GREAT+WHITE+SHARKS

Recent research on interactions between great whites and various species of seals and sea lions suggests that great whites hunt their prey visually. Using their dark dorsal colors to help them blend in while cruising near rocky bottoms, they watch for unsuspecting seals on the surface above. When an animal is sighted, they accelerate quickly to the surface and ram into their prey, simultaneously stunning it and taking a large bite. They then return to feed on the carcass. Great white sharks have one of the widest geographic ranges of any marine animal. They are found in all cold temperate and tropical waters, from 60°N latitude to 60°S latitude. They were long thought to be primarily coastal inhabitants; however, from recent satellite tracking studies we now know that they migrate long distances, sometimes crossing entire ocean basins. Along the central California coast, they can be found hunting near elephant seal haul-out areas from October through March. Off the western cape of South Africa, they can be found near cape fur seal haul-outs from May to September. In North American waters, white sharks have been reported from Newfoundland to Florida, and from from the Aleutian Islands, Alaska to southern Mexico. Nowhere in its range is the white shark very common, and in fact, they are becoming increasingly rare. The great white shark, //Carcharodon carcharias// (Linnaeus, 1758), aka white shark, white pointer, blue pointer, man-eater, manila shark, has, according to E.O. Wilson "...rightfully been called a top carnivore, a killing machine, the last free predator of man—the most frightening animal on earth." While this is a common perception of white sharks, some courageous explorers have not only free-dived with these "killing-machines," they lived to talk about it. Not that diving with white sharks is recommended, but these bold experiments have shown that these majestic, yet intimidating, creatures are not predators of men. The great white shark is the largest known predatory //fish// in the sea. They reach lengths of over 6.1 m long and weigh up to 2,268 kg. They have a conical snout, pitch black eyes, a heavy, torpedo-shaped body, and a crescent-shaped, nearly equal-lobed tail fin that is supported on each side by a keel. The great white swims in a stiff-bodied, tuna-like fashion, unlike the sinuous whole-bodied swimming stroke of most sharks.

The name "white shark" is thought to have come from its universal all-white belly. The dorsal coloring of great white sharks, however, ranges from pale to dark gray and can vary tremendously depending on lighting and water color and visibility.

The great white's average length is around 3.6 m, but there have been reports of sharks as large as 7.62 m. The great white belongs to the Family Lamnidae (the mackerel sharks), which includes mako and salmon sharks. Along the California coastline, adult great whites are an important predator of marine mammals, particularly the calorie-rich elephant seals. Juveniles feed mostly on fish and add marine mammals to their diet when they reach about 450 kg.

White sharks are able to prey on such large creatures with their large upper teeth, which are triangular in shape and sharply serrated to cut large pieces of flesh from prey. The bottom teeth are narrower and used to hold prey. An unusual characteristic the white sharks (shared by other mackerel sharks and thresher sharks, Family Alopiiidae) is the ability to maintain parts of their body (swimming muscles, stomach, and brain) at temperatures above that of the surrounding water, which classifies them as //endothermic// or warm-blooded, like mammals.Many paleontologists are very interested in living groups, because the study of the living organisms can both unlock their evolutionary history and provide important keys towards interpreting their fossil record. Some living groups have ancient histories. For example, sharks have existed as a group for over 350 million years! Today, sharks and rays (elasmobranchs) are represented by over 600 species that show a remarkable range of ecological and morphological diversity. Unlike the true fishes, sharks do not have internal bone, but instead have a cartilaginous skeleton. Although many people are told that sharks are primitive in comparison to other groups, this is not true. Many sharks are efficient and specialized hunters that have thrived for millions of years.

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http://www.sharkattacks.com/