Vasopressin, a peptide hormone found primarily in mammals, serves various physiological functions, including water reabsorption and vasoconstriction. However, its non-mammalian counterparts, which possess similar functions, often go unnoticed. These synonyms for "Vasopressin Non Mammalian" include equivalents such as "Arginine Vasotocin" or "AVT" in amphibians, reptiles, and birds. Similarly, "Isotocin" or "Mesotocin" serve as non-mammalian substitutes for Vasopressin in fish and birds, respectively, regulating osmoregulation and social behaviors. Understanding these alternatives broadens our knowledge of the intricacies of hormonal systems across different species, highlighting the diversity and adaptability of non-mammalian organisms.