Since agriculture officials first discovered the snail invasion in 2011, trappers have collected more than 117, 000.

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Farmers and trappers prepare skins by scraping off the fat, then stretching and drying the pelts.

FORBES: Adventures in the Skin Trade

Dennis Gast, a game warden who catches muskrats in his spare time, is one of this area's most admired trappers.

WSJ: Muskrat Love: Exuberant Demand Pays Off for Great Lakes Fur Trappers

In the western half of the continent, Mexican packers met English and French trappers and explorers, and traded their packing tricks.

ECONOMIST: New uses for an old pastime

Mr Qillaq, who chairs the Kanngiqtugaapik Hunters and Trappers Organisation, laughs at the notion that hunting will harm the polar bear population.

ECONOMIST: A clash between environmentalists and Inuit rights

The Fur Auction got its start in 1670 as the Hudson's Bay Company, which bought furs from trappers and shipped them to London.

FORBES: Adventures in the Skin Trade

Swelling demand pushed trappers farther west, cutting new trade routes, expanding a young nation's borders and creating the first American multimillionaire, John Jacob Astor.

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Some trappers are hedging their bets against a belly bust.

WSJ: Muskrat Love: Exuberant Demand Pays Off for Great Lakes Fur Trappers

When the U.S expanded westward beyond the Alleghenies in the early 19th century, the topographical engineers, whose task was to survey the land into townships and sections before it was settled, immediately followed the fur trappers.

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That got trappers' attention.

WSJ: Muskrat Love: Exuberant Demand Pays Off for Great Lakes Fur Trappers