Consider the bottle-nosed dolphin. Male dolphins, programmed to play win-win games, team up with other male dolphins to form a coalition. The coalition then abducts a female dolphin from a competing coalition, forcibly detaining her and taking turns having sex with her. Coalitions even play non-zero-sum games with other coalitions. Coalition A helps coalition B steal a female from coalition C today, and coalition B returns the favor tomorrow.
This is quite a display of cooperation—cooperation on top of cooperation—and is yet another tribute to natural selection’s genius.
– Robert Wright, Nonzero: The Logic of Human Destiny (1999)