WASHINGTON, OCT 3 – Bottlenose dolphins use friendly facial signals to show non-hostile intent to their playmates and those signals are reciprocated in kind, according to a study published in the journal iScience, yesterday.
The discovery was made by evolutionary biologist Elisabetta Palagi from the University of Pisa, who discovered that these intelligent marine mammals use visual cues similar to humans when communicating during play.
Palagi and his fellow researcher, Livio Favaro of the University of Turin, initially noticed this behavior by chance while observing dolphins at play. “We found that dolphins often open their mouths in front of each other without biting, which is a sign of the start of play,” Palagi told AFP.
They then carried out further studies to see if the cues were intended to prevent play from turning into actual fights, which involve activities such as acrobatics, chasing, playing with objects and tail slapping.
Although many other animals such as primates and bears have long been known to use the open-mouth movement as a sign of play, there is no strong evidence that dolphins do the same.
To confirm the findings, the researchers recorded hundreds of game sessions among the dolphins bottlenose in facilities in Italy and France, where it plays in pairs and interacts freely with human trainers. The study found that dolphins often show ‘smiles’ when interacting with their mates, and this signal rarely occurs when they are alone or with humans. – AFP
