Young chimps develop 'accents' in their communication language just like humans

Families leave fingerprints on voices in every culture, yet few researchers had checked if that pattern holds with wild chimpanzee mothers and their offspring.

A new field study says it does, and the clue is in the way apes braid sounds with tiny shifts of body and gaze.

The authors spent months with one Ugandan community and discovered that a youngster’s communication “accent” almost always matches the maternal line, not the paternal one.

Joseph Mine of the University of Zurich and colleagues report the findings.

Studying chimps and their mothers

The research unfolded in Kibale National Park, a mosaic of rainforest and grassland covering about six square miles of chimp range.

Twenty-two Pan troglodytes older than ten were followed from dawn to dusk while observers captured every vocalization on high-definition video.

Grunts, pant hoots, barks, and whimpers by chimps and their mothers were cataloged alongside arm waves, posture changes, and eye direction, generating over one hundred distinct vocal-visual pairings. Custom software then counted combinations from 210 communication events.

Bouts could last from a single second to about a minute, and the team noted that longer calls often carried more accompanying signals.

Even after controlling for call duration, kin related through mothers still produced strikingly similar combination rates, while paternal kin did not.

When the data were plotted against the family tree, tight matriline clusters appeared, whereas paternal relatives scattered like tossed seeds. That neat divide suggested learning, not genes, was steering the communication style.

What chimps learn from mothers

Chimp calls may sound repetitive to outsiders, but meaning changes with context. A low grunt plus a relaxed shoulder invites cooperation, the same sound paired with a rigid stare warns rivals to back off.

“What we see is that certain chimpanzee mothers tend to produce many vocal visual combinations, while others produce few, and the offspring end up behaving like the mothers,” said Mine.

Mothers spend thousands of hours within arm’s reach of their offspring, offering a nonstop master class in timing and emphasis. 

The influence lasts well into adolescence: every subject in the study had passed ten years of age, yet still reflected the maternal template.

Such durability mirrors tool use traditions, nest building tricks, and foraging routes that young chimps pick up from mom and keep for life.

Humans follow a similar path. Brain imaging work shows that infants’ auditory maps sharpen in direct response to speech from caregivers, underscoring the power of social tutoring during the first year of life.

Why chimps don’t copy fathers

Male chimpanzees patrol borders, join hunting parties, and spend nights in separate trees, limiting close range contact with infants. With few intimate moments to watch dad gesture, youngsters have little chance to copy his style.

Genetics offers no easy alternative. Maternal and paternal kin share similar fractions of DNA, and the vocal apparatus does not differ by parentage. Mine’s group even considered X linked inheritance yet found no sex bias in the pattern.

The maternal stamp shows up in other behaviors as well. A Harvard University team showed that only lineages whose mothers clasped hands overhead during grooming kept doing so decades after the elder female died.

Intriguingly, some theories suggest that mitochondria or sex chromosomes could influence brain circuits for communication, but these ideas predict stronger mother son resemblance than mother daughter, which the new data do not support.

Lessons for human language

Face to face conversation is not just words. Medical education data place verbal content at roughly seven percent of the total signal, with tone and body language conveying the rest.

The findings remind us why chimps and toddlers learn from their mothers as they watch lips, hands, and posture as closely as they listen.

“In humans, body language includes hand gestures and facial expressions, but also many subtle behaviours, like shifts in posture and gaze direction,” noted Simon Townsend, a senior author. 

Gesture vocabularies differ across cultures, from the Italian hand pinch to the American thumbs up, showing that social learning sculpts non verbal codes in our species as surely as it does in chimps.

Recognizing gestures as learned may even aid conservationists. Playback experiments that rely only on audio could miss half the picture, potentially stressing animals by stripping away the visual layer that normally softens or sharpens a call’s intent.

What other chimp studies found

Evidence for vocal learning in apes was once considered thin. Early work focused on fixed call repertoires, yet modern recordings reveal surprising flexibility.

In Côte d’Ivoire, neighboring communities craft distinct pant hoot accents even when habitat and diet match closely, suggesting they tweak calls to flag group identity.

Captive experiments add another layer: one colony invented a novel food grunt that swept through the enclosure within weeks, proving how quickly social transmission can reshape signals.

Fresh data also show chimps using gestures to coordinate a cultural ritual called grooming handclasp, where partners raise arms and clasp hands overhead.

Researchers found that silent gestures triggered the move in 44 percent of cases, confirming that body language can lead group traditions.

Chimps, mothers, and language

If a chimp can pick up a gestural dialect from mom, the roots of human speech may reach deeper into evolutionary history than textbooks once claimed.

Socially learned communication could have begun as a simple maternal bond and later expanded into the complex phonetic systems humans wield today.

“The next exciting step will be to see if offspring are learning certain types of visual vocal combinations from their mothers, in addition to the number of visual behaviours they produce when they vocalise,” said Katie Slocombe, University of York.

Long term projects across multiple sites will be essential. Comparative work with bonobos, whose social order differs markedly from chimps, could reveal whether maternal imprinting is a great ape signature or a chimpanzee specialty.

Cultural historians of language note that every human generation puts its own twist on speech, slang, and cadence.

The new ape data suggest that this creative cycle may have started millions of years before the first words were spoken.

The study is published in PLOS Biology.

—–

Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates. 

Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com.

—–