Deep in the forests of Southeast Asia, gibbons perform a dance — one that resembles a mix of robot and vogueing movements. The gibbons are dancing, but there is no music. Scientists now believe these silent, robotic performances may hold clues about the origins of dance.

The Silent Dancers

For years, gibbons have lived in the shadow of their more famous relatives — chimpanzees and bonobos — rarely drawing much scientific attention. But Kai Caspar, a zoologist at Heinrich Heine University in Düsseldorf, stumbled upon something remarkable while studying gibbons in zoos. He was observing how the apes reacted to their reflections in mirrors when they did something unexpected.

“The body becomes stiff, and then these robot-dance-like movements commence,” he said in an interview with the N, referring to the rhythmic swaying, dipping, and posing of the animals. The gibbons, particularly the females, were moving with intention, almost as if they were performing for an audience.

Performing for an audience

That simple observation opened a new chapter in the study of animal behavior. Dr. Caspar teamed up with primatologist Camille Coye from Paris and linguist Pritty Patel-Grosz from Oslo to dig deeper into the phenomenon. What they found — now published in the journal Primates — is that these robotic dances aren’t just quirky displays. They carry the hallmarks of something far more universal: dance.

The gibbons’ movements are unlike anything seen in other primates. When they dance, it’s with a distinct rhythm — almost mechanical, yet mesmerizing. They move their legs, arms, and even their rump in coordinated patterns. And, curiously, they check over their shoulders as they perform, as if making sure their audience is paying attention.

In the wild, female gibbons seem to dance for the males in their group, soliciting attention, grooming, and sometimes more intimate responses. In many of these cases, the male gibbon would react by grooming or mating with the female, Dr. Caspar noted. But in zoos, the behavior takes on new dimensions. The females perform for their human caretakers, swaying and posing as they wait for food or some other reward. And often, it seems, they just want to be noticed.

These are traits remarkably shared between human and gibbon dance. The researchers were especially intrigued by the intentionality behind the movements — the fact that the gibbons were clearly dancing for someone, whether another gibbon or a human. The dance wasn’t accidental. It was planned, with each movement following a rhythmic, almost metronomic beat.

Dancing across species

This pattern raises a tantalizing possibility. Could gibbons be offering us a glimpse into the evolutionary roots of dance?

Dance, in many ways, feels uniquely human. We dance at weddings, we dance in celebration, and sometimes we dance just because we feel like it. But we aren’t the only ones. Birds like peacocks and birds of paradise perform elaborate dance-like courtships to attract mates. Bees communicate through their intricate waggle dances. And, as it turns out, female gibbons — these lesser-known relatives of ours — are also swaying to their own beat.

What sets the gibbons apart is that, in most animal species, it’s the males who dance. In birds, fish, even insects, it’s typically males putting on elaborate performances to win over females. “It is also rare that in gibbons, it’s the females that dance, and not the males,” said Dr. Patel-Grosz. “This is not what we typically find in the animal kingdom.”

And then there’s the matter of sound — or rather, the lack of it. While human dances often go hand in hand with music, gibbons perform their rhythmic displays in silence. Even though gibbons are well-known for their elaborate vocalizations, their dances are notably quiet. “Gibbon dance is likely to be innate, while human dance is primarily determined by culture,” noted Dr. Caspar.

The evolution of dance

What makes gibbons dance? And why do only the females perform this robotic ritual? The researchers don’t have all the answers yet, but they have a few ideas. In the wild, the dances seem to be part of a complex social interaction, one that plays out between females and their mates. But in captivity, the reasons are less clear. Sometimes, the gibbons appear to dance out of frustration, perhaps in response to being confined. At other times, they seem to be dancing simply for attention.

What’s clear, though, is that this behavior — this rhythmic, structured, and intentional movement — shares fundamental traits with human dance. And while our last common ancestor with gibbons lived over 20 million years ago, researchers are intrigued by what these performances might reveal about the evolution of movement and rhythm in primates.

As Dr. Caspar sees it, gibbons deserve more scientific attention. “I really hope that this could help move them somewhat more into the spotlight,” he said. For now, the dancing gibbons remain an enigma — silent performers on a stage all their own, swaying to a beat that only they can hear.