Sunday, February 13, 2011

Creature Feature: Cookiecutter Shark.

And now for something completely different: A shark that makes perfectly circular wounds with its teeth.

These cuts were made by a shark. Not a lamprey. Not a crazy sea worm from some B-horror movie. A shark, as in, related to Jaws. It lives in only a few little spots in the ocean, but those spots are riddled with hole-pocked animals.

This shark has binocular vision, just like Prasina vine snakes and humans.

The cookiecutter shark (Isistius brasiliensis) is one of the smaller shark species referred to as 'dogfish.' These are not the same sharks as the menacing Tiger and Great White species; they are a lot smaller (14-15 inches at most), which honestly makes them creepier when looked at head-on. The cookiecutter shark is particularly uncanny in this regard - it has binocular vision and a mouth straight off of an alien monster.

The  cookiecutter's crazy, suction-like mouth almost looks like it does not belong on a shark. It nonetheless fits the cookiecutter's semi-parasitic life style; cookiecutter sharks swim around taking bites out of whatever they happen to encounter. These chunks are usually 2 inches (5 cm) in diameter and 2.8 inches (7 cm) deep. They can appear on anything - fish, other sharks, whales, dolphins, undersea cables, submarines, human bodies, anything. The U.S. Navy was once forced to retreat because the sharks had caused their submarines to leak. Our finest, everyone!

Besides the strange cutting pattern, the cookiecutter shark also has a number of other weird things about it. It undergoes a migration from miles beneath the sea (literally the "twilight zone") to the surface every day. Oblivious porpoises and other predators may mistake the school of sharks for much smaller, tastier fish thanks to some of the best countershading on the planet.

The cookiecutter shark may look rather drab on top, but it possesses photophores on its underside that make it glow in the dark (a feat so amazing that creationists are all over a creature CLEARLY from the damper reaches of Hell). Its underside glows bright green except for one strange, collar-like ring around its neck (thus a scientific name derived from "Isis," the Egyptian goddess of light). Glowing in the dark is pretty cool, but the collar baffles scientists; the current theory is that it serves as a lure,  making this the first recorded instance of reverse-bioluminescence as a hunting mechanism. Trippy.

Tomorrow: Happy Valentine's Day! Those kissing fish are not as lovey-dovey as one may think.

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