Could a polar bear swim from Greenland to Iceland?

Answer

Stamina and resistance to the elements are among the main attributes of the polar bear. These bears can run rather fast and maintain speed for long periods, so stamina is probably their main strength.

Of all bears, the polar bear is best adapted to living in water. As one can see from the Latin name Ursus maritimus, it is sometimes called a marine bear. Its great stamina is best seen in its long swims. The bear will swim across a fjord or strait without hesitation and research has shown that it can swim at 10 kph. There is a record of an adult polar bear having swum up to 100 km, where the swim took 11 hours! There is another confirmed record of a polar bear having swum 320 km, which is the longest recorded swim for a bear, but the duration of the swim is not known.

Polar bears swimming.
The distance between Iceland and Greenland, where Greenland Straits are narrowest, is about 300 km. One could then conclude that a polar bear could swim from Greenland to Iceland, but might have to rest on the way. There are no confirmed records of such a swim between the two countries.

When polar bears have come to Iceland they have usually travelled most of the way on icebergs that continuously drift south along Greenland's east coast. So they cannot make their own way back to their natural habitat, as there is little point in getting on an iceberg off the shore of Iceland as it will continue to drift south and finally melt! This is one of the reasons why the polar bear has not colonised Iceland.

Another reason is that the polar bear's forage is very specialised and related to sea ice. It involves killing seals in a special manner, at the ice edge or in gaps in the ice. This kind of foraging would not be very productive in Iceland. Given this foraging, the Icelandic name ísbjörn (ice bear)) is particularly appropriate for this species of bear; they are very dependent on ice.

The polar bear's physical attributes show how well it is adapted to water. It is more streamlined than other bears and its thick layer of fat (up to 11 cm) protects it from the cold.

Translated by Paul Richardson.

Picture:

• Polar Bears: A SeaWorld Education Department Resource