Dolphins, particularly bottlenose dolphins, have demonstrated the ability to perform a social "smile" that is used to invite other dolphins to play. That's according to a new study published in the journal iScience that sheds light on the complex social interactions of these intelligent marine mammals.
It is noted that biologists from the University of Pisa (Italy) discovered that bottlenose dolphins use a facial expression similar to a smile to show others their desire to play together a little.
Dolphins love to play by jumping out of the water, riding the waves, playing with things in the water, chasing each other and pretending to fight. An invitation to these games can be an open mouth, which scientists consider an analogue of a human smile. Other members of the group often respond with a similar "mimic".
We discovered the presence of an expressive face, an open mouth, in bottlenose dolphins, and we showed that dolphins are also able to mirror the facial expressions of others. Open-mouth signals and rapid facial expressions appear repeatedly in the mammalian family tree, suggesting that visual communication has played a critical role in shaping complex social interactions not only in dolphins but in many species,
Scientists also discovered an interesting pattern. Although dolphins are willing to interact with humans, they used the "smile" only when communicating with each other, but not with humans. When a dolphin is alone, it does not "smile" either.
The researchers recorded 1,288 “smiles” when the dolphins played together, and only one when the dolphin played alone.
The open-mouth gesture probably evolved from biting, disrupting the sequence of biting to leave only the “intention to bite” without contact. The relaxed, open mouth seen in social carnivores, the playful faces of monkeys and even human laughter is a universal sign of playfulness, helping animals – and us – to show fun and avoid conflict.
