Locomotion
Sharks swim by moving their caudal fin from side to side in a sweeping motion which propels them forward through the water. The large upper lobe of the caudal fin of most sharks provides most of the forward thrust. Sharks, like makos, which sometimes need to swim at high speed, also have a well-developed lower caudal fin lobe for greater thrust. As a shark moves through the water, it angles the pectoral fins to change direction.
Sharks are slightly heavier than water, so they naturally tend to sink. Buoyancy or lift is provided in two ways. First, sharks store large quantities of oil in their liver. Because oil is less dense than water, storing this oil decreases the overall density of the shark
Sharks are slightly heavier than water, so they naturally tend to sink. Buoyancy or lift is provided in two ways. First, sharks store large quantities of oil in their liver. Because oil is less dense than water, storing this oil decreases the overall density of the shark