Ornithorhynchus Anatinus
(Platypus)
The platypus is a unique, semi-aquatic mammal that lays eggs that is found in Eastern Australia. The excretory system of the platypus mainly uses the bladder and ureters to excrete waste. These two organs enter into urinogenital sinus, which is connected to the cloaca. The platypus is a monotreme, meaning that it is a mammal that has only “one opening” for mating, laying eggs, and getting rid of waste. This is something extremely rare in mammals. Like most mammals, however, the kidney is extremely important in the excretion of waste from and regulation within the platypus.