Tuesday, October 18, 2011

Basking sharks

a migratory speciesal though its seasonal movements aren't well known. They dwell in northern waters as long as the plankton population is abundant, moving south in the winter. Though they are largely oceanic sharks, they can be found off the coast of Iceland and northern Europe during the summer where they mate.

this shark swims with its mouth open widely, gillrakers straining plankton from the water. The absence of basking sharks in the winter has led to the belief that they hibernate in deep waters until the following summer and, since they lose their gill rakers in winter, possibly cease to feed during this time.

Basking sharks inhabit subpolar and temperate seas moving southward during the winter. They prefer surface waters of the open sea, straying inland only to breed in the summer. basking shark has a conical snout, enormous gills, dark bristle-like gill rakers, and a crescent-shaped tail. Teeth are small and numerous(about one hundred per row) with a single conical cusp usually curved backwards, and similar in both jaws. Color is grayish brown to black above, often with blotches of a lighter color, and pale with blotches on the belly. Average size of this shark ranges from 7-9 m.

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