No seriously. Any scientists/biologist here to help? Even evolutionary wise it seems to be a grey hole; it has no living close relatives and very few fossilised ones. It is an honest to God enigma. A cool looking one, but still. -blam!- it, it might as well have been a chimera. Just stick a beaver, a duck, an otter and a snake in a blender and you got yourself a waddling/paddling mess.