insulation is just a fancy way of making air stand still. in minnesota one of the concepts you grow up knowing about is r value. windows, doors, fiberglass insulation, down jackets, all have an r value, meaning a particular resistance to the infiltration of heat or cold. when air is moving, it has almost no r value. that’s why wind feels so cold. trapped air, on the other hand, has the kind of r value that can keep you warm through the coldest night. it’s something you think a lot about when you live in minnesota with a short haired dog, a small flock of fluffy chickens, a newly balding husband, and 30 below windchill blowing in across turtle lake. the coyote in this photo trapped a lot of air inside that wiry fur. it kept him warm through several winters, until something blew in from highway 88 that couldn’t be resisted with r value.

coyote tail

minneapolis, minnesota