Foaled in 1908, the grey mare Rena Bison was bred by Joseph Darraugh of Orangeville, Ontario, and later owned, trained and driven by Clifford Chapman Sr. of Saskatoon, Saskatchewan. She was the Canadian champion race-winning mare of 1920 at the age of 12. Rena Bison started in 102 heats that year, winning 40 and also had 34 seconds and 18 thirds. She raced that season at Balcarres, Cupar, Indian Head, Saskatoon, Punnichy, Lloydminster, Prince Albert, Yorkton, Semanus, Melfort, Hanley and Deslisle in Saskatchewan and at Dufferin Park, Canadian Exposition Park, Brampton, Milton, Oshawa, Simcoe, Hamilton, Lindsay and Peterborough in Ontario. She lowered the Canadian National Exhibition Park track record to 2:11 1/4, her lifetime record, in 1920. During her career, which started in 1913 and ended in 1922, Rena Bison won 62 of 240 heats and added 58 seconds and 46 thirds.