An investigation into the origin of Rudolph the Reindeer’s red nose has ended the generations-old debate by uncovering an elusive but long-hypothesized scientific explanation: A snootful of red cells.

Detailed evaluation of adult reindeer’s nasal microcirculation revealed similarities with human nasal microvasculature, but also striking differences. Reindeer nasal microcirculation exhibited a highly vascularized nasal mucosa, a red cell-rich nasal septal mucosa, and a microvessel density 25% greater than that of humans.

The architecturally distinct nasal microvasculature confers on Rudolph a nose that “is red and well adapted to carrying out his duties in extreme temperatures…”

“These results highlight the intrinsic physiological properties of Rudolph’s legendary luminous red nose, which help to protect it from freezing during sleigh rides and to regulate the temperature of the reindeer’s brain, factors essential for flying reindeer pulling Santa Claus’ sleigh under extreme temperatures,” Can Ince, PhD, of Erasmus Medical Center in Rotterdam, the Netherlands, and co-authors wrote in conclusion.

The findings are consistent with an inherent adaptive mechanism in reindeer vascular development to deal with the cold climate, according to a researcher who was not involved in the study.

“In colder climates and also when they are higher up in the atmosphere pulling Santa’s sleigh, the increase in blood flow in the nose will help keep the surface warm,” John Cullen, PhD, of the University of Rochester in New York…

If alcohol does play a role in the color of Rudolph’s nose, the study has implications that extend beyond well beyond a single reindeer.

“I think [the message] will be ‘Don’t let Santa drive drunk,’ because he won’t be able to deliver the presents,” said Cullen…

The authors reported that Santa Claus offered “enthusiastic support” for this study.

RTFA for more intricate details of the study including quantification of nasal microcirculation.

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