Thanks Bill

As for controling the population, I always thought it was the prey species that controled it. Take for example yotes and rabbits. It's the fluctuating rabbit population thathas the greatest effect onhow many yotes can survive - not enough rabbits the yote population will drop (it's cyclical). All the course I ever took focused on the pred/prey relationships, not pred/pred relationships. I do see that there can be some correlation with that more predators can lower the prey species more, but I don't necessarily buy into the larger pred dispacing the others (like mentioned by a few others - AK, Yellowstone, etc - different ecosystems, but correlations can be used).