Animals use a wide variety of strategies to reduce or avoid aggression in
conflicts over resources. These strategies range from sharing resources without
outward signs of conflict to the development of dominance hierarchies, in which
initial fighting is followed by the submission of subordinates. Although models
have been developed to analyze specific strategies for resolving conflicts over
resources, little work has focused on trying to understand why particular
strategies are more likely to arise in certain situations. In this paper, we
use a model based on an iterated Hawk--Dove game to analyze how resource
holding potentials (RHPs) and other factors affect whether sharing, dominance
relationships, or other behaviours are evolutionarily stable. We find through
extensive numerical simulations that sharing is stable only when the cost of
fighting is low and the animals in a contest have similar RHPs, whereas
dominance relationships are stable in most other situations. We also explore
what happens when animals are unable to assess each other's RHPs without
fighting, and we compare a range of strategies for this problem using
simulations. We find (1) that the most successful strategies involve a limited
period of assessment followed by a stable relationship in which fights are
avoided and (2) that the duration of assessment depends both on the costliness
of fighting and on the difference between the animals' RHPs. Along with our
direct work on modeling and simulations, we develop extensive software to
facilitate further testing; it is available at
\url{https://bitbucket.org/CameronLHall/dominancesharingassessmentmatlab/}