||It has been suggested that this article be merged into Metabolic waste. (Discuss) Proposed since November 2016.|
A uricotelic organism is one whose main way to excrete excess nitrogen is by uric acid or its salts. Among the three major forms of excretion of nitrogenous waste in organisms (uricotelism, ammonotelism, and ureotelism), uric acid is the least toxic and the least soluble in water. It can be stored in cells and body tissues without toxic effects and requires only a tiny amount of water, about 0.001 L, per 1 g of nitrogen. A single molecule of uric acid can also remove four atoms of nitrogen, making it more efficient than ammonotelism and ureotelism.
Uricotelic organisms typically have white pasty excreta. Uricotelic organisms include terrestrial arthropods (including insects), lizards, snakes, and birds. Various mammals, including humans, excrete uric acid (for example, the normal output of uric acid in human urine is around 140 to 430 µmol/L), but mammals are classified as ureotelic because urea is their main way of excreting nitrogen.