Final answer:
The head-butting behavior of male bighorn sheep to establish a mating hierarchy is an example of agonistic behavior.
Step-by-step explanation:
The head-butting behavior of male bighorn sheep to establish a mating hierarchy is an example of agonistic behavior. Agonistic behavior refers to behaviors involved in contests over resources, territory, or mates. In this case, the males are engaging in head-butting to establish dominance and gain access to females for mating.