display on film or seeing the initial results come in were moments that stayed with me, as did the first and last times seeing the animals.’
For a long time animal language didn't interest us that much, now it's hot
Interest in animal language is growing. For example, last year it was discovered that elephants call each other by name, while lions yawn together before collectively moving to a new resting spot. Spierings notes: ‘It’s only in the past two decades that we’ve seriously studied language perception in animals. It’s a challenging field—observing and analysing takes a lot of time, and there’s always the risk of anthropomorphism, interpreting animals in overly human terms.’ She hopes this growing recognition of similarities between humans and animals will lead to better protection for wildlife.
The two students have been captivated by their research. They are now pursuing master’s degrees in Environmental Biology at Utrecht University, specialising in behavioural ecology. Hovenkamp says: ‘In February, I’ll be heading to Zambia to observe even more chimpanzee behaviour for my master’s research on the origins of culture. I’m incredibly excited!’