 We set out to better understand the role that vocal communication plays in the coordination of social behaviour like cooperation in bottlenose dolphins. And what we found is that male dolphins that form long-term cooperative partnerships or alliances with one another retain individual vocal labels or names that allow them to track rivals and friends in their social network. It's an unusual finding because across the animal kingdom many animals make their cause more similar when they form strong social bonds. For example we see this in species such as parrots, bats, elephants and primates. However with the bottlenose dolphins it's the opposite. Males retain a unique call even though they form these incredibly strong bonds. By keeping these individual vocal labels males are able to track these relationships at the individual level. They are able to keep track of who their cooperative partners are, who their competitors are and so in this multi-level alliance system they are able to remember the history of relationships and which relationships are important to them. Alliance formation that we see in Shark Bay is actually incredibly rare and it's the only example we have outside of humans where you see alliances within alliances. Another interesting observation from our study was that males use tactile contact as a way of reinforcing their social bonds. They don't share a call, they retain their individual name and so in order to reinforce their bonds they employ tactile contact where they use their pictorial fins to rub against each other similar to holding hands or hugs in human society and so dolphins employ these kind of behaviors in order to advertise alliance unity.