The Grizzly (Ursus arctos horribilus) is a subspecies of the Eurasian Brown Bear (Ursus arctos) and for all intents and purposes the same animal. There are several subspecies, but basically the only thing that differentiates them is the region that they’re found in.
You apparently have never come across a Grizzly in the tundra... All of the linemen carry .45s and .44s for a reason.