On a cold dark November night, a lynx stands on the banks of the Tanana River south of Fairbanks. The river has not yet frozen, but large plates of ice swirl in the current. The lynx wades into the freezing water and begins swimming across the river.
Researchers with the University of Alaska Fairbanks collared 23 lynx between 2008 and 2012. Knut Kielland and his colleagues are studying lynx movements and learning about habitat, activity patterns, and dispersal. The collars allowed them to precisely track the movements of these northern wild cats.
They were surprised to learn that several of the animals repeatedly swam across the Tanana River in October and November, in freezing weather but before it froze solid. The Tanana is a large, swift, glacial river; it is the largest tributary of the Yukon River and more than a mile wide in places, with braided channels. One male crossed the main channel of the river six times in November. Another male crossed the Tanana 14 times Tanana between September and November, and swam across sloughs and channels of the river (up to 50 meters wide) an additional 20 times. A female lynx swam across the river 11 times and swam across smaller braids, channels and sloughs 40 times in freezing cold weather.