  Interpretation of animal behavior, especially as cooperative or selfish, is a
challenge for evolutionary theory. Strategy of a competition should follow from
corresponding Darwinian payoffs for the available behavioral options. The
payoffs and decision making processes, however, are difficult to observe and
quantify. Here we present a general method for the derivation of evolutionary
payoffs from observable statistics of interactions. The method is applied to
combat of male bowl and doily spiders, to predator inspection by sticklebacks
and to territorial defense by lions, demonstrating animal behavior as a new
type of game theoretical equilibrium. Games animals play may be derived
unequivocally from their observable behavior, the reconstruction, however, can
be subjected to fundamental limitations due to our inability to observe all
information exchange mechanisms (communication).
