A beaver by any other name...
Market research showed us that younger Canadians and women were very very unlikely to ever buy a magazine called The Beaver no matter what it's about.
For whatever reasons, they are turned off by the name.
A number of alternative names were considered - vulva, mons veneris, pudendum and the rather obscure squirrel -- with editorial staff eventually opting for the boringly descriptive Canada's History.
Update: Canadian Leslie Nielsen spies a beaver: