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White shark





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Flying fish

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Flying fish can be seen jumping out of warm ocean waters worldwide. Their streamlined torpedo shape helps them gather enough underwater speed to break the surface, and their large, wing-like pectoral fins get them airborne.

Flying fish are thought to have evolved this remarkable gliding ability to escape predators, of which they have many. Their pursuers include mackerel, tuna, swordfish, marlin, and other larger fish. For their sustenance, flying fish feed on a variety of foods, including plankton.

There are about 40 known species of flying fish. Beyond their useful pectoral fins, all have unevenly forked tails, with the lower lobe longer than the upper lobe. Many species have enlarged pelvic fins as well and are known as four-winged flying fish.

The process of taking flight, or gliding, begins by gaining great velocity underwater, about 37 miles (60 kilometers) per hour. Angling upward, the four-winged flying fish breaks the surface and begins to taxi by rapidly beating its tail while it is still beneath the surface. It then takes to the air, sometimes reaching heights over 4 feet (1.2 meters) and gliding long distances, up to 655 feet (200 meters). Once it nears the surface again, it can flap its tail and taxi without fully returning to the water. Capable of continuing its flight in such a manner, flying fish have been recorded stretching out their flights with consecutive glides spanning distances up to 1,312 feet (400 meters).

Flying fish are attracted to light, like a number of sea creatures, and fishermen take advantage of this with substantial results. Canoes, filled with enough water to sustain fish, but not enough to allow them to propel themselves out, are affixed with a luring light at night to capture flying fish by the dozens. There is currently no protection status on these animals.

 

The large and extremely aggressive white shark, Carcharodon carcharias, is considered by most experts to be the most dangerous shark in the world. Although the total number of attacks by white sharks on swimmers, surfers, and boats is higher than that by other sharks, the rate of attack is relatively low, certainly much lower than other fatalities on the sea such as drowning.



White sharks are large, reaching a size of at least 6 meters and perhaps as much as 8 meters in length. Large individuals may weigh as much as 2,180 kilograms. The mouth is large and located on the undersurface of the head. Large gill slits, of which there are five on each side of the head, extend onto the upper surface of the body.

The fearsome teeth of the white shark are particularly notable: large, triangular, and bladelike. These teeth, combined with the shark's powerful jaws, size, and swimming strength and speed, make the white shark a superpredator capable of exploiting a variety of prey. Its diet includes fishes and marine mammals. Young white sharks tend to favor fishes, while mature sharks appear to prefer mammals. Other sharks and invertebrates such as crabs and squid also serve as prey. Less commonly found in the stomachs of captured white sharks are sea turtles and birds such as gulls, and penguins. The remains of sheep, pigs, horses, dogs, and, rarely, humans have been found in their stomachs, as has undigestible garbage.

The white shark usually attacks its prey from behind or below, often with a sudden burst of speed. If necessary, the shark may roll over on its back or twist sideways to attack more effectively.

The white shark, like the other members of the same family, owes much of its strength and endurance to adaptations in its circulatory system that enable it to maintain a body temperature above that of the surrounding water. A series of structures called countercurrent exchangers, located near the gills, forms a thermal barrier that prevents the loss of heat from the body into the surrounding environment. The resultant increased body temperature allows for a more efficient metabolism, enabling these sharks to swim faster and with greater strength and endurance than fish that lack this adaptation.

 





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