These different families of sharks are very different in the way they look, live, and eat. They have different shapes, sizes, color, fins, teeth, habitat, diet, personality, method of reproduction, and other attributes. Sharks belong to the group of cartilagenous fish, the Elasmobranchii, that includes the sharks, rays, and skates . There are over 350 different species of sharks. The spiny dogfish shark is the most common shark.
Sharks are a type of fish that have no bones, only cartilage.
Some parts of their skeleton, like their vertebrae, are calcified. Sharks belong to the group of fishes called Elasmobranchii, which also includes the rays, skates , and ratfish. The Elasmobranchii are all fish that have no bones, only cartilage. Most sharks do not chew their food, but gulp it down whole it in large pieces. Most sharks have about 5 rows of teeth at any time.