Dolphins have a reputation as the smiley diplomats of the sea, often depicted as happy, hyper-intelligent friends to man in feel-good films and more. In truth, dolphins are extremely smart and often do react in diplomatic clicks and whistles when face with adversity. Now, the BBC reports that new evidence shows dolphins are adept at not just speaking with their own pods, but also with distantly-related cousins.

University of Puerto Rico biologist Laura May-Collado made this discovery while studying the dolphins of the Costa Rica's Gandoca-Manzanillo Wildlife Refuge. The refuge is home to bottlenose and Guyana dolphins, and May-Collado noticed that they two distant species often interacted. It seems that the two species of dolphins – both which utilize their own distinct language – pick an intermediary language they can both understand when they meet up.

As May-Collado told the BBC, "I was surprised by these findings, as I was expecting both species to emphasize, perhaps exaggerate, their species-specific signals. Instead, the signals recorded during these encounters became more homogenous. This was a very exciting discovery." At present, it is still unclear if one species is changing its signals for the other, or if both species are attempting to communicate with each other.

Further, it is unclear exactly who is saying. As May-Collado points out, dolphins are already known to change their language when they talk to each other. According to May-Collado, "I wouldn't be surprised that they can modify their signals to mimic, and even possibly communicate with other species. Particularly when their home ranges force them to interact on a daily basis, which is the case of this study."

But some point out that this scenario may not necessarily be one of friendly interaction or diplomacy. Bottlenose dolphins are significantly bigger than their Guyana cousins and have been known to bully the smaller species. Dr. May-Collado points out that the Guyana dolphins could even been emitting distress calls in an effort to get the Bottlenose dolphins to back off.

All dolphins are known to communicate through squeaks, whistles, blowing, and slapping the sea with their bodies. Bottlenose dolphin pods usually consist of 10 to 30 members. Some pods have been known to even include a thousand dolphins. They are a formidable presence in the sea and can measure up to 3.8m long. The Guyana dolphins essentially looks like a smaller Bottlenose, measuring around measuring 2.1m long.

For further reading:

Dolphins speak a common language with each other
New evidence shows even distantly-related species will moderate their communications when speaking with each other.