Thirteen male dolphins were observed as they swam in a shallow lagoon. Tabulations were made of who was swimming with whom. The table shows the observed frequencies.
R. C. Connor, R. A. Smolker and A. F. Richards, 1992, "Dolphin alliances and coalitions," in Coalitions and Alliances in Humans and Other Animals (Eds: A. H. Harcourt and F. B. M. deWaal). Oxford: Oxford University Press, 415-444.