FISH FACTS - PERPETUAL MOTION

Did you know a charging shark cannot stop. It can swerve but it can't swim in reverse. If it stops beating its tail it sinks.

Rays and skates, which have skeletons made of cartilage the same as sharks, have given up on the energy consuming task of constantly beating their tails. They have become bottom, dwellers. Their tails have become thin and whip like and some have developed poisonous barbs on the end