Our skeletons are made of soft bones called cartilage, which make us very flexible. Cartilage is rubbery material, found in your outer ear and your nose. Our skin feels rough when you touch it, although it looks smooth. That is because it is made up of tiny sharp things called denticles, which stick out of our skin..

Most of us have five different fins. First, we have a pair of side fins called pectoral fins. These lift us as we swim. Second, we have a pair of pelvic fins which are at the bottom of our body and they make our movement more steady and stable. Third, we have one or two dorsal fins which are on the top side of our body and they also help us to move steadily and straight. We also have a single fin near the bottom of our tail, although some of us do not have this. Last, we have a fin on our tail called the caudal fin, which we swing to make us move just like you move your legs when you go swimming.

Sharks do not have gills like fish do but gill slits (between five to seven of them) which look like short black lines near the mouth. These help us to breathe from the water like other fish.

So that we don't drown, we have an oil filled liver, which keeps us floating. We also stay afloat by the way we swim. We do this by holding our side fins as far away from our body as possible and push ourselves forward by flipping and swinging our tail from side to side. This produces a rush of water over the fins, causing us to lift up like a plane lifts when air flows over its wings. Oh and by the way, because of the way we swim, we can only move in a forward direction. We can't swim backwards like you do.

We usually have big mouths and rows of teeth and that is why some of you might be scared of us. Most of us do not chew our food, but gulp it down whole in large pieces. Our teeth are not able to chew food, but only to tear it into mouth-sized pieces.