Sharks, together with rays and skates, make up the subclass Ela.... shark fish,

All other sharks prey on small sharks, fish, squid, octopuses, shellfish, and, in some species, trash. The largest among them is the voracious 6-metre (20-foot) great white shark, or man-eater, which attacks seals, sea turtles, large fish, and occasionally people. The more sluggish ( Somniosus ) of cold, deep waters, while half the size of the white shark, reputedly feeds on seals, large fish, whales, and even swimming reindeer. Normally, sharks feed on fish, often attacking in schools; open-ocean species such as the , , and sharks frequently feed near the surface and are much sought-after by rod-and-reel sportsmen. The origin of sharks is obscure, but their geologic record goes back to the Devonian Period (408 to 360 million years ago). Modern sharks appeared in the Early Jurassic Period (208 to 187 million years ago) and by the Cretaceous Period (144 to 66.4 million years ago) had expanded into present-day families. shark fish,