I've done a fair amount of field biology work and would always run wherever we were. I've come up on grizzly and black bear, wolves, coyotes, badgers, rattlesnakes, moose, elk, deer, eagles, marmots, frogs... I got within about 6 feet of a black bear accidentally one time, within arm's reach of a big bull moose when coming through a tight corner in the woods (the most freaked out I've been), been close enough to a badger that it started hissing and lunging at me, and the rattlesnake could have striked my ankle had it wanted to as it was on the edge of the two track I was running on...
If I were to live in grizzly country again I would probably carry bear spray with me. Nothing else really scares me, except mountain lions, but given their ambush style of hunting, if one of those lands on you you're probably a goner regardless. The wolves were really cool, but they were a good quarter mile away. Elk, deer, antelope, etc are all very common and not exciting at all after about the 3rd time. The badger was pretty cool as it was really acting tough. Coyotes are cowards... bison and moose are scary as they can be kind of unpredictable (especially bison) and they can easily destroy you if they want.
I have to wonder how many Africans train. According to a South African biologist I know, simply spending an hour in the bush right outside of town was pretty much a death wish unless you had a gunman with you. He may have been exaggerating though.