A study has found that young chimpanzees develop distinct population-specific vocal patterns as they mature (ontogeny), challenging the long-held assumption that their calls are inflexible and determined solely by genetics.
Led by Queen Mary University of London in collaboration with the University of Portsmouth, the research published in PLOS One compared the vocalisations of infant and juvenile chimpanzees from two geographically separated populations.
By analysing grunts, whimpers and laughter, the team discovered that differences between the groups became more pronounced as the animals grew older, suggesting that vocal behaviour continues to develop throughout early life.
Analogously to people - who recognise different regional accents - the team found that young chimpanzees from different communities produced subtly different vocal patterns too. Moreover, some population-specific vocal characteristics were already present in infancy, while others emerged during the juvenile years. This developmental pattern suggests that social interactions, environmental conditions and other non-genetic influences may all contribute to shaping how young chimpanzees communicate.
The findings provide the first evidence that population-specific vocal differences become increasingly distinct during chimpanzee development. By focusing on how communication changes over time, rather than simply comparing adults from different populations, the research offers a new perspective on the processes that shape vocal behaviour in other species.
"Understanding how communication develops during early life is fundamental to understanding animal behaviour. Our findings show that chimpanzee vocalisations are not simply fixed from birth but continue to develop as young animals interact with their social and ecological environments," said doctoral researcher Kassandra Giragosian from Queen Mary University of London, who led the research.
The research contributes to a growing body of evidence that primate communication is more flexible and dynamic than previously recognised. By examining vocal development through an ontogenetic lens, the study provides a valuable framework for investigating how communication systems emerge and diversify within animal populations.
Although the study does not suggest that chimpanzees possess language or human-like speech - a process that involves agreed grammar and lexicon, for instance - but it convincingly demonstrates that their vocal development is influenced by more than genetics alone. By showing that population-specific vocal patterns emerge and become more pronounced during development, the research provides new insight into the biological and environmental factors that shape communication in primates and offers a fresh perspective on the evolution of complex communication systems.
The study was co-authored by Dr Marina Davila Ross , Associate Professor in Comparative Psychology at the University of Portsmouth, and Derry Taylor of the Institute of Cognitive Sciences Marc Jeannerod.
The findings add to a growing body of work from Dr Davila-Ross exploring the deep evolutionary roots of primate communication. In June, she co-authored a separate study in Communications Biology , which showed great apes may have been laughing with a similar rhythm to modern humans for over 15 million years , providing an unexpected clue to how human speech evolved. Before that, she worked on research demonstrating that orangutans and chimpanzees mirror one another's laugh faces with remarkable precision during play - a level of facial communication exactness previously thought to be uniquely human.
