Dolphins “smile” during play, scientists find

Dolphins are widely considered the second smartest animal on our planet, next to humans. They have an entire section of their brain dedicated to echolocation, allowing them to understand the area around them in fascinating detail with their use of sound. They have a strong sense of self, capable of recognising themselves in a mirror, and are known to use given names within their pods that they use to identify each other.

One of the most interesting discoveries about intelligence in dolphins is their enjoyment of play. They have been observed to flip and spin about the sea for no observable reason other than enjoyment. In a recent study published by Elsevier Inc, dolphins have been observed to evoke specific facial displays whilst playing that are similar to the way humans smile.

The study focused on playful visual communication in bottlenose dolphins, and it was observed that open mouth (OM) display was evoked during social play, most often when the dolphin’s playmate was in their view. This suggests that dolphins respond to their playmate’s own happiness, as OM display was seen to result in a mirror response from the dolphin’s playmate, described as rapid facial mimicry (RFM).

Bottlenose dolphins are some of the most social mammals, known to live in complex communities made up of large groups containing their own internal subgroups. Dolphins are capable of forming long-term memories of their friends and family, and remember them for up to decades.

The replication rate of OM when the receiver notices the facial display in the other dolphin rises 13 times higher than when they don’t, which seems to suggest that this isn’t pure coincidence.