We are not the only ones who smile “with 32 teeth” although the number of teeth is irrelevant. Even animals smile in different situations, and so do dolphins. These very social and intelligent cetaceans, in fact, laugh.
This was revealed by a new scientific study conducted by the universities of Pisa, Turin and Rennes and published in the magazine Cell Press iScience. The research focused on bottlenose dolphins Tursiops truncatus, investigating their “open-mouthed” facial expressions.
By following the behavior of a group of captive specimens, researchers have demonstrated for the first time that bottlenose dolphins they exchange smiles during moments of play. A total of 1288 cases of “open mouth” were recorded over the course of playful interactions.
89% of the observations occurred in this context and 33% of the time the smile was reciprocated.
During our study we not only observed this facial expression, but we also demonstrated that dolphins are able to replicate it, in fact when they see the “laughter” of one of their peers they return it one time in three” explains Professor Elisabetta Palagi of the University of Pisa, who coordinated the international research team.
The expression was used predominantly when the dolphins saw one of their own rather than when they interacted with humans or were alone. The dolphins were likely to laugh with their companions.
The data collected proves that dolphins also use this facial expression to communicate playfulness.
The relaxed open mouth, which is seen in mammals, from carnivores to primates, including humans, is a universal sign of playfulness, which helps players avoid a fighting game from escalating into conflict” continues Dr. Palagi.
In fact, it is believed that this expression may have evolved from the action of biting without there being any contact between the individuals. The behavior has also been observed in other animals such as, for example, bears and mongooses.
As far as dolphins are concerned, it is fascinating to discover new curiosities and practices with communicative intentions, which however do not belong to the field of acoustic communication. The main studies have focused on the latter, investigating the sounds and whistles used by dolphins.
Visual communication brings with it valuable information that can help scientists improve knowledge about this species. However, one has to wonder how visual communication occurs in nature, in a habitat where dolphins are free to express themselves without chains or training.
