Ureotelism involves converting harmful ammonia produced as a byproduct of protein metabolism into less toxic urea for disposal. Unlike ammonotelic animals (like insects and aquatic organisms) that release excess nitrogen directly as ammonia to the environment, ureotelic animals possess more evolved nitrogen metabolism, and the synthesis of urea helps reduce water loss.
Many terrestrial reptiles—including snakes, lizards, turtles, and birds—are representative ureotelic creatures. Their ability to produce and store urea in specialized body compartments has contributed to their adaptations and flourishing in drier regions. Other ureotelic organisms include adult amphibians (during terrestrial life) and several mammals.