In a perfectly seasonal bit of science, a team of researchers in Sweden have discovered the basis for fact in the Rudolph the Red-Nosed Reindeer story: reindeer really do have red noses, of a sort.
Reindeer, the European version of caribou, feed on lichens, moss and grasses that remain beneath the snow in their cold northern homes. To find them, they have very sensitive noses, which function like our own hands -- they can feel for food just by nudging items around with them. But as our hands get cold, so would their noses. Says Ronald Kröger, of Lund University, which conducted the research:
"When reindeer are feeding, their mules are exposed to very low temperatures as they look for food under the snow. They need to maintain sensitivity in order to know what they're actually eating."
So in cold weather, reindeer pump more blood into their noses to keep it warm and sensitive, leading, according to this team, to a "reddish glow." You can see it for yourself in the heat-sensitive video below: