Sharks

Dynamics/Shape/Movement

The body of the shark works together as if it is all one. All of the aspects help it in every way. They have narrow, torpedo shaped bodies that enable them to zip through the water. Some scientists call them the "Biological Torpedoes". Their body is long and slender, pointed at the snout and gradually gets thicker near the middle, but comes back at the tail. They use their pectoral fins to lift themselves in the water. Most of their "thrust" comes from their amazingly strong tails (caudal fins). The denticles along with their dorsal fins streamline for the shark. Sharks can't swim backwards for various reasons. First of all, they can't thrust with their snout, and even if they could do that, their gills wouldn't allow it because they are angled backwards. Therefore, the water would not circulate and no oxygen would be separated from the water and reach their lungs. Many sharks would drown if they stopped swimming, but others can lie at the bottom of the sea, pumping water through their gills by opening and closing their mouths. Because of these attributes, sharks are the fastest marine animals alive.