The tale of Rudolph's red nose has long been a Christmas classic -- and now researchers in Sweden have caught the reindeer's glowing nose on camera.
Scientists at Lund University used a thermographic camera to film reindeer at the Zoo of Nordic Animals in Sweden.
They discovered that Rudolph's nose is "red" due to the rich supply of blood the animal needs to pump to its nose to keep it from freezing.
"When reindeer are feeding, their mules are exposed to very low temperatures as they look for food under the snow," Professor of Functional Zoology at Lund University Ronald Kröger said in a press release. "They need to maintain sensitivity in order to know what they're actually eating."
They do so by sending warm blood to their cold noses -- creating the reddish "glow" Rudolph the red-nosed reindeer is named for.
Not all mammals function this way, the researchers said. Kröger is a dog owner and part of the Mammalian Rhinarium Group at Lund University, which studies how mammals obtain sensory information from their specialized, hairless and wet nose tips (called rhinaria).
“Dogs are the exact opposite to reindeer. Nobody knows why their noses are cold and why they have evolved that way. That is what we want to find out,” he said.
Watch Rudolph's nose glow in the video below.