A 15-Million-Year-Old Clue in Ape Laughter May Reveal How Humans First Evolved the Ability to Speak

Great ape laughter carries an ancient rhythm humans still use.

What came first, speech or laughter?

A new study suggests that humans, chimpanzees, bonobos, gorillas, and orangutans share a basic laughing rhythm inherited from the last common ancestor that lived about 15 million years ago. The study offers a rare window into the deep roots of human speech, which left no fossils but may have grown from older forms of vocal control still heard in ape laughter today.

A Rhythm Older Than Language

The study compared laughter from four orangutans, two gorillas, three bonobos, four chimpanzees, and four human children, ages 6 months to 7 years. Researchers analyzed 140 laughter bouts recorded during play and tickling, measuring the timing between each burst rather than the pitch or loudness of the sounds.

Across all species, laughter showed isochrony—a regular beat, with similar time gaps between vocal bursts, like a biological metronome. In the study, this pattern appeared most clearly during tickling, while rough-and-tumble play produced more disrupted rhythms.

“How did humans evolve the remarkable ability to speak? Speech leaves no fossils, and complex language exists only in our own species,” Dr. Chiara De Gregorio said in the University of Warwick release. “But we’ve found a 15-million-year-old clue in an unexpected place: our laughter.”

To gather the sounds, researchers recorded spontaneous laughter during familiar, playful interactions in zoos and home settings. Human children were recorded during natural play with their mothers.

“It was striking,” De Gregorio told National Geographic. “Once you really focus on that, you see how similar it is to our kind of laughter.”

Faster, Looser, More Human

Human laughter was faster, more variable, and more flexible than the laughter of other great apes. Chimpanzees and bonobos, our closest living relatives, laughed faster than gorillas and orangutans. The researchers found that laughter tempo appeared to accelerate along the evolutionary tree.

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Humans also stood apart in how they changed laughter depending on context. A child’s tickle laugh differed from play laughter. In human adults, that flexibility becomes even richer.

“We are able to laugh in a polite way in front of the queen, but then when we are with our friends at the pub, we can laugh in a totally different way,” De Gregorio noted.

The researchers argue that this control over timing may resemble one of the building blocks of speech. Speech requires the brain, breath, and vocal tract to coordinate sounds with speed and precision. Laughter is certainly not the same as language, but it may point to the direction of the ancient biological machinery that would eventually give rise to the first speech sounds.

Before Words

Ape laughter is hard to record, especially from young individuals, so the sample was small. The researchers analyzed only 17 individuals in total.

Scientists can study skulls, jaws, hyoid bones, and other anatomical clues, but they cannot hear how extinct ancestors sounded. That makes living apes especially important. Their laughter offers a surviving behavior that humans also kept.

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“It is impossible to assess the precursor forms of language directly from our extinct ancestors,” Dr. Adriano Lameira, a co-author of the study and an associate professor in the Department of Psychology at the University of Warwick, said.

The study does not claim that laughter turned directly into speech. Instead, it suggests that the control needed for speech did not appear all at once in early humans. It may have developed gradually across millions of years in the ape family.

“Contrary to the classic notion that the first humans suddenly acquired vocal control capacities remarkably different from their predecessors, laughter evolution tells us that humans lie on a continuum, a prolongation of vocal control capacities that were already being cumulatively honed for 15 million years,” Lameira said, according to Discover.

For now, the finding gives an ordinary human sound a long ancestry. Every laugh may carry a beat that began long before words.

The study was published in the journal Communications Biology.