SHARKS

Sharks are an amazing group of fish, found in all the oceans of the world.They have been around since before the dinosaurs. There are over 400 types of sharks.

Unlike many other fish, sharks don't have bones. Their skeletons are made up of a light, bendy material called cartilage. This allows sharks to move with ease and speed. A shark's skin is tough and feels like sandpaper. It is made up of 'denticles' which are tiny sharp scales that are made of the same material a human teeth.

Sharks have gills for breathing underwater. As they swim along, sharks take in oxygen from the water that passes over their gills. Great White sharks can have up to 30,000 teeth in their lifetime. When they lose a tooth another one moves forward to take its place. All sharks have an excellent sense of smell and most have a very good eyesight.

Sharks balance the ocean ecosystem as they feed on herbivores that eat coral reef. 100 million sharks are killed every year by people. Thankfully there are organizations that are working to protect sharks.