Contributed by Marielle Grenade-Willis
We are well aware that cetaceans have an amazing array of capabilities such as the use of vocalization and echolocation to socialize and forage. Apparently, these sounds are even more varied and nuanced than we initially realized as studies have now found that dolphins who aid Brazilian fishermen, by corralling fish closer to the shore, actually make different sounds than the dolphins not engaged in this activity but within the same population. “The frequencies of use of the whistle types are dependent of the foraging tactic and social communities; notably, ascending whistles were more frequent than expected in the non-cooperative context, while concave, multiple and flat whistles were more frequent than expected for the cooperative dolphins. Moreover, dolphin members of different social communities emit whistles that differ in some acoustic features. The social community that routinely engage in the cooperative foraging typically emit shorter whistles with a higher frequency and more inflection points than the community of dolphins that only forage independently. These findings illustrate how social sounds can differ between subsets of individuals within the same population and suggest that dolphins may use slightly different whistles according to the behavioural context.” This study exemplifies the unique communicative capacity of these nonhuman animals and the range of their affiliation capability.