What Do Sharks Look Like?

Christian Jensen/CC-BY 2.0

There are 465 known species of sharks that display different physical characteristics. Most are identifiable by their darker upper sides that blend with the water above and their white or lighter-colored undersides that blend with the sea below, in addition to their fins, side gill slits and rows of sharp teeth. Shark skeletons are composed of cartilage, a light and flexible tissue.