What’s so funny? Apes and humans have been sharing a laugh for 15 million years

All living great apes - chimpanzees, bonobos, gorillas, and orangutans - laugh. But until now, it has been unclear how our laughter may have changed over millions of years of evolution, and how it might relate to the evolution of our speech. 

New research from the University of Warwick and University of Portsmouth shows they share the same fundamental rhythmic pattern in their laughter as humans, suggesting this feature was already present in their common ancestor 15 million years ago.  

The study, published in Communications Biology, analysed laughter recordings from four orangutans, two gorillas, three bonobos, four chimpanzees, and four humans. Across 140 laughter sequences, they found the same pattern: all species produce laughter with evenly spaced rhythmic intervals between successive sounds. 

The researchers propose this basic rhythmic laughing structure was already present in a shared common ancestor 15 million years ago and has remained remarkably conserved with all living great apes and humans still showing the same underlying pattern in their laughter.

Dr Marina Davila Ross, co-author and Associate Professor in Comparative Psychology at the University of Portsmouth, said: “Laughter is evolutionarily older than speech, and it's shared by all living great apes. By looking at how different species laugh, we can trace a continuous thread of vocal development stretching back long before the first humans appeared. 

“This research shows that the vocal control we think of as distinctively human didn't emerge suddenly. It was already being built, step by step, across hominid evolution. Laughter gives us a rare and rather positive way to see that.” 

However, while the basic rhythm stayed constant between species, the researchers did find that human laughter has become faster, more variable, and has gained sophisticated context-dependent control over time. 

Of the great apes, humans alone have the ability to control when and how they laugh depending on context: an uncontrollable laugh when tickled differs sharply from a polite laugh in a meeting, a nervous laugh after a mistake, or the infectious laughter that spreads through a group of friends. The same underlying rhythm, shaped by conscious control to communicate different emotions and intentions. 

The findings of this study suggest that throughout great ape evolution, our ancestors gradually developed greater control over the timing of their vocalisations, including laughter – showing a fundamental building block of speech. 

Lead author, Dr Chiara De Gregorio, Honorary Research Associate at the University of Warwick, added: “How did humans evolve the remarkable ability to speak? 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 findings add to a growing body of work from Dr Davila-Ross exploring the deep evolutionary roots of primate communication. In April, she co-authored a separate study in Scientific Reports demonstrating that orangutans and chimpanzees mirror one another's laugh faces with remarkable precision during play - a level of facial communication exactness previously thought to be uniquely human.