Jan 16, 2012 5:03 PM
The recent cold snap prompted many of us to don our winter garb: hats, gloves, and an extra layer of clothing or two. When the temperature drops, we rely on increasing the “R-value” of our clothing.
But what about the birds and mammals that are active throughout our winter season? Many of these species develop high R-value winter coats: extra long and dense hairs in the case of mammals, and denser, thicker feathers in the case of birds. In both cases, as with our long underwear and down coats, the goal is to trap warm air next to the body. And just as a winter camper will shake and fluff up his or her sleeping bag to increase its loft, birds will fluff up their feathers on particularly cold days to... more
But what about the birds and mammals that are active throughout our winter season? Many of these species develop high R-value winter coats: extra long and dense hairs in the case of mammals, and denser, thicker feathers in the case of birds. In both cases, as with our long underwear and down coats, the goal is to trap warm air next to the body. And just as a winter camper will shake and fluff up his or her sleeping bag to increase its loft, birds will fluff up their feathers on particularly cold days to... more
more
