Bottlenose dolphins 'smile' to say it's time to play

Dolphins are among the most playful and social animals on Earth, yet we don't know much about how they communicate during games and other more light interactions. New research of captive bottlenose dolphins (Tursiops truncates) indicates that they use an "open mouth" facial expression similar to a smile to communicate during social play. This expression was most consistently used when a dolphin is in their playmate's field of view and some respond with a similar expression. The findings are detailed in a study published October 2 in the Cell Press journal iScience. For dolphins, play can include acrobatics, surfing, playing with objects, chasing, and playfighting.