In Canada, the term "football" may refer to Canadian football and American football collectively, or to either sport specifically, depending on context. The two sports have shared origins and are closely related but have significant differences. In particular, Canadian football has 12 players on the field per team rather than 11; the field is roughly 10 yards wider, and 10 yards longer between end-zones that are themselves 10 yards deeper; and a team has only three downs to gain 10 yards, which results in less offensive rushing than in the American game. In the Canadian game all players on the defending team, when a down begins, must be at least 1 yard from the line of scrimmage. (The American game has a similar "neutral zone" but it is only the length of the football.)

Which North American version of football calls for 12 player per side on the field?