Sexual dimorphism shapes the plasma metabolome of the endangered Iberian lynx

Sexual dimorphism is a key but still incompletely resolved determinant of mammalian systemic metabolism, particularly in endangered species where physiological organization remains poorly characterized. Here, we integrate untargeted plasma metabolomics to dissect hierarchical determinants of systemic metabolic organization in the Iberian lynx ( Lynx pardinus ), one of the world’s most endangered felids. We show that plasma metabolic profiles exhibit distinct patterns associated with sex and age class ( n = 37). Sex is the dominant axis of variation, driving coordinated divergence across lipid remodelling, taurine-associated metabolism, fatty acid β-oxidation, amino acid turnover, and endocrine-related pathways. This separation is supported by consistent metabolite-level differences and clear system-level discrimination, indicating widespread metabolic divergence between females and males. Importantly, this sex-dependent architecture persists after sexual maturation and remains stable in adult-only analyses, indicating that the observed structure is not driven by age composition effects. Age shows limited explanatory power and does not yield interpretable systemic structure. Metabolic networks reveal a conserved lipid–taurine backbone, with sex shaping system architecture and metabolic organization persisting despite demographic constraints.