Sharks

Rough Sagre Shark

posted: 04/11/12
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Overview - The rough sagre is also known as the great lanternshark. The name comes from the fact that many sharks in this family can emit a green light from their bellies. The light results from organs known as photophores that may line certain parts of the shark's body. The organs either emit light from special internal structures, or they derive light from symbiotic luminescent bacteria. At present, there is some debate as to whether or not the rough sagre possesses photophores. There is no doubt, however, that this shark is adapted to exist under very dark conditions. At depths of up to 7,300 feet, this Atlantic Ocean shark is far removed from any hint of sunlight. One interesting feature of this mysterious shark, which has been confirmed, is that it possesses denticles on its skin. Denticles are small skin outgrowths that resemble tiny teeth. Some people even used to employ sharkskin containing these outgrowths as sandpaper, since it results in a rough surface.

Feeding Habits - Not much is known about the diet and feeding behavior of the rough sagre. Its teeth provide some clues. The upper set contains smooth-edged cusps that are handy for slicing. The lower set is more sharp and angled, which likely helps the shark to hold onto slippery prey.

Cool Fact - Early Japanese sword makers used to use denticle-covered sharkskin, similar to what is found on the rough sagre, when making slip-resistant sword handles.

Depth - 7,300 feet

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