Part of that is the natural inclination for the same family of mammals to grow larger the further north you go. By the time you get to Canada, the blacks are just about as big as the browns - and sometimes more aggressive. A 500- to 700-pound black bear doesn't react to humans shouting and throwing rocks quite like a 200-pounder in the Sierra might.
Still, though, grizzlies make me nervous. I quit carrying Counter Assault in most bear territory that I hike in often (Georgia and California, mostly) - blacks are basically wussies in these two states. Anywhere in range of the Canadian border, though, and I'm locked and loaded with serious pepper spray.
