Overview
- A peer‑reviewed paper in Communications Biology reports that humans, chimpanzees, bonobos, gorillas and orangutans produce laughter with evenly spaced intervals, a pattern the authors trace to a common ancestor about 15 million years ago.
- The team analysed 140 laughter bouts and 458 gaps between laugh sounds from 17 individuals drawn largely from archival zoo recordings and human home recordings, covering tickling and rough‑and‑tumble play contexts.
- Tickling produced the clearest, most regular rhythmic signal because it disrupts breathing less than rough play, which often distorts timing through twisting and chest compression.
- Humans were the only species to alter laugh tempo by context and showed the greatest tempo variability, which the authors interpret as evidence of increased voluntary vocal control along the human lineage.
- The study’s small, heterogeneous and mostly captive sample limits species‑level claims, and the authors call for larger, wild and age‑diverse datasets to confirm the rhythm, test evolutionary inferences and explore links to speech.