The classical, monomorphic, evolutionary games analyze competition among phenotypes while implicitly assuming monomorphic transmission of phenotypic attributes to successive generations. The recently formulated polymorphic evolutionary game theory (PEGT), which adds the underlying genetics and sexual reproduction to evolutionary games, has the potential to revolutionize game theoretical modeling of co-evolutionary processes. In this paper, I apply PEGT methods to the analysis of animal conflicts the oldest, and one of the best-developed areas of evolutionary game modeling. Overall, the polymorphic results are consistent with the sequential assessment hypothesis. However, beyond the specific, the results indicate the need for a degree of caution applied to the existing evolutionary stability results as the polymorphic analysis shows that monomorphic ESS can be destabilized by sexual recombination. Finally, due to the novelty of the analytical approach, I make a particular emphasis on methodology: in particular, demonstrating how to combine generation of pertinent phenotypes with genetic plausibility considerations in the design of PEGT models. (C) 2018 Elsevier Ltd. All rights reserved.