Chimpanzee raspberry calls follow a learned convention, study of 91 apes suggests

Across 91 chimpanzees in eight groups, the lip-sputtering “raspberry” call had one settled use only where adults were around to copy, a pattern the authors call a learned signal convention.

Peer reviewed · Observational (quasi-experimental) study · Newcomer effect based on one case

Chimpanzees appear to pick up from the adults around them when to blow a “raspberry”, a sputter made with the lips. A team led by Antoine Valet and Catherine Crockford at the CNRS Institute of Cognitive Sciences in Lyon compared 91 chimpanzees in eight groups and published the results in PNAS on 9 November 2026. Groups with adult role models used the call in one stable context. Orphan groups without adults used it in many shifting ones. The authors call that a learned convention. The comparison is observational, and its most direct test rests on one adult joining one group.

Evidence at a glance

Is this a big deal?

It is a solid step for one family of calls and an early one for the bigger claim. The researchers say learned, agreed use has not been shown in chimpanzee calls before. Their case rests on a comparison nobody controlled and on one newcomer, and it stops short of saying chimpanzees have words or language.

What scientists found

The study looked at unvoiced calls: sounds made with the lips and breath, with the raspberry as the best-known example. In communities with adult role models, the abstract reports, these calls were given in “one dominant context”. That use stayed the same over years and was already in place in a chimpanzee’s first calls, at 1 to 2 years old.

Groups without role models looked different. Their use of the same calls was “highly variable” and changed across contexts and from year to year. The University of Warwick’s release fills in the contexts: wild chimpanzees at Taï used the raspberry almost only while grooming others, and juveniles at the sanctuary used it across a much wider range of social situations.

The abstract reports two checks. Age did not explain the variation, and neither did a shared emotional tone: the varied situations were not simply all pleasant or all tense. Individuals could also use different forms of unvoiced call in the same situation, so the sound and its use came apart.

From this the authors argue the calls meet three tests for a convention: the link between sound and use is arbitrary, it is passed on socially, and it is stable within a community.

How they found it

No researcher can ethically raise a chimpanzee without adults to see what happens to its calls. Circumstance had already done that. At Tacugama Chimpanzee Sanctuary in Sierra Leone, orphaned chimpanzees grow up among their peers. In Taï National Park in Côte d’Ivoire (Ivory Coast), wild youngsters grow up among adults. The paper calls the comparison a “quasi-experimental design”.

The team collected audio recordings and notes on what was happening around each call in four groups at each site, covering animals from newborns to a 55-year-old. Warwick’s release gives the reasoning: a purely instinctive call should be used in similar ways wherever a chimpanzee grows up. It wasn’t.

Then came a natural test. According to the release, an adult chimpanzee was introduced to one of the sanctuary groups, and over time that group’s use of the raspberry became more consistent and began to resemble the newcomer’s. The releases describe one such introduction.

Why it matters to you

This won’t change anything in your daily life. Its pull is curiosity about how much of what we do when we talk is older than our species. Think of which side of the road people drive on. Left or right would work equally well; what matters is that everyone around you does the same, and you learn it from them. The comparison has limits. Road rules are written down and enforced. The chimpanzee pattern is a regularity seen in recordings, and the study does not show that chimpanzees are aware of any rule.

Richard Moore, a University of Warwick philosopher and co-author, made the link to speech in the release. People use the words they do because their peers do. “It’s communal practice that fixes their meaning,” he said.

What the evidence does not show

It does not show that chimpanzees learn new sounds. Both releases say chimpanzees struggle with entirely new call sounds, and orphans with no adults around still made the raspberry. What appears to be learned is when to use it.

It does not isolate role models as the cause. Wild and sanctuary chimpanzees also differ in where they live, how much contact they have with people, and whether they lost their mothers early. The abstract rules out age and shared emotional tone. SciQuest could not read the full paper, so we cannot say how it handles the other differences.

The newcomer result is the closest thing to a before-and-after test, and it is one adult in one group. A single case cannot exclude other changes in that group over the same period, and the releases give no dates, call counts or group sizes for it.

The authors raise one puzzle themselves. If the use is learned and arbitrary, it is odd that different populations use the raspberry in similar ways. Crockford suggests in the release that chimpanzees already use their lips to pick parasites from fur, which may make a lip sound easy to produce, and that communities could have arrived at this independently. She says that idea needs testing.

