Dolphins smile at each other while playing, study says
Bottlenose dolphin calf, smiling big, at six months, Tursiops truncatus, Dolphin Academy, Seaquarium, Curacao, Netherlands Antilles, (Photo by Wild Horizons/Universal Images Group via Getty Images)
Dolphins are actually smiling at each other when they open their mouths while playing with one another, according to a recent study out of Italy.
Visual communication is important for animals too
Playful visuals help with communication among dolphins, especially during play time, according to researchers. This is not unlike human behavior.
"We've uncovered the presence of a distinct facial display, the open mouth, in bottlenose dolphins, and we showed that dolphins are also able to mirror others' facial expression," senior author and evolutionary biologist Elisabetta Palagi of the University of Pisa said, according to Phys.org.
It’s been documented among other mammals that facial expressions play a crucial part in communication, but this is the first time it has been observed in dolphins, researchers claimed.
Open mouth = smiling
A total of 22 dolphins that belonged to four social groups were observed.
"The open mouth gesture likely evolved from the biting action, breaking down the biting sequence to leave only the 'intention to bite' without contact," Palagi said. "The relaxed open mouth, seen in social carnivores, monkeys' play faces, and even human laughter, is a universal sign of playfulness, helping animals—and us—signal fun and avoid conflict."
Researchers recorded dolphins in captivity as they played in pairs, as well as interacted with their human trainers, according to the study.
Researchers also reported 1,288 open mouth events during their social play time.
The dolphins would frequently use the open mouth expression with other dolphins but not as much with humans.
"Future research should dive into eye-tracking to explore how dolphins see their world and utilize acoustic signals in their multimodal communication during play," co-author and zoologist Livio Favaro, said.