Yawning bottlenose dolphin = September 2017,

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Yawning bottlenose dolphin = September 2017, “Minamichita Beach Land” in Mihama Town, Aichi Prefecture (provided by Akiko Enozu)

Mie University and others announced on the 13th that they found bottlenose dolphins yawning in the water at the aquarium “Minamichita Beach Land” in Mihama Town, Aichi Prefecture. It is said that it is the first time in the world to observe mammals that live completely underwater. It was published in the electronic version of the international journal of ethology on June 12.

According to the research team, the definition of yawning is “slowly open the mouth to breathe air, and after reaching the maximum size of the mouth, spit out a short amount of air to close the mouth.” Dolphins are yawning in water that cannot breathe and suggest that the definition needs to be changed.

The team found five behaviors in which the mouth was slowly opened, maintained at maximum size, and then closed rapidly.