This Europe: Hardy swimmers share ice-hole with wily rodent

Winter swimmers in the Aland Islands between Finland and Sweden have been putting up with more than the cold recently.

The Baltic Sea has frozen over, and an ice-hole kept open for swimmers in the Lilla Holmen Park in the islands' capital, Mariehamn, has been taken over by a large and fearless muskrat.

"With 40cm of ice on the bay, it's hard for animals and birds to find open water," said Maria Bjorke, who swims twice a week – even when air temperatures fall to minus 20C. "We have a heated changing room, and the town council keeps the ice-hole open." About 150 people use the facility.

The muskrat has built a nest under the steps leading into the ice-hole. Though he dives when swimmers approach, he is liable to pop up at any moment – giving bathers a nasty shock. When he charged at one elderly female swimmer, the council decided enough was enough. A trap was set, but the wily creature has proved elusive.

Muskrats, which are herbivorous, can grow up to 2ft long. "We've had to share our ice-hole with ducks as well, but no one minds about them," Ms Bjorke said.