The embryos of tiger sharks fight each other while in their mother's womb. The survivor is the baby shark that is born.
Dolphins sleep at night just below the surface of the water.
They frequently rise to the surface for air. A cockroach can live up to 10 days without a head. An albatross can sleep while it flies. It apparently dozes while cruising at 25 mph. The slave ants build homes for and feed the Amazon ants, who cannot do anything but fight.