Narwahl: the origin of the unicorn's myth?

The narwhal, or narwhale, Monodon monoceros, is a medium-sized toothed whale that lives year-round in the Arctic. One of two living species of whale in the Monodontidae family, along with the beluga whale, the narwhal males are distinguished by a characteristic long, straight, helical tusk extending from their upper left jaw. 


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The most broadly accepted theory for the role of the tusk is as a secondary sexual characteristic, similar to the mane of a lion or the tail feathers of a peacock.This hypothesis was notably discussed and defended at length by Charles Darwin, in The Descent of Man, and Selection in Relation to Sex (1871). It may help determine social rank, maintain dominance hierarchies, or help young males develop skills necessary for performance in adult sexual roles. Narwhals have rarely been observed using their tusk for fighting, other aggressive behavior or for breaking sea ice in their Arctic habitat.


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Narwhal have been found to be one of the most vulnerable arctic marine mammals to climate change. The study quantified the vulnerabilities of 11 year-round Arctic sea mammals. Narwhals that have been brought into captivity tend to die of unnatural causes.

sources: http://en.wikipedia.org/wiki/Narwhal
http://compendiumofawesome.wordpress.com/2010/09/02/narwhal/
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