The famous red nose is a result of densely packed blood vessels that help regulate body temperature in cold weather.

Climate Change Affects a Christmas Icon

Reindeer populations are in a downward spiral as temperatures continue to rise in their Arctic habitat

There’s actually a kernel of truth to the story of Rudolph the red-nosed reindeer — and it’s not just that reindeer actually pull sleighs. Some reindeer really do have red noses due to densely packed blood vessels in that area. These reindeer, a subspecies of Arctic caribou, have 25 percent more capillaries carrying red oxygenated blood in their noses than a human. As the temperature drops, the blood flow in and to the nose increases so the danger of frostbite is reduced, when they root around in the snow looking for food. Though it won’t light their way in a snowstorm, it keeps the surface of the nose warm and regulates the animal’s internal body temperature in frigid weather.

A group of caribou gallop across the snow. Credit: Kyle Joly, National Park Service

Reindeer are also known as caribou, with the interchangeably used terms generally referring to the domesticated and wild varieties respectively. Both of them are heavily adapted to the cold, from the tips of their (sometimes red) noses to their toes. Their hooves and footpads shrink and contract in the cold which exposes the rim of the hoof…