Their skeletons are made up completely of cartilage, no bones. This gives them flexibility and makes them lighter. There are more than 350 species of sharks in the world, but most are harmless to humans. More than half of all the species are less than three feet in length. Southern stingrays are cousins of sharks, they look like flattened sharks that have adapted to ocean life in a different way.
Rays use their fins like modified wings to glide through the water and along the ocean bottom.
They also use their wings to dislodge crustaceans and mussels from the sandy ocean floor and eat them. Sand Tiger Shark Turtles and Rays Other Fish Minnesota Zoo Back to the Shark Cam Copyright 2000 by Channel 4000 . All rights reserved. This material may not be published, broadcast, rewritten or redistributed.