Serpents, as highly adaptable vertebrates, provide robust models for studying the mechanisms of dietary specialization. Using an integrative multi-omics approach, encompassing host genomic, transcriptomic, proteomic, gut metagenomic, and enzymatic analyses, the mechanisms underlying dietary adaptations in the Mengla snail-eating snake (Pareas menglaensis), a species specialized in consuming snails is investigated. Adaptations supporting this diet included evolution of infralabial glands secreting toxin homologs and digestive enzymes, facilitating molluscan predation and digestion. This specialization has driven adaptive evolution in the host genome and shaped the gut microbiota, addressing both nutritional challenges (e.g., lipid deficiency) and digestive requirements (e.g., mucus degradation) associated with snail consumption. Notably, the functional convergence in microbial gene functions between reptiles and mammals highlights parallel evolutionary pathways in dietary specialization. These findings elucidate the genomic foundations of dietary specialization in P. menglaensis, offering broader insights into evolutionary adaptation within a holobiome framework.