The ecosystem in Yellowstone National Park involves multiple predators competing for food. A classic grizzly versus wolf encounter just happened when a wolf tried to steal a meal from a sleeping grizzly.
Wyoming Game and Fish have trail cams all round the state. Not that long ago they placed one near a wolf den. They believed the pack would return at some point and their video proves they were correct.
It's not exactly breaking news that wolves and elk are natural adversaries. But, it's not everyday where you get to see video of their conflict. That's exactly what happened recently at Yellowstone National Park.