© Kt Miller/Polar Bears International
4/24/2019 3:20:41 PM
Polar Bear Questions: Do Polar Bears Drink Water?
By Dr. Thea Bechshoft
We’re back with our Polar Bear Questions series with a query from Lars: "Do polar bears drink water and, if so, where do they find it? Living in a frozen world does not supply a lot of liquid fresh water."
Good question, Lars! Polar bears do indeed live most of their life out on the sea ice, surrounded by saltwater, which is no good for drinking. However, the bears have found a couple of ways to get around this lack of drinking water.
Polar bears will sometimes eat snow, but usually not in great quantities as it requires energy to melt it. Eating snow tends to be something the bears also do when they want to cool down, for example after sparring/fighting or on a sunny day.
Polar bears will also have a drink at the freshwater melt ponds that can form on the sea ice during the warmer months of the year. In the ice-free summer months on land, they will drink water from the freshwater ponds dotting the landscape.
Furthermore, cubs get nutrients and water from drinking their mother’s milk until they are weaned at about 2.5 years old.
Another interesting way that polar bears get their water is—however odd this may sound—by eating as much seal fat as they can lay their paws on. When catching a seal, a polar bear will eat the energy-rich fat (blubber) first, often leaving the meat behind.
There are several reasons for this, but one of them is that the physiological process of metabolizing (breaking down) meat protein requires water from the body, whereas the breaking down of fat actually releases water. In other words: The more fat the polar bear eats, the less water it will need to drink. This holds true regardless of whether the bear is burning recently eaten seal fat or burning its own fat deposits.
However, burning fat for hydration is not the most efficient process: that's because, in freezing cold conditions, oxygen intake plays a role in producing metabolic water. At low humidity, burning fat is less efficient and polar bears need to breathe more to get the necessary oxygen to support water production. It’s all about balance.
Dr. Thea Bechshoft is a polar bear scientist based in Aarhus, Denmark, and part of the Polar Bears International team. She is the author of the popular Polar Bear Questions page on Facebook, republished here with permission.