Cooperation often occurs in the most unexpected places. Check out this original research paper — “The structure of a bottlenose dolphin society is coupled to a unique foraging cooperation with artisanal fisherman” — by Fabio Daura-Jorge, Mauricio Cantor, Simon N. Ingram, David Lusseau, and Paulo C. Simões-Lopes. Note: the authors of this excellent report don’t cite Robert Trivers’s classic reciprocal altruism paper, but they should have! (Hat tip to the amazing Tyler Cowen for the pointer.)

 Social network of dolphins