Behavior of captive mountain sheep in a Mojave desert environment

We studied group dynamics, activity, and foraging related to social rank of Nelson's mountain sheep (Ovis canadensis nelsoni) in a 3.2 km(2) enclosure at the Desert National Wildlife Refuge, Nevada. Sheep in the enclosure exh ibited grouping patterns similar to free-ranging populations, with group si ze and structure changing seasonally. Solitary sheep spent more time moving than did sheep in groups of greater than or equal to 2. Social structure o f the enclosed population was significantly hierarchical, but not linear. F emales are more egalitarian, yet have a significant hierarchical social str ucture. Dominant individuals were involved in more interactions than subord inates over the year, and foraged less while bedding more in spring. Subord inates consumed significantly more forbs in winter than dominants. Subordin ates foraged in areas with more grass in spring, and more forbs in winter t han dominants. Higher ranking males had increased access to estrous females , whereas female rank had no correlation to reproductive success or offspri ng survival. Differences between dominant and subordinate sheep in foraging site characteristics, forage intake, or percent time spent foraging are pr obably sex-specific and unrelated to social status. Social rank appears to be tied to the reproductive success of males, but not females.