© Kt Miller/Polar Bears International
3/12/2019 2:08:24 PM
Polar Bear Questions: Breathing in Cold Air
A friend recently asked me this great question: “When we breathe in very cold air, it can make us cough and generally be bad for our lungs. How do polar bears avoid such troubles?”
Why does cold air make us cough?
There are two main reasons why cold air can make you cough and generally have unpleasant effects: a) it’s significantly colder than the temperature in your nose/mouth/throat/lungs and b) it contains less moisture than the membranes that line your throat, lungs etc. These membranes are thus dried out by the incoming air, which leaves them irritated and more vulnerable to infections.
Polar bears are protected by their long muzzle
Unlike many humans, polar bears don’t appear to have any respiratory problems brought on by cold air. The reason for this: polar bears have a much longer muzzle (nose) than humans do. This means that the air that is inhaled has more time to get warmed up and rehydrated in a polar bear nose than it does in a human nose.
In addition, polar bears have what is called turbinate bones in their nose: very thin and curly bony plates—an absolutely beautiful structure that is easily seen on a cleaned-up polar bear skull (see photo below).
Front view of polar bear skull by Dr. Hanneke Meijer
The turbinates are fragile structures. (If you see a polar bear skull in a museum without turbinates it’s simply because they broke and fell out during the cleaning process.) The turbinates are covered in the same kind of mucosal membrane as the rest of the inside of the nose and, due to their convoluted structure, increase the inner surface of the bear’s nose immensely—in effect making it even bigger.
The turbinates in the front of the nose generally aid in heat and moisture retention, whereas the turbinates at the back of the nose aid in olfactory function, and as such are key to the polar bear’s impressive sense of smell that allows them to locate seals from far away and find seal pups in lair under the snow and ice.
If only humans had a longer muzzle too...
Humans also have these turbinates (or nasal concha as they are also known), but to a much smaller extent. Google “human turbinates” if you want to see for yourself. They are important structures in us, too, helping in the filtrating, heating, and humidification of the air we breathe. However, our muzzle (nose) just isn't long enough to offer any serious protection against deep Arctic cold!
Dr. Thea Bechshoft is a polar bear scientist based in Aarhaus, Denmark, and a part-time staff member of Polar Bears International. She is the author of the popular Polar Bear Questions page on Facebook, republished here with permission.