Larter, N.C., J.S. Nishi, T. Ellsworth, D. Johnson, G. More and D.G.
Allaire. 2003. Observations of Wood Bison Swimming Across the Liard
River, Northwest Territories, Canada. Arctic 56(4): 408-412.
ABSTRACT
We observed a group of 18 wood bison, of mixed sex and age
classes, swimming across a 1.7 km wide section of the Liard River on 16 July
2002. Water levels and flow rates were above the long-term average for that
time of year, and there was a river current of 14 –16 km/h. The animals took
at least 27 minutes to negotiate their 3.6 km swim. Younger animals were
able to keep more of their head and body above the water level than older
mature males. Calves of the year, observed swimming across a secondary
channel of the river on 15 July 2003, had only their heads above water.
Bison are capable of swimming across lakes and rivers (Wood Buffalo National
Park, Yellowstone National Park), but well-documented cases of bison
navigating rapidly flowing northern rivers are rare. Open-water crossings of
the Liard River are important to the ecology of the Nahanni wood bison
population, especially since seismic activity in the Liard River Valley is
likely to increase.
