Every behaviourally responsive animal (including us) make decisions. These can be simple behavioural decisions such aswhere to feed, what to feed, how long to feed, decisions related to finding, choosing and competing for mates, or simply maintaining ones territory. All these are conflict situations between competing individuals, hence can be best understood using a game theory approach. Using some examples of classical games, we show how evolutionary game theory can help understand behavioural decisions of animals. Game theory (along with its cousin, optimality theory) continues to providea strong conceptual and theoretical framework to ecologists for understanding the mechanisms by which species coexist.