Great White Shark
Scientific namee:Carcharodon
As a group, sharks are adapted for a wide range of aquatic habitats. Various species inhabit shallow coastal habitats, deep-water ocean floor habitats,and the open ocean
As a group, sharks and batoids eat almost anything: fishes, crustaceans, mollusks, marine mammals, and other sharks.
While some sharks are probably not very selective feeders, certain sharks eat some foods more than others. For example, hammerhead sharks (Sphyrna spp.) are known for eating stingrays; bull sharks (Carcharhinus leucas) eat other sharks; and smooth dogfish (Mustelus spp.) eat crabs and lobsters.
Recordings of the movements of tagged sharks suggest that most sharks undergo daily activity rhythms. Their greatest activity occurs during the twilight and dark hours.
Pilotfish (usually Naucrates ductor, but there are others) often travel with sharks, for unclear reasons. This relationship may be due to the natural schooling behavior of pilottish, or the pilotfish may conserve energy by riding the hydrodynamic bow wake of the shark. Pilotfish also eat small amounts of food scraps released as the shark feeds.
Few people have witnessed the mating activity of sharks.
In smaller, more flexible species the male coils around the female.
In larger, more rigid species the male orients himself parallel and head-to-head with the female.
During mating, males of many species bite females on the pectoral fins or the middle of the back to hold onto them. Females often bear scars or marks. Upon examination, these marks show they have been made by upper jaw teeth. In some elasmobranchs, males have longer, narrower teeth than females. In some female sharks, such as the blue shark (Prionace glauca), the skin on the back and flanks is more than twice as thick as the skin on the males.
Hearing.
Sharks have only an inner ear, which consists of three chambers and an ear stone called an otolith. A shark's inner ear detects sound, acceleration, and gravity.
Sharks use sound to locate food.
Sound is often the first sense a shark relies on to detect prey.
Under water, sound travels faster and farther than on land.
sharks are attracted to low-frequency pulsed sounds, similar to those wounded or ill prey would emit. Most attractive sounds are in the frequency of 25 to 100 Hz. Some sharks are attracted to sound sources from distances as great as 250 m (820 ft.).
Lateral line.
The lateral line system is a series of fluid-filled canals just below the skin of the head and along the sides of the body. The canal is open to the surrounding water through tiny pores.
The lateral line canals contain a number of sensory cells called neuromasts. Tiny hairlike structures on the neuromasts project out into the canal. Water movement created by turbulence, currents, or vibrations displaces these hairlike projections and stimulates the neuromasts. This stimulation triggers a nerve impulse to the brain.
Like the ear, the lateral line senses low-frequency vibrations. It functions mainly in distance perception and detecting low-frequency vibrations and directional water flow.
The lateral line system is a series of fluid-filled canals. It senses low-frequency vibrations.
Sharks and batoids show great diversity in size.
1 . The largest of the sharks is the 13.7-m (45-ft.) whale shark (Rhincodon typus).
2. Among the smallest sharks are the 22- to 25-cm (8- to 1 0-in.) midwater shark (Squaliolus laticaudus) and pygmy ribbontail catshark (Eridacnis radcliffei).
3. The largest batoid is the manta ray (Manta birostris), which reaches widths over 6.7 m (22 ft.)
Resources:
Jaws.mid- www.jaws.com
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