Shedding Light on Fur Primeness

A few recent posts on trapping and predator hunting message boards have my hide a bit chapped.

Let’s do away with the following myth: Cold weather causes animals’ fur to become prime. Weather has nothing to do with it. An animal’s fur thickens and becomes prime because of decreasing daylight. The animal – whether it’s a coyote, fox, beaver, raccoon or black bear – grows a thicker coat when the amount of light (called photoperiod) shortens. Less light triggers a chemical secretion in the animal that spurs the hair follicles to produce dense underfur and longer guard hairs.

A raccoon’s coat will be just as prime in November if the weather is unseasonably warm as it will be if we experience prolonged record cold in October. Biologically, animals need to have that thick fur blanket in place before winter rages across the landscape. We can just get an extra blanket out of the closet, but a coyote or fox needs to be wearing its protection before the weather gets nasty. If animals’ bodies only grew fur after the cold weather hit, they’d all freeze to death during the first cold snap.

Researchers have conducted experiments on mink that show temperature has nothing to do with fur primeness. In one study, mink were subjected to decreasing periods of light in the summer for six weeks. The mink all grew heavy coats, and the fur density and quality was similar to what would be expected of a mink in November. These mink were kept in normal summer temperatures. The amount of light was the only variable changed.

Incidentally, changes in photoperiod spur breeding behavior in many animals, including several furbearers. It also causes bird migrations, antler growth in deer and the changing of the color of leaves.

So the next time the discussion about what makes fur prime comes up, remember: It’s all about the light.