A female black bear.
Although I took this shot with a telephoto lens I was relatively close to it only about 50 yards! However there was a ravine with a stream running through it between me and the bear and I was standing next to my car with the door open! About 100yds to the left of this bear was a male, making its way towards this bear in order to mate. Shortly after I took this shot a Park Ranger appeared and ushered everyone back into their vehicles.
Lamar Valley, Yellowstone National Park, Wyoming