Scientists have recently discovered that dolphins use a special expression, which looks like a smile, to show they are playing and having fun.
Elisabetta Palagi, a scientist from the University of Pisa in Italy, led a team that watched 22 bottlenose dolphins (a common type of dolphin) playing in captivity. Over several months, they recorded nearly 900 play sessions and saw about 1,300 instances of this "smile."
Dolphins "Smile" Most When Playing with Others, Just Like Humans
The researchers noticed that dolphins used this open-mouth expression most often when they were playing with other dolphins, not when they were playing alone.
About 90% of such "smiles" reportedly happened when the dolphins could see each other. Interestingly, if one dolphin smiled at another, the second dolphin would typically smile back. In many cases, this happened in less than a second, which is similar to how humans often respond with a smile when they see someone else smile.
This could mean that dolphins, like humans, use smiling to bond with others and show that they're being friendly. Palagi believes this "smile" is a sophisticated way dolphins communicate with each other, especially during playful moments, according to Science News.
She says it might even be similar to the way humans smile to show they're happy or want to play. However, it's hard to know if dolphins use this smile the same way humans do.
Palagi is confident that the open-mouth gesture is mostly connected to play. Her team found that during aggressive moments between dolphins, the animals did not show this "smile."
When engaging in aggressive interactions, the dolphins would open their mouths briefly before biting or trying to bite. This suggests that the smile-like gesture is used mainly during friendly, playful times.
Palagi and her team also think that when dolphins smile at each other during play, it might help them keep playing for longer, much like when humans laugh together, it often encourages them to continue having fun.
Experts Caution Against Calling Dolphin Expressions a "Smile" Too Soon
Some other experts, like Erin Frick, a dolphin behavior expert from Eckerd College in Florida, think that the dolphin's open-mouth gesture doesn't always mean they're playing.
Dolphins also open their mouths when they are being aggressive, like when they're trying to scare another animal. Frick said, "I think the open mouth can mean different things in different situations."
Another expert, Heather Hill, a psychologist from St. Mary's University in Texas, agrees that we need to be careful about calling the dolphin's open-mouth gesture a "smile."
Dolphins and whales often open their mouths in different social situations, like when they're playing or when they're not getting along. "I don't think we should call it a smile just yet," Hill said, suggesting that the gesture might mean more than just playfulness.
The researchers hope to study this behavior more in the future to understand if dolphins' smiles are used to show their feelings or if it's simply a way to communicate that they're playing.
For now, this study shows that dolphins have complex ways of communicating and that their "smiles" may be more than just a cute look-they might be key to how these intelligent animals interact with each other.
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