The teeth of sharks are embedded in the gums rather than directly fixed to the jaw, and are constantly replaced throughout the shark's life. Multiple rows of replacement teeth are grown in a groove on the inside of the jaw and moved forward in a "conveyor belt"; some sharks can lose some 30,000 teeth in their lifetime. The rate of tooth replacement varies from once every 8–10 days to several months. In most species teeth are replaced one at a time, while in the cookiecutter sharks the entire row of teeth is replaced simultaneously.
The skeleton of a shark is very different from that of bony fish and terrestrial vertebrates. Sharks and other cartilaginous fish (skates and rays) have skeletons made from cartilage, which is a flexible and dense connective tissue, but they are still considered bones. They function in the same way as human bones do
Normally, sharks eat alone. But sometimes one feeding shark attracts others. They swim up as quickly as possible and all begin to try to get a piece of the prey
Baby sharks are called pups. Just like there are many types of sharks, there are also different ways that sharks come into this world. There are three ways that sharks are born: eggs are laid (like birds)
flat body like a stingray -- you can tell the shark is not a ray because the pectoral fins are not attached to the head. They bury themselves in the sand or mud with only the eyes and part of the top of the body exposed. They are bottom feeders, eating crustaceans like clams and mollusks and fish that are swimming close to the ocean floor
second largest shark (about 30 feet long and 8,000 pounds) filters plankton from the water using "gill rakers