Morphological, Morphometric and Phaneroptic Variations of the Mediterranean Donkey and Tunisian Perspective on Conservation and Breeding

The domestic donkey (Equus asinus) remains an essential component of agricultural systems worldwide, particularly in rural Tunisia. This study aims to conduct a comprehensive morphological characterization of the Tunisian donkey population, focusing on phaneroptic variation, sexual dimorphism and live weight prediction. A total of 556 clinically healthy donkeys, consisting of 207 males and 349 females, were sampled from various governorates in Tunisia. Descriptive statistics revealed significant variability in withers height (98–147 cm), thoracic circumference (100–165 cm) and body length (86–144 cm). Principal Component Analysis identified coat color and belly pigmentation as major contributors to phaneroptic variation, explaining 69.556% of the total variance. Hierarchical Ascendant Classification further classified the population into three distinct groups, with Group I exhibiting smaller body dimensions, Group II having medium sizes, and Group III consisting of larger donkeys. Sexual dimorphism was detected in neck circumference (females: 64.30 cm vs. males: 61.97 cm; FDR-adjusted p = 0.0468). Regression models for predicting live weight indicated that thoracic circumference was the most reliable single predictor (R2 = 95.4%). Overall, the study documents a wide range of morpho-biometric variation within the Tunisian donkey population and provides practical tools for field-based weight estimation, offering valuable insights for future conservation strategies and management programs.