Bison - Sounds Wild
Swimming Bison

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Swimming bison

In the summer of 2015, wildlife biologist Tom Seaton was flying over wet sedge meadows in interior Alaska checking on the newly introduced wood bison. As he flew over the Innoko River, he saw eight bison of the Lower Yukon/Innoko Rivers Herd swimming across the river - seven big adults and one rusty red calf. Numerous sets of tracks leading into and out of the water up and down the muddy river bank showed that bison had crossed the Innoko many times.

We don't think of bison as swimmers. Plains bison are stocky, muscular beasts, and wood bison are even bigger, with muscular shoulders and a massive shoulder hump. Plains bison and wood bison both evolved from a common ancestor, the now extinct steppe bison. Plains bison evolved in open country further south, while wood bison developed attributes better suited to the north - a heavier coat and the massive shoulders that enable them to plow through deep snow. In summer, they range across a landscape of meadows around lakes and rivers, and they are capable swimmers.

Although bison of the Lower Yukon/Innoko Rivers Herd frequently cross the Innoko River two animals are even more ambitious and aquatic. Satellite tracking shows that these two bison have explored habitat along the Yukon River between Russian Mission and Galena, swimming across the nearly mile-wide Yukon River several times.