Every time you crack up, you may be echoing a rhythm that predates humanity itself. A new study from the University of Warwick finds that great apes — chimpanzees, bonobos, gorillas and orangutans — laugh with the same basic timing pattern as humans, a pattern the researchers believe was already present in the common ancestor we shared with them some 15 million years ago. The findings, published in Communications Biology, offer an unexpected new lens on one of evolution’s harder puzzles: how humans came to speak.

All living great apes laugh, but until now it has been unclear how that laughter changed — or didn’t — over millions of years, and what, if anything, it might reveal about the evolution of human speech. Speech itself leaves no trace in the fossil record, and complex language exists only in our own species, leaving researchers with few direct ways to reconstruct its origins.

Laughter offered the Warwick team a workaround. Because every living great ape laughs, comparing the structure of that laughter across species lets researchers peer further back in time than language alone would ever allow. The team analyzed laughter recordings from four orangutans, two gorillas, three bonobos, four chimpanzees and four humans, all captured during playful, tickle-induced interactions with familiar people in the animals’ and children’s own home environments. Across 140 individual laughter sequences, one pattern held steady regardless of species: each produced laughter with evenly spaced rhythmic intervals between successive sounds.

“How did humans evolve the remarkable ability to speak?” asked Dr. Chiara De Gregorio, an honorary research associate in Warwick’s Department of Psychology and the study’s lead author. “Speech leaves no fossils, and complex language exists only in our own species. But we’ve found a 15-million-year-old clue in an unexpected place: our laughter. Unlike speech, laughter is shared by all living great apes. By comparing how different species laugh, we can see that a basic rhythmic structure has remained unchanged since our last common ancestor. That’s extraordinary.”

The researchers argue that this underlying rhythm was likely already in place in the last common ancestor of all great apes, including humans, and that it has stayed remarkably conserved ever since — every living great ape still produces it today. What has changed, and changed substantially, is what humans do with it. Human laughter has become faster and more variable than that of our ape relatives, and humans alone have gained the ability to consciously shape when and how they laugh depending on context. An involuntary laugh triggered by tickling is acoustically distinct from the polite laugh offered in a meeting, the nervous laugh that follows an embarrassing mistake, or the contagious laughter that ripples through a group of friends — different social signals built on the same ancient rhythmic foundation, layered over with conscious control.

That layering, the researchers suggest, points to a broader story about how vocal control evolved across the ape lineage. If the rhythmic skeleton of laughter has stayed constant for 15 million years while the control exercised over it has grown more sophisticated, then the fine-grained vocal control that underlies human speech may not have appeared abruptly with the first humans. Instead, it looks more like the latest chapter in a long, gradual buildup of vocal flexibility that had already been underway for millions of years before speech itself emerged.

“It is impossible to assess the precursor forms of language directly from our extinct ancestors,” said Dr. Adriano Lameira, associate professor at Warwick’s ApeTank in the Department of Psychology. “Laughter, being evolutionarily older and having remained shared between all living great apes, provides a rare evolutionary window into the vocal transformations that unfolded across hominid evolution until the first humans appeared on scene. 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 lay on a continuum, a prolongation of vocal control capacities that were already being cumulatively honed in for 15 million years.”

The study’s design deliberately set aside two acoustic features that get most of the attention in laughter research — pitch and loudness — to focus narrowly on timing: the length of the pauses between one laughing burst and the next. That focus let the researchers compare laughter across species with very different vocal anatomies on a more level footing, since rhythm is less tied to the size and shape of an animal’s vocal tract than pitch or volume are.

The work builds on a body of earlier comparative research into the evolution of laughter across great apes, including foundational acoustic and phylogenetic analyses of tickle-induced vocalizations that first established laughter’s deep evolutionary roots in the hominid lineage. The new Warwick findings push that timeline further by isolating rhythm specifically, and by tying its conservation directly to questions about the gradual emergence of vocal control that speech eventually depends on.

For now, the laughter that breaks out at a family dinner or a comedy show carries with it a structure inherited from an ancestor none of us ever met — proof, in the researchers’ view, that some of the building blocks of human speech were already being assembled long before anything resembling language existed.

Endnotes
1. Chiara De Gregorio et al., “Rhythm and timing in laughter reveal that human vocal plasticity falls on a hominid continuum,” Communications Biology, June 25, 2026, DOI: 10.1038/s42003-026-10499-z.
2. University of Warwick, “Apes and humans have been sharing a laugh for 15 million years,” news release via EurekAlert!, June 25, 2026.
3. Marina Davila-Ross et al., “Reconstructing the evolution of laughter in great apes and humans,” Current Biology 19, no. 13 (2009): 1106–1111 — earlier phylogenetic evidence for shared laughter origins across great apes and humans.
4. Robert R. Provine, “Laughter as an approach to vocal evolution: The bipedal theory,” Psychonomic Bulletin & Review, 2016 — on laughter as a model system for studying the evolution of vocal control.