Big-horned sheep.  As John pointed out, however, they aren't very sheep-like.  For instance: no...

Big-horned sheep. As John pointed out, however, they aren't very sheep-like. For instance: no long hair. Maybe it's an adaptation to the heat? We thought they looked more like goats, anyway.

Location
TucsonArizona-Sonora Desert Museum
Photographer
Catherine Hovell
Date taken