Researchers have found out how reindeer cool themselves down when they start to overheat while running.

Reindeer grow a very thick winter coat because their bodies have to adapt to annual temperature changes of 80°C. The fur is very effective at keeping the animals warm, but scientists were puzzled as to how reindeer cool down when they run for long periods.

Now, scientists in Norway have shown that reindeer have three ways of cooling down. The first is to pant with their mouths closed. This evaporates water from inside the nose, causing a small cooling effect.

As the animals get hotter, they move on to their second tactic, panting with their mouths open. During exercise, reindeer can take up to 300 breaths every minute and their large, wet tongues allow a lot of water to evaporate.

As the reindeers’ brains reach a temperature of around 39°C, the third way of cooling begins. Instead of travelling round the body, cooled blood from the nose is diverted directly to the brain.

You can see an amazing video about reindeer swimming during their annual migration below!