鲨鱼

Predatory fish characterized by highly developed jaws and a diet that includes living animal prey.

Carnivores or omnivores — they get their food by eating other animals, including smaller fish, cephalopods and crustaceans.

Oxygen breathing — they require dissolved oxygen in the seawater.

Large livers — for buoyancy control and processing a toxin-rich diet.

Earth analog: sharks (selachians). Largely extinct.