A Modern Metrical Baseline for Sexing Sheep Horn-Cores

Sex determination is essential for reconstructing past livestock management, yet the limited skeletal sexual dimorphism of sheep hinders the identification of ewes, rams, and wethers in archaeological assemblages. Horn-cores are the most sexually dimorphic element of the sheep skeleton, and here, we establish a new metrical baseline for differentiating these groups. This was created using three measurements—basal circumference, maximum basal diameter, and minimum basal diameter—derived from 117 sheep of known sex (female, male, castrate) and breed (n = 15). Cross-validated analyses demonstrate that approximately 70% of individuals can be correctly assigned using a single measurement, increasing to over 80% when measurements are combined. We apply this new baseline to horn-core assemblages from three archaeological sites in Britain and identify sex profiles consistent with different industries, including dairying, wool production, and craft production. Of particular importance is the ability to positively identify castrates in some cases, and the differentiation of males and females, even in samples of mixed age and breed.