Physical Characteristics and Horn Development

Since 2000, the wealth of information about the physical characteristics and horn growth of mountain sheep (bighorn [ Ovis canadensis ], thinhorn [ Ovis dalli ]) has grown in depth and breadth. We reviewed the literature to update information useful to biologists in the management and conservation of mountain sheep. The growth and size of horns and bodies in mountain sheep result from a complex interplay of multiple factors, including age, genetics, and nutrition. Although all three pieces influence the size, conformation, and growth of horns and bodies in mountain sheep, nutrition, which can act through multiple pathways, often is one of the most influential pieces underpinning the phenotypic expression of mountain sheep. Moreover, nutrition is one of the pieces that managers may be able to influence through conservation and management actions. Understanding the factors that influence body and horn size can contribute to management decisions regarding how factors like harvest practices, disease management, and habitat management interact to affect growth of individuals and population dynamics.