For humans, displaying a smile is an easy way to avoid misunderstandings . And, according to a new study, bottlenose dolphins may use a similar tactic while playing with each other.
The study, published last Wednesday (2) in iScience magazinediscovered that dolphins make an open-mouthed expression, comparable to a “smile”, during their games.
To conduct the research, a group of scientists from institutions in Italy and France observed 11 dolphins at Zoomarine Roma and another 11 at Planète Sauvage in western France, playing with each other, with their human trainers and alone.
The researchers found that the marine mammals almost always “smiled” when they were in the field of vision of their playmates, and the other “smiled” back a third of the time. This suggests that this may be a form of communication. They hypothesized that by “smiling” at each other, dolphins could prevent their games from turning into real fights due to misunderstandings.
However, although the expression resembles a smile to humans, dolphin communication expert Heather Hill, a professor of psychology at St. Mary’s University in San Antonio, Texas, who was not involved in the study, warns against jumping to conclusions. .
“I truly believe that dolphins use the open-mouth response in play situations, and it seems reasonable that it is a form of communication. I don’t feel comfortable calling it a smile because they also use the open-mouth expression in many other contexts,” she told CNN pointing out its use in aggressive, solitary and playful acts.
“We should interpret this as an exchange of open mouths between two individuals to communicate ‘hey, we’re on the same wavelength,’” he added. “Does this necessarily mean that because it is play, it is pleasurable and therefore you and I are smiling at each other, as a human or chimpanzee would? I don’t know if I’m ready to take that next step.”
Much loved — and anthropomorphized — by humans, dolphins are known for their playfulness, rich social lives and complex communication with each other. They have many different ways to play together, such as jumping, jumping out of the water, spinning above the surface, slapping the water with their flippers, play fighting or riding the waves.
But despite dolphins’ playful reputation, their facial expressions during play have never been investigated before, although studies have established that other mammals, such as humans and monkeys, communicate with open, smile-like expressions when playing. Scientists widely believe this behavior stems from a modified biting action without actual contact, according to the study.
Researchers in the latest study found that 92% of the occasions in which dolphins used the open-mouth expression occurred when they were playing with each other, rather than with humans or alone.
When the dolphins were engaged in an aggressive interaction or a more relaxing activity, such as swimming parallel or upside down, scientists did not observe the “smiling” expression.
The researchers also noted the importance of dolphins’ vocal communication during play and stated that this could be a focus for future studies, as they did not record these signals.
“Dolphins have evolved one of the most intricate vocal systems in the animal world, but sound can also expose them to predators or hidden listeners,” said study co-author Livio Favaro, a zoologist at the University of Turin, in a statement.
“When these mammals play together, a mix of whistles and visual cues helps them cooperate and achieve goals, a particularly useful strategy during social play when they are less aware of predators,” he added.
All dolphins observed for this study are living in captivity. Hill noted that “smiling” behavior likely occurs in the wild as well, but perhaps less frequently as they spend more time searching for food and avoiding predators.
“The next step would be to apply the same methodology… work with these wild species and observe what they are doing in the same types of contexts,” she said.
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This content was originally published in Dolphins can use smiles to avoid fights and misunderstandings, says study on the CNN Brasil website.
Source: CNN Brasil
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