Dolphins in playful moods have been found by scientists to exhibit what looks like smiling behaviour. The researchers have observed bottlenose dolphins engaging in underwater acrobatics, playing with objects, and chasing each other, with a particular expression resembling a smile.
According to the study, these dolphins use an “open mouth” expression during play to communicate with each other, much like a smile in humans. Interestingly, when these dolphins ‘smile’ at their playmates, they receive a similar response approximately 33% of the time.
Dr. Elisabetta Palagi, an evolutionary biologist from the University of Pisa, shared, “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.”
The study highlights the role of visual communication in shaping complex social interactions not only in dolphins but in many species over time. It suggests that the open-mouth signals and rapid mimicry seen in dolphins have played a crucial role in their social behaviour.
These findings are particularly fascinating as they shed light on the playful nature of bottlenose dolphins, which are known to be highly social animals often found in small groups of up to 15. In the UK, prime locations to witness these creatures include the Moray Firth in Scotland, Cardigan Bay in mid-Wales, and the coasts of Cornwall, Northumberland, and North Wales.
Apart from humans, other species such as chimpanzees have been observed using facial expressions to communicate playfulness, and this study raises questions about whether marine animals exhibit similar behaviour. The research involved observing 22 captive bottlenose dolphins during play sessions, both with each other and with human trainers.
The results showed that dolphins used the open mouth expression predominantly when engaging in play with other dolphins, not with humans or when alone. The study recorded 1,288 open mouth events during social play sessions, with 92% occurring during dolphin-dolphin play sessions.
These playful expressions were more likely to occur when the dolphins’ faces were visible to their playmates, indicating a form of intentional communication. Dr. Palagi noted, “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.”
The study, published in the journal iScience, emphasises the significance of visual cues in understanding social interactions among dolphins and other species. It provides valuable insights into the intricate communication systems that exist within the animal kingdom.