Different animals get rid of nitrogenous waste in various ways depending on their habitat and water availability. The three main modes are ammonotelic, ureotelic, and uricotelic excretion.

Key Points to Know

• Ammonotelic: Excrete ammonia directly (very toxic but water-soluble). Found in aquatic animals like fish and amphibian larvae.
• Ureotelic: Excrete urea, which is less toxic and needs less water - seen in humans, frogs, and some mammals.
• Uricotelic: Excrete uric acid, which is almost solid and water-saving - found in birds, insects, and reptiles.