Animals feed
Electroreception
A platypus uses receptors in its soft bill to detect weak electrical signals from living prey. Combined with touch and movement information, this sense helps it forage underwater without relying on sight.
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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.