Sharks do not have to continually move to survive. They can comfortably lay at the bottom of the ocean. Sharks don't have a swim bladder like other fish, so when they stop swimming, they sink to the bottom. Another big myth is that there are no fresh water sharks. One of the most famous sites of fresh water sharks is a lake in Nicaragua.
Sharks have relatively large brains, and can be compared to relatively advanced animals.
It's hard to believe, but a shark can actually be trained. They have also demonstrated a learning rate of the white rat or pigeon. Sharks have been around for millions of years, and some ancient species have existed before dinosaurs. The first sharks appeared 400 million years ago. They have evolved from placoderms, a group of primitive jawed fishes.