Imagine what you would do in this situation. You're a deer (I realize that's a reach) and you're being chased by a coyote. What do you do? If you're in Yellowstone National Park, you hide in a nearby bison herd which is exactly what just happened as a new video shows.
If you hike Yellowstone National Park any time of year, there is a chance you will encounter wildlife. But, it's not common at all to come upon a red fox like this hiker recently did inside of the park.
I have to confess that I can always be entertained by a good trail cam video. There are none better than the ones shared by Wyoming Game and Fish. I have found a best-of video they just dropped on their YouTube channel.