I've have seen that with my own two eyes. I was 12 years old and on my first elk hunt, opening morning. We were hunting a deep caynon and I was ahead of my dad probally 50 yards and saw a herd of elk crossing in front of me about 150 yds slowly walking. I signaled my dad over and before he made it, there was a spike bull towards the back of the herd my dad froze and watched.(the area was spike only)I was waiting for a shot letting elk pass and lone behold I knowtice what I thought was a very short calf elk following a cow at the back of the herd by the spike.
I was getting ready to shoot at the spike and the herd busted out in a dead run with that little calf I knowticed behind the cow chasing and swiping at the herd.(LION) The whole time which was probally 1 minute that i was watching the herd the lion was walking right behind those elk and the elk never even knew it. Anyways the pic reminded me of that and what a rare sighting it truley was.