Facts on Northern Michigan animal fur are brought to you by one of our favorite biologists, Dr. Philip Myers, curator of University of Michigan’s zoological collection and founder of Animal Diversity Web (animaldiversity.org). When we contacted him to share some of his choicest fur factoids, he wrote back, “Interesting topic, and dear to any mammalogist (like me).” We knew we had the right Northern Michigan outdoors man.

It seems every animal’s fur is beautiful in its own particular way—does fur differ that much among species?
Yes. Actually, each mammal’s hair type is so distinct that a biologist studying a single piece of hair with a microscope can usually identify exactly which animal produced it. Researchers are using this fact to study, for example, the range of lynx in Northern Michigan right now. They put out hair snares—pieces of wire designed to snag a little tuft of hair from an animal walking to a bait—to see if any lynx are in the area. Other researchers are taking hair study a step further by inspecting the DNA in the hair to reveal the genetic diversity of a specific species in the area. Michigan’s pine martens have been studied this way.

Is it true that polar bear hair is not white but is actually transparent, and just appears white?
Yes—sort of. Only the longer guard hairs are transparent. Polar bear hair is also hollow, as is body hair of white tail deer, elk, caribou, antelope and some others. The hollow, honeycombed hair structure traps air, which is a great insulator.

Just how warm does fur keep a Northern Michigan animal?
Well, it depends of course, on the animal and how thick its fur is. But one way scientists gauge this is to compare the temperature at which an animal’s metabolic rate speeds up to keep warm when in summer fur versus winter fur. One study of red foxes showed that the fox metabolic rate kicked into higher calorie-burning mode at 50 F in summer fur, but in winter fur, the higher metabolic rate didn’t begin until 14 F. (Cool bonus fact: scientists check the rate of calorie-burning by measuring how rapidly the animal is consuming oxygen.)

When a snowshoe hare or a weasel turns white in winter, is the hair changing color?
Well, most mammals molt, that is, lose and replace a large portion of their hair, once or twice a year. With the snowshoe hare and weasel, they shed their dark summer coat, and the new winter hair comes in white. The white tail deer is another example of fur color change through molting, though not so dramatic. The reddish summer coat is replaced by the gray winter coat.

Fur Terms—get it right.

Pelage: What we commonly think of as a fur or pelt; all the hair covering the animal.
Guard hair: The most conspicuous hair on the animal; the porcupine quill is an especially stiff (and barbed) guard hair.
Underfur: Protected by the guard hairs, this can be made up of wool (ever-growing hair), fur (short hairs with defined length), and/or velli (down or fuzz).
Lanugo: The pelage that covers mammalian embryos (including human embryos).
Source: Animal Diversity Web

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