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A preserved specimen of a frilled shark at an aquarium in Paris. Credit: Citron, GNU Free Documentation License
Getting to know all the fish in the seas is a tough job. There’s a lot of ocean to cover, after all, and many species aren’t especially easy to find -- they have limited numbers or range, or they lurk in waters that aren’t often explored.
An example is the frilled shark. It looks almost nothing like most other shark species. Its body is long and sinuous, like an eel’s, and its head looks more like a snake than a fish. It has a prehistoric look, which is appropriate, since its ancestors were around at least 80 million years ago.
But biologists know little about it because the frilled shark is hard to find. The population appears to be small, and its range is limited. In fact, researchers have photographed only one specimen in its natural habitat.
Still, scientists have put together a limited dossier on this odd little shark. The adults seen so far grow up to about six feet long, and they generally swim at depths of a few hundred to a few thousand feet. The shark has six pairs of gills with frilly edges -- hence its name. It appears to eat mostly squid, and can swallow prey as much as half its own size.
The frilled shark has a mouthful of teeth -- about 300 of them, in 25 rows. Researchers speculate that the shark may float along at a depth of a few hundred feet, waiting for prey to swim by. Then it strikes like a snake, snagging a meal and using its teeth to keep it from escaping.
Despite this sketchy profile, biologists are a long way from really knowing this odd and elusive shark.
