Policy and population distributions for identical players when there is a disadvantage to foraging together. This figure shows a case where the risk of being predated when foraging alone is lower than that when foraging together – the optimal policy reflects this by ensuring that players are always engaged in alternative behaviours: a) optimal policy, where darkest squares represent 'forage 100% of the time, lightest squares represent 'rest 100% of the time', and intermediate levels of shading represent a continuum between these two. Parameters are as given in table 3, except that c
= 3, m
= 0.00002, m
= 0.00001, m
= 0.00003; b) stable population distribution resulting from policy.