Moose cavalry are military units of cavalrymen mounted on moose (AKA Eurasian elk, Alces alces alces) rather than the more usual horses. Some sources[who?] state that in 17th-century Sweden Charles XI trialled the use of moose as a replacement for horses, which had to be imported, but this is disputed. The use of moose cavalry by the Soviets in the Winter War of 1939 and 1940 is also reported but seems to stem from a 2010 Popular Mechanics April Fools' Day article.