ause the shark is designed for feeding. In link to the teeth is the shark’s olfactory sense, the best in the seas. It is impossible to imagine how sensitive the olfactory nerves are. The great white shark can sniff out one drop of blood miles away. Even if one drop of blood is diluted with billions of gallons of water, a shark can still detect it. This is possible because of fluid filled sacs on both sides of the fish called lamellae, running the entire length. The walls of the tubing are so sensitive that vibrations as far away as eight miles can be felt. The shark contains a lateral line system below the skin of the head and along the sides of the body. The lateral lines contain sensory cells called neuromasts. Any turbulence, current or vibrations stimulate these hairlike structures. It mainly senses low-frequency vibrations. The walls of the tubing are so sensitive that vibrations as far away as eight miles can be felt. The shark has twenty to thirty little black “freckles.” Not only do the freckles pick up the scent of blood, but also electrical fields as tiny as .005 microvolt. Each organism in the creature gives out a small electrical field, and since the water is such a great conductor, this is very advantageous to the shark. Sharks attack bleeding victims, not only because the scent of the blood, but because the blood releases so many ions in the water, intensifying the electrical field. The electrical fields are detected by the Ampullae of Lorenzini. External pores cover the surface of the shark’s head. Each pore connects to a jelly-filled canal leading to the ampullae. The ampullae detect the weak electrical fields at short ranges. The Amupllae of Lorenzini can also detect salinity, magnetic fields, temperature change as well as changes in water pressure, and mechanical stimuli. The shark’s brain is simple; it consists of a forebrain, midbrain, and a hindbrain. The forebrain ...
