Play is a widespread behavior in distant species, and its social form relies on complex communication. Playful communication has been largely ignored in marine mammals. In a new study, scientists from the University of Pisa focused on playful visual communication. bottlenose dolphin (Tursiops truncatus).
“We revealed that bottlenose dolphins have a unique facial expression of open mouth, and showed that dolphins can also mirror other people’s facial expressions.” Dr. Elisabetta Palagian evolutionary biologist at the University of Pisa.
“Open-mouth cues and quick imitations are repeated throughout the mammalian family tree. This shows that in many species, not just dolphins, visual communication is important for forming complex social interactions. This suggests that it has played a role.”
Dolphin play includes acrobatics, surfing, playing with objects, chasing and fighting, but it is important that these activities are not mistaken for aggression.
Other mammals use facial expressions to convey playfulness, but it has not been investigated whether marine mammals also use facial expressions to signal play.
“The mouth-opening gesture probably evolved from the chewing motion, breaking down the chewing sequence to leave only the ‘intention to bite’ without contact,” Palagi said.
“The relaxed, open mouth seen in sociable carnivores, the playful faces of monkeys, and even the laughter of humans is a universal sign of playfulness and signals enjoyment to animals, and to us. , helps avoid conflict.”
marieri others. They investigated the presence and possible functions of open-mouth displays in solitary play, interspecific (human-dolphin) play, and intraspecific free play. Image credit: Marieli others., doi: 10.1016/j.isci.2024.110966.
To investigate whether dolphins visually communicate playfulness, Dr Palagi and colleagues studied captive bottlenose dolphins when they were playing in pairs and when they were playing freely with a human handler. recorded.
They showed that dolphins frequently use the open-mouthed expression when playing with other dolphins, but do not seem to use it when playing with humans or alone. .
Although only one open-mouth incident was recorded during solitary play, the researchers recorded a total of 1,288 open-mouth incidents during social play sessions, and these 92% of the incidents occurred during dolphin-dolphin play sessions.
Dolphins were also more likely to make open-mouthed expressions when their faces were within the field of view of their playmates, with 89% of recorded open-mouthed expressions produced in this situation. When this “smile” was recognized, the playmate smiled back. With a probability of 33%.
“Given that dolphins frequently participate in the same activities and situations, some might argue that dolphins are simply copying each other’s open-mouthed facial expressions by chance, but this This does not explain why the probability of imitating another dolphin’s open-mouth expression within 1 second is 13 times higher if the recipient actually saw the original expression. ” said Dr. Palagi.
“This rate of mimicry in dolphins is consistent with what has been observed in certain carnivores, such as meerkats and sun bears.”
of study Published in a magazine iscience.
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veronica marieri others. Smiling underwater: Exploring the playful signals and rapid imitation of bottlenose dolphins. isciencepublished online October 2, 2024. doi: 10.1016/j.isci.2024.110966
Source: www.sci.news
