Dolphins Use Open-Mouth Expression to Signal Play
A new study finds bottlenose dolphins use a distinctive open-mouth facial display during social play, and playmates often copy it.
Updated on Nov. 8, 2026 in Wildlife
Researchers report in the journal iScience that bottlenose dolphins use an open-mouth expression during social play. When a playmate sees the expression, dolphins mirror it 33% of the time.
Why it matters
The findings suggest the open-mouth display functions as a play signal that may help dolphins avoid conflicts with other animals. It adds to evidence that dolphins communicate through visual cues as well as sound.
The study logged 1,288 open-mouth events, 92% of them during dolphin-dolphin play. Whether vocalizations or touch accompany the expression was not measured.
The players
University of Pisa
An Italian public research university whose researchers contributed to the study, with the senior author affiliated with the institution.
The details
Researchers recorded captive bottlenose dolphins playing in pairs and freely with human trainers, logging open-mouth events and measuring mimicry within a one-second window. Only a single event was recorded during solitary play, and dolphins almost always displayed the expression when a playmate could see them.
Timeline
The study was published on November 8, 2026, in the journal iScience.
Roadmap
The study extends research into dolphin communication by focusing on visual rather than acoustic signals. It points toward future work using eye-tracking to explore how dolphins perceive their social environment.
The findings clarify how dolphins signal intent during play, which may inform how people interpret animal behavior at aquariums and marine parks. Practical applications for the public remain limited until follow-up research on vocal and tactile cues is complete.
The takeaway
Playful facial signals can be a clear indicator of intent in social animals. Observers at marine facilities can use such cues to better read animal interactions.
Further reading
Explore more on Wildlife for related animal behavior coverage.
Source note: This article includes information reported by PlusNews.
