The Grey Wolf is very important to the food chain, as, as it is at top it controls the populations of the caribou, deer and moose. The wolves take the sick and weak animals such as the older ones (they wouldn�t bother with a healthy moose that stands its ground), making sure that the strongest of the herds survive, and so making the herd stronger through this type of selective breeding.

A good example of when this was not the case, was when in Yellowstone National Park. There were no wolves there, and the populations of these herds multiplied extensively, ended up over grazing the land, creating a food shortage, and many of these animals died from this. The wolves have been reintroduced here and the balance is even again.