How this fits what we already knew

For years the raspberry was mostly a captive-chimpanzee story. In 2007 William Hopkins, Jared Taglialatela and David Leavens reported in Animal Behaviour that captive chimpanzees appeared to use the raspberry to get a human’s attention, and described it as a captivity-specific signal. The new study records it in wild communities at Taï, where it goes with grooming. Taï’s forest is also where a separate project filmed sooty mangabeys flexing their feet as they climb.

Field evidence for learning was thinner. In 2016 David Watts described four distinct sounds that chimpanzees at Ngogo, Uganda, make while grooming. Maternal relatives were more alike in their use of two of them, which hinted at social learning, but Watts called the results “not conclusive” and said possible grooming-sound dialects deserved further study. The new paper adds two things that study lacked: groups with no adults to learn from, and records spanning years. For a signal whose effect depends on who in the group gives it, see the 2017 study of African wild dogs sneezing before a hunt.

Independent view

SciQuest found no on-record comment from a researcher outside the study team as of 10 November 2026 and was unable to request one during this automated run. The one news report we found quoted only the paper’s authors.

How other headlines framed it

The University of Warwick headline calls the result the first evidence of learned vocal conventions in great ape communication. The Max Planck release leads with chimpanzees learning when to use some calls, and a parallel to how children learn words.

Popular Science framed it around babies blowing raspberries because adults do it first, with a subheading about learning new sounds. The study’s claim is narrower: orphans without adults made the sound too, and the reported difference is in when the call is used. SciQuest’s headline says “suggests” because the design is observational.

What happens next

The authors’ next question is why different populations use the raspberry so similarly. More introductions of adults into peer-raised groups, recorded before and after, would show whether the newcomer effect repeats. Roman Wittig, who directs the Taï Chimpanzee Project, said in the release that this research depends on wild chimpanzee populations surviving. We will update this story if independent researchers respond.

In one sentence

In a study of 91 chimpanzees, groups with adults used the raspberry call in one stable way and adult-less orphan groups did not, which suggests the call’s use is a learned convention, though the evidence is observational and leans on one newcomer.

Read next

• How African wild dogs use sneezes before a hunt: a signal that works at the level of the pack.
• Monkey feet complicate a key assumption about human evolution: what wild primates at Taï can and cannot tell us about our past.
• Fish schooling evolved about 60 times and was lost about 320: how a group-only behaviour comes and goes over evolutionary time.

Sources and disclosure

1. Valet A., Moore R., Bortolato T., Kleinhause G. Gedalyahou T., de Witasse-Thézy A., Girard-Buttoz C., Wittig R. M., Crockford C. “A signal convention in natural chimpanzee communication.” PNAS 123 (47): e2606837123 (2026). doi:10.1073/pnas.2606837123. Open access (CC BY 4.0).
2. University of Warwick, 10 November 2026: Chimpanzees blowing raspberries offers first evidence of learned vocal conventions in great ape communication.
3. Max Planck Institute for Evolutionary Anthropology, via EurekAlert, 9 November 2026: Chimpanzees learn when to use some of their calls.
4. Hopkins W. D., Taglialatela J., Leavens D. A. “Chimpanzees differentially produce novel vocalizations to capture the attention of a human.” Animal Behaviour 73 (2): 281–286 (2007). doi:10.1016/j.anbehav.2006.08.004.
5. Watts D. P. “Production of grooming-associated sounds by chimpanzees (Pan troglodytes) at Ngogo: variation, social learning, and possible functions.” Primates 57 (1): 61–72 (2016). doi:10.1007/s10329-015-0497-8.
6. Popular Science (Laura Baisas), 9 November 2026: news report on the study, read for the framing comparison only.

Disclosure: This article was drafted with AI assistance and checked against the sources above. The full text of the PNAS paper was blocked to automated access; SciQuest read the paper’s abstract, author list, affiliations and dates through Crossref, and relied on the University of Warwick and Max Planck releases for the grooming context, the newcomer observation and the quote. No calculations were needed. The graphic is a SciQuest original with schematic dot patterns, and no third-party images are used. The Max Planck release lists the Max Planck Society and the Leakey Foundation as funders. Spotted an error? See our corrections policy.