Mathematics and Biology

Animals of the boreal forest.
Population Cycles in Mammals

Math Awareness Month 1999

What are cyclic fluctuations?

he fur trade is as old as the presence of Europeans in North America.  The Hudson's Bay Company operated trading posts in the North Woods for centuries, trading European goods for the furs of foxes, martens, ermines, hares, and lynx. 
The fur trapping records of the Hudson's Bay Co. furnish one of Ecology's longest data sets.

Painstakingly excavated in the 1940s by Elton & Nicholson, the sales records of the Hudson's Bay Company remain a touchstone for ecological investigations.  Not only do they form one of the longest ecological data sets in existence, but they strikingly demonstrate the existence of a phenomenon long known among trappers.

The pelt harvest records clearly show the existence of "cyclic fluctuations" in the abundance of most furbearing species.  The cycles are clearest, however, for the lynx.


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