Rewiring Their Social Networks

Rewiring their social networks is something that has been going on with bottlenose dolphins in Moreton Bay on the Queensland coast of Australia. This is not due to a recent love fest, but is the result of enlightened self-interest.

 Ansmann et al’s study followed the two groups that coexisted in Moreton Bay steadfastly ignoring each other for years (1, 2). The smaller group kept doing the usual dolphin thing of hunting fish in little flexible sub-groups of the network. But the larger group members were kicking back, taking it easy in a tight network waiting for the shrimp trawlers to give them a free handout of bycatch.

Free lunches don’t last forever and when a ban on trawling was imposed, times had to change. Hunting isa collaborative activity and the two networks are now interacting with intergroup network nodes.

No danger of bycatch looked like good news for the prey fish, but with the networks merging to gain efficiencies of scale in hunting, they will wipe out that gain. I guess it's the usual thing if you are well down the food chain – your screwed if they do and you’re screwed if they don’t.

 It will be interesting to see how the new network develops and see if it grows organically by other dolphins signing up, or whether other smaller networks will drift into range and get subsumed into the growing giant.

  1. I.C. Ansmann et al, J. Animal Behaviour, 2012,                                                  

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