As Europeans invaded North America, one of the most important trades was that of the trapper and furrier. Many different animal species were prized for their pelts, including beaver, hare, lynx, and ermine. The first skins were usually bartered from native people and used for personal comfort. Later, these skins would be bought wholesale from hunters and trappers and sent back to Europe (an extremely profitable enterprise). In places this was the dominant meeting point of the two cultures, native and European, and economic goals often financed British, French, and Dutch explorations into the continent’s interior.
Of course, being such a profitable enterprise it behooved the company to keep very detailed records of its suppliers and customers, as well as each region’s production for the year. They were dogmatic. This has led to some of the oldest and most detailed economic records available for North America.
One of the largest companies to control the fur trade was the English incorporated Hudson Bay Company (abbrev. HBC). It has been active since 1670 and for a while acted as the de facto government huge swaths of Canada. Today, it no longer trades in furs, instead owning and controlling several retail stores. But the very nice thing about the HBC (from a naturalist’s view) is that they’ve publicly released their old trapping records for viewing.
Biologists have jumped on this data like fleas to a hemophiliac dog. Such precise information allows us to delve deeply into populations that were around hundreds of years ago. If we suppose that hunters were consistently skilled from year to year, we can guess the animal population of a region just by looking at the fur records. One of the most famous examples of this is the Lynx-Hare cycle.
Predators and prey exist in a fluctuating relationship. If there are too many wolves, deer populations drop. If there are too few, the deer numbers explode (we can see this today in the fact that white-tailed deer are everywhere now that wolves are gone). Similarly, lots of food means lots of wolves and vis versa. The following is a graph based on the numbers provided by the HBC of their lynx and hare pelts from 1850 to about 1930.
We can see that every spike in hare pelts is followed by a spike in the number of lynx. And every time the hares become rare, the lynx follow suit. The populations are linked in oscillation. These Hudson Bay Company pelt numbers are invaluable for showcasing predator-prey relationships and illuminating that wild populations of animals don’t exist in isolation. Nature is a complex pattern, all wrapped up in itself. Everything is affected by everything else.
Any scientist will tell you. Good record keeping is a godsend.
Even if it comes from a trapper in Canada.