Urea is less toxic than the ammonia excreted by ammonotelic organisms. It requires 0.05 L of water to excrete 1 g of nitrogen, approximately only 10% of that required in ammonotelic organisms. Ureotelic organisms include cartilaginous fish, some bony fish, adult amphibians, and mammals, among others. Humans can be described as being ureotelic organisms.
- S. Sreekumar (2010). Basic Physiology. PHI Learning Pvt. Ltd. p. 180–181. ISBN 9788120341074.
- Definition: ureotelic from Online Medical Dictionary