In biology, resource holding potential (RHP) is the ability of an animal to win an all-out fight if one were to take place.The term was coined by Geoff Parker to disambiguate physical fighting ability from the motivation to persevere in a fight (Parker, 1974). Originally the term used was 'Resource Holding Power', but 'Resource Holding Potential' has come to be preferred. The latter emphasis on 'potential' serves as a reminder that the individual with greater RHP does not always prevail. An individual with more RHP may lose a fight if, for example, it is less motivated (has less to gain by winning) than its opponent. Mathematical models of RHP and motivation (aka resource value or V) have traditionally been based on the hawk-dove game (e.g. Hammerstein, 1981) in which subjective resource value is represented by the variable 'V'. In addition to RHP and V, George Barlow (Barlow et al., 1986) proposed that a third variable, which he termed 'daring', played a role in determining fight outcome. Daring (aka aggressiveness) represents an individual's tendency to initiate or escalate a contest independent of the effects of RHP and V.