(SCIENCE) NORWAY – Biologists at the University of Tromso have discovered through a recent study that reindeer, Santa’s furry little helpers, cool down in a combination of ways. Similar to dogs, panting is one technique reindeer use to cool themselves as they’re unable to remove their warm winter coats. Read on for more about the other techniques used by the reindeer and the biologists’ methods in achieving such results. – Global Animal
Reindeers chilling out after a run in their natural parkas Photo credit: mentalfloss.com

New York Times, Sindya N. Bhanoo

Arctic reindeer have thick fur coats that help them survive frigid winters. But they also need to cool off in the winter when their bodies grow warm from running.

Now, researchers have discovered that reindeer use a combination of strategies to keep cool. Arnoldus Blix, an Arctic biologist at the University of Tromso in Norway, and his colleagues describe their findings in The Journal of Experimental Biology. “You dress up in winter, and if you run around you get very warm, so you open up your coat and take off your hat,” Dr. Blix said. “Reindeer can’t do that; therefore we looked at the mechanisms of how they manage.”

To conduct their study, Dr. Blix and his team trained reindeer to run on a treadmill at different temperatures, from 50 to 86 degrees Fahrenheit, and recorded the animals’ responses.

They found that reindeer start cooling off by panting with their mouths closed and inhaling cold air through their noses. This cools the blood inside the nasal passages, and eventually this cooler blood is distributed throughout the body via the jugular vein.

When this isn’t enough, reindeer also pant with their mouths open and their tongues hanging out, as dogs do. This cools their blood more efficiently and also allows them to lose heat through their mouths, by evaporation.

In critical situations, when their bodies are heating to a dangerously high temperature, reindeer resort to a final defense mechanism. They divert cool blood from the nose toward the head, protecting the brain from overheating.

More New York Times: http://www.nytimes.com/2011/11/01/science/staying-cool-after-a-slog-with-a-sleigh-isnt-easy.html?_r=1&ref=animals