Reindeer do have red noses, due to a high concentration of red blood cells. The four-legged animals have at least 25% more blood cells in their noses than humans.
While this may have the side effect that Rudolph can light up Santa’s path, the nose has developed in this way to protect the reindeer against extreme cold. The increased blood circulation in the nose prevents freezing mucosa and helps regulate the brain’s temperature.
It can, however, be difficult to see the red nose because many reindeer are greyish brown with dark skin on their noses. In white reindeer, the nose becomes red after physical exercise – just as people get rosy cheeks due to blood circulation.
In an experiment with reindeer on a treadmill, infrared camera data showed the nose as red, and around 24 degrees Celsius.
