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"Alien Sharks of the Deep" Shark Week 2013

A frilled shark, a very old type species of shark, sometimes called a living fossil. Part of red gills are exposed to efficiently take oxygen from the water in the abyss containing much less oxygen than near the surface.

'Alien Sharks of the Deep' Gets Weird

Discovery's new Shark Week special "Alien Sharks of the Deep" shines a light on the darkest corners of our oceans to reveal some truly strange sharks. Here are five of the creepiest fish you'll see this Shark Week. — Robert Chan, Yahoo! TV