Rudolph, the reindeer that pulls Santa's sleigh, actually had a glowing red nose because reindeers have more blood vessels to keep their noses warm as they graze in the snow, scientists say.
Lund University research team in Sweden has captured the phenomenon with a thermographic camera.
The video footage was filmed at the Zoo of Nordic Animals in Sweden, the world's largest zoo for Nordic animals.
Dutch and Norwegian researchers have previously discovered why Rudolph's nose is red, describing a rich supply of blood to the reindeer mule to keep it from freezing.
Lund University has taken it a step further, creating an entire research group dedicated to mammals and their noses.
"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," explained Ronald Kroger, Professor of Functional Zoology at Lund University.
This means reindeer pump warm blood into the nose in cold weather, possibly creating a reddish 'glow'.
However, not all mammals function this way.
"Dogs are the exact opposite to reindeer. Nobody knows why their noses are cold and why they have evolved that way," said Kroger.
The story of Rudolph and his red nose dates back to a book written in 1939 by Robert L May.
