Lineal Discrimination of Horses and Mules. A Sympatric Case from Arauca, Colombia.
Authors: Salamanca-Carreño Arcesio, Jordana Jordi, Crosby-Granados Rene Alejandro, Bentez-Molano Jannet, Parés-Casanova Pere M
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary Researchers from Colombia conducted the first morphological comparison between local horses and mules, examining 150 horses and 15 mules using 24 standardised body measurements to establish species-specific conformation profiles. Five traits emerged as particularly discriminative: heart girth circumference, body length, withers height, croup height, and dock height, which the team incorporated into a linear discrimination formula (X = BL × 0.402 + WH × 0.323 + CrH × 0.352 + DoH × 0.384) capable of reliably separating the two species through osteological analysis. Values above 184.5 indicated a horse skeleton with 100% certainty, whilst values below 174.0 indicated a mule, though the intermediate range (174.0–184.5) showed reduced accuracy (84.4% for horses, 71.4% for mules). Whilst the study's primary archaeological significance lies in differentiating skeletal remains from historical populations, the findings have practical applications for equine professionals assessing conformation; the identified measurements—particularly those relating to depth and length ratios—reflect fundamental structural differences that influence biomechanical function and may inform breeding decisions or individual performance potential. These morphological distinctions, grounded in a defined regional population, provide a quantifiable framework for understanding the conformation divergence between equine species that share similar environmental and management contexts.
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Practical Takeaways
- •When working with skeletal remains or archaeological material from regions where horses and mules coexisted, specific postcranial measurements can reliably distinguish the two species
- •Body length, withers height, croup height, and dock height are the most useful morphological traits for species differentiation in living animals or skeletons
- •The discrimination formula provides a quantitative, objective tool for equid species identification without requiring expertise in complex skeletal anatomy
Key Findings
- •Heart girth circumference, body length, withers height, croup height, and dock height showed statistically significant differences between horses and mules
- •A discriminant formula (X = BL×0.402 + WH×0.323 + CrH×0.352 + DoH×0.384) achieved 100% specificity with values >184.5 for horses and <174.0 for mules
- •The formula demonstrated 84.4% sensitivity for horses and 71.4% for mules in the intermediate range (174.0-184.5)
- •Postcranial skeletal measurements can reliably differentiate horses from mules in sympatric populations, with application to archaeological bone identification