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Experts discover why Rudolph's nose is red

Date:
December 17, 2012
Source:
BMJ-British Medical Journal
Summary:
Rudolph's nose is red because it is richly supplied with red blood cells which help to protect it from freezing and to regulate brain temperature.
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Researchers analyzed a reindeer's temperature while on a treadmill. In the arctic, reindeer have evolved to keep warm - but like all animals, sometimes they need to cool down. Unlike humans, they cannot sweat, so have to use their nose as a heat exchanger.
Credit: Image courtesy of BMJ-British Medical Journal

Rudolph's nose is red because it is richly supplied with red blood cells which help to protect it from freezing and to regulate brain temperature.

This superior "nasal microcirculation" is essential for pulling Santa Claus's sleigh under extreme temperatures, reveals a study in the Christmas issue published on the British Medical Journal website.

Tiny blood cells (known as micro-vessels) in the nose are vital for delivering oxygen, controlling inflammation, and regulating temperature, but few studies have assessed their function in detail.

Knowing how important this regulation is for flying reindeer, who have to deal with extremes of temperature while pulling a sleigh, researchers in the Netherlands and Norway set out to test whether Rudolph's infamous red nose was due to "a highly dense and rich nasal microcirculation" compared with human noses.

Using a hand-held video microscope, they first assessed the noses of five healthy human volunteers and found a circulating blood vessel density of 15 mm/mm2.

When the technique was applied to two reindeer noses, the researchers found a 25% higher density of blood vessels, carrying a super-rich concentration of red blood cells.

They also found a high density of mucous glands scattered throughout the reindeer noses, which they say helps "maintain an optimal nasal climate during changing weather conditions and extremes of temperature as well as being responsible for fluid transport and acting as a barrier."

Infrared thermal images showed that reindeer do indeed have red noses.

"The microcirculation of the nasal mucosa in reindeer is richly vascularised and 25% denser than that in humans," say the authors. "These factors explain why the nose of Rudolph, the lead flying reindeer employed by Santa Claus to pull his sleigh, is red and well adapted to carrying out his duties in extreme temperatures."

Video: http://www.youtube.com/watch?v=sbnvBm4u5VQ


Story Source:

The above post is reprinted from materials provided by BMJ-British Medical Journal. Note: Materials may be edited for content and length.


Journal Reference:

  1. C. Ince, A.-M. van Kuijen, D. M. J. Milstein, K. Yuruk, L. P. Folkow, W. J. Fokkens, A. S. Blix. Why Rudolph's nose is red: observational study. BMJ, 2012; 345 (dec14 14): e8311 DOI: 10.1136/bmj.e8311

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BMJ-British Medical Journal. "Experts discover why Rudolph's nose is red." ScienceDaily. ScienceDaily, 17 December 2012. <www.sciencedaily.com/releases/2012/12/121217190634.htm>.
BMJ-British Medical Journal. (2012, December 17). Experts discover why Rudolph's nose is red. ScienceDaily. Retrieved September 4, 2015 from www.sciencedaily.com/releases/2012/12/121217190634.htm
BMJ-British Medical Journal. "Experts discover why Rudolph's nose is red." ScienceDaily. www.sciencedaily.com/releases/2012/12/121217190634.htm (accessed September 4, 2015).

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