In March 2012 the New Scientist reported on research in Shark Bay Western Australia which shows that male bottlenose dolphins in this area cooperate in groups of two or three. These smaller groups also link with others to form ‘gangs’ of up to 14 males and these ‘gangs’ can sometimes also coalesce to form even larger groupings.
With some exceptions, terrestrial mammals tend to live in more closed social groupings that occasionally accept new members emigrating in from other coalitions. What is curious about this research is that usually such complex alliances are believed to enable males to control particular territory or mates. However, Richard Connor and colleagues tracked 120 male bottlenose dolphins and found no evidence that these groups were formed for these reasons. Connor concludes that these findings suggest that the social networks of these dolphins is ‘unusually open’ and may be related to the relatively low energy costs associated with travel for these dolphins.
The abstract for the original research can be downloaded here.