Chimpanzees use gestures, vocalizations and facial expressions similar to those of human babies, according to new research.
They share the same “sign language” – despite being separated from a common ancestor that roamed Earth 10 million years ago.
It’s the first evidence of intentional communication outside human language. They serve multiple purposes, from initiating grooming and contact – to sexual intercourse.
Psychologists found it helps them be better understood in different situations – such as during playing or fighting.
The ability develops throughout infancy and adolescence, says the Durham University team.
Lead author Dr. Emma Doherty explained: “When we think about human language, we know it’s a combination of different types of communication such as speech, facial expressions and gestures.
“The way we communicate likely has deep evolutionary roots that are shared with some of our closest living relatives, such as apes.
“Our study provides evidence the way chimpanzees communicate with increased complexity as they get older is consistent with the development of communication we see in human infants.
“By studying the development of this multi-layered way of communicating among young chimpanzees we can learn more about the reasons behind this and shed light on the potential evolutionary continuity between humans and other apes.”
It suggests primate gestures with shared meanings extend to humans – and could be biologically inherited.
The findings in Animal Behaviour are based on observations of 28 semi-wild individuals, ranging in age from one to 11 years old, at the Chimfunshi Wildlife Orphanage Trust sanctuary in northern Zambia.
Previous studies on apes have largely looked at different forms of communication signals in isolation – gestures, vocalizations and facial expressions.
Dr. Doherty and colleagues looked at how chimpanzees combined them – revealing for the first time how they develop.
They found our closest cousins consistently used standalone signals – such as grunting, arm movements or facial expressions – across all ages and in different situations.
But as they got older, they were more likely to combine different communication signals together.
This was especially the case when responding to aggression or being playful – circumstances where it’s important to make clear what they were communicating to avoid risky fallout.
Adolescents were also more likely to use a combination of different communication signals instead of individual gestures or expressions, especially during aggression scenarios.
The researchers call for more research into multimodal signals in primates in the wild to further understand how the development of communication is affected by different environments.
It could shed light on how communication develops in apes and potentially help us to understand the evolution of human communication.
Added corresponding author Professor Zanna Clay: “A lot of the focus of research so far into communication, both in humans and other animals, looks at individual communication signals independently, but we know humans combine these signals all the time from early infancy.
“As a close relative of humans, apes give us a snapshot into how these signals could have evolved into multimodal communications, ultimately culminating in human language.”
Chimpanzees share around 96 percent of human DNA. Like humans they have complex emotions, a high level of intelligence, unique finger prints and even a sense of humour.
Numbers have plummeted in West Africa in the last 25 years. They are now classified as critically endangered species.
Wild chimpanzee mothers are killed for bush meat and their babies are sold as high-value pets.
Produced in association with SWNS Talker
Edited by Fatima Khalid and Saba Fatima
