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September 23, 2016
Q. Picture a gaping mouth and pointy teeth in a watery expanse, and what comes to mind? Seems pretty accurate for a shark, doesn't it?
A. Yes, if you're thinking of the great white shark from the classic movie “Jaws,” but you'd be ignoring the other 500 species of shark varying in size, shape, environment and diet, says Gemma Tarlach in Discover magazine. Some are so small they could fit in your hand, such as the dwarf lanternshark; others are so big they grow up to 40 feet long, like the whale shark. Common characteristics include jawbones, multiple gill openings, and skeletons of cartilage. Sharks lack an air-filled swim bladder to control buoyancy, instead relying on their large, oily livers as a kind of internal flotation device. And while many shark species are coldblooded, some like the great white shark are warmblooded so they grow faster, swim faster and hunt more efficiently.
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