However, there is no question that where large predators are present, ecosystems are healthier, more resilient, more complete than where the predators are absent. Huge, unchecked populations of elk, deer and bison had caused dramatic changes in the park's vegetation, and the hard winter of 1988-89 resulted in the starvation of thousands of these animals. Many other factors, including weather, disease, food supply and other predators, play into that balance. But wolves do positively influence prey populations in many ways some of which wildlife biologists do not yet fully understand. Similarly, it is an oversimplification to state that wolves exert a Darwinian influence over their prey by culling only the oldest, sickest and weakest animals from a herd.
Wolves are opportunistic, and they feed on healthy animals including young ones when they can.
Nevertheless, over the long term and in conjunction with the other factors mentioned above, wolves undoubtedly play an important role in the evolutionary process. Not only do wolves and other predators influence the health and genetic make-up of their prey, but over time prey species in turn influence the attributes of the predators that feed upon them. Because wolves and other predators reside at the top of the food chain, they serve as indicator species for the health of an ecosystem as a whole. Protection of areas large enough to support wolf populations results in the preservation of many other species as well. When we preserve this valuable biological diversity, we retain environments in which we may continue learning about natural process in all their wonderful complexity.