A bunch of photographers were on wolf-watch in Yellowstone's Lamar Valley when a tourist drove up and said, "There's a couple of grizzlies mating down the road. Are you guys interested?" It looked like the start at LeMans as everybody scrambled for their cars Sure enough there were a couple of grizzlies, but instead of a mated pair, they were a couple of siblings that had just been kicked out by mom. The stayed around for quite awhile, giving us lots of chances for different behaviors as they wrestled and played. Grizzly cubs stayed with their mother until the start of the third spring, when she lets them know they are on their own and goes in search of a new mate.
From my ebook: Shooting Greater Yellowstone