i know HT is for science and not so much biology but anyway. some animals iirc don't pee. the water gets recycled and the waste just gets added to the poop. did we just never have a need to evolve this due to having plenty of water around normally or what? europeans may not have had a need but what about people in desert climates? (living in the sahara, aussie aboriginies etc) not much water there so shouldn't an ability like this have evolved there at some point?