Animals feed
Powered flight
Bats are the only living mammals that sustain powered flight, using repeated wingbeats rather than simply gliding. Their wings are flexible membranes supported largely by elongated fingers.
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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.