Dolphin Gangs

While we flock to watch dolphins do tricks in large aquariums, we recognize that they are intelligent mammals that are used to wandering freely around the oceans. They travel long distances and don’t stake out small territories.

Connor et al have been studying bottlenose dolphins around Shark Bay for quite some time now and will have their latest report in Proc. Roy. Soc. B and Gill has given us a pre-publication summary in BBC Nature (1).

The dolphin groups wander about the ocean in a well-organized society. Males form alliances of different types to organize their females. At the ‘local’ level two or three males get together to herd their females, but they form larger gangs with up to a dozen or fourteen gang members to go raiding other dolphin troupes to steal their females.

All this is good fun if you are a young male dolphin, but of course they can sometimes meet stiff opposition and then the dolphin gangs forget about looking after what they’ve got. They band together into a little army to take on the opposition.

Apparently though, when they meet another group they don’t always want to fight, as would be the case if it were territory that they were defending. As it’s their females that they are worried about, if there is no obvious threat, they play nice.

In some cases, playing nice can mean groups joining up or having some small groups of males going off with the new group. So it appears that they have a complex social network with a variety of alliances. Only humans come close to having such hierarchical alliances according to the authors of the study, although the herding and stealing of females from other gangs makes me worry a bit about the comparison.


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