Animals feed
Eggs
The platypus lays eggs, but it is still a mammal. Its young hatch and then feed on milk produced by their mother. This combination belongs to the monotremes, the living mammalian lineage represented by platypuses and echidnas, rather than to birds or reptiles.
3
Octopuses have three hearts: two supply the gills and one supplies the rest of the body. Their oxygen-carrying protein contains copper and turns blue when oxygenated.
Cubes
Wombats produce distinctly cube-like droppings, shaped inside the intestine rather than by a square opening. Research links the shape to differences in the mechanical properties of the intestinal wall.