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In biology, resource holding potential (RHP) is the ability of an animal to win an all-out fight against an opponent, assuming they both adopt the same behavioural strategy.

It is usually related to the animals escalated fighting ability which reflects its comparative size, weight etc.

The term was coined by Geoff Parker to disambiguate physical fighting ability from the motivation to persevere in a fight (Parker, 1974[1]). Originally the term used was resource holding power and also relative 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 it's 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)[2] in which subjective resource value is represented by the variable 'V'. In addition to RHP and V, George Barlow (Barlow et al, 1986[3]) 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.

## Examples of the term in use

• "[...] RHP is a measure of the absolute fighting ability of the individual" (Parker, 1974)[1].
• "Assuming the RHP of the combatants to be equal, there are many instances of fitness pay-off imbalances between holder and attacker which should weight the dispute outcome in favour of one or other opponent by allowing it a greater expendable fitness budget. Usually the weighting favours the holder; the attacker therefore needs a correspondingly higher RHP before it may be expected to win." (Parker, 1974)[1].
• "Each combatant assesses relative RHP; this correlates with an absolute probability of winning the next bout ()." (Parker, 1974)[1].
• "The essential point is to distinguish two cases (i) information about `motivation' or `intentions' [...] (ii) information about `Resource Holding Power', or RHP (Parker, 1974b); RHP is a measure of the size, strength, weapons, etc. which would enable an animal to win an escalated contest" (Maynard Smith 1982[4]).
• "In practise, however, the two opponents are rarely equal in fighting ability, or resource holding potential" (Bradbury & Vehrencamp, 1998[5]).
• "Motivational and physical components are assumed to be separable. [...] The motivation depends upon V, the value of the resource, and the perceived prowess and motivation of the opponent. [...] but there is an additional component. It is the readiness of the individual to risk an encounter, to dare to escalate, measured when the contest is otherwise symmetrical. It differs from V in that daring appears to be an inherent property of the individual rather than a variable motivational state that is tuned to the value of the resource" (Barlow et al. 1986)[3].

## References

1. Parker, GA. (1974) Assessment strategy and the evolution of animal conflicts. Journal of theoretical Biology 47, 223-243 Cite error: Invalid `<ref>` tag; name "Parker74" defined multiple times with different content Cite error: Invalid `<ref>` tag; name "Parker74" defined multiple times with different content Cite error: Invalid `<ref>` tag; name "Parker74" defined multiple times with different content
2. Hammerstein, P. (1981). The role of asymmetries in animal contests. Animal Behaviour 29, 193-205.
3. Barlow, GW., Rogers, W., Fraley, N. (1986). Do Midas cichlids win through prowess or daring? It depends. Behavioral Ecology and Sociobiology 19, 1-8. Cite error: Invalid `<ref>` tag; name "Barlow_etal86" defined multiple times with different content
4. Bradbury, JW. & Vehrencamp, SL. (1998). Principles of animal communication Sinauer, Sunderland, MA.