5. The sharkâshaped by evolution to be a swift, powerful predator and a fearsome menace to swimmersâis now itself becoming prey to manâs insatiable appetite for exotic foods. Worldwide shark populations are dropping to alarming levels, and several species are already endangered. It is estimated that populations of some species have declined by 90%.
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7. Flaring the gills that give the species its name, a frilled shark swims at Japan's Awashima Marine Park on Sunday, January 21, 2007. Sightings of living frilled sharks are rare, because the fish generally remain thousands of feet beneath the water's surface.
