Ureotelism - Excretion
Terrestrial animals with restricted water availability in the environment are faced with the formidable task of water conservation. Since they cannot afford to use liberal quantities of water for excretion, ammonia is converted into a less toxic product.
In mammals and semi-terrestrial adult amphibians, the major nitrogenous excretory product is urea, which is less toxic and easily soluble. These animals are therefore called ureotelic.