There aren't many natural predators left. The deer at Long Island only have people as a predator. When there were wolves there, they kept the deer population down. It is also very interesting how a wolf chooses its prey. People observing wolves have noticed that before a wolf attacks an animal, it locks eyes with its victim and then either kills its prey or lets it go.
Some animals give themselves up to the wolf, perhaps as a means of helping the rest of the pack.
Frequently wolves 'test' a herd by making it run. The wolves then kill and eat the weak members of a herd which actually benefits the herd because they aren't as vulnerable. Farmers and ranchers, however, have complained about wolves killing their livestock for years and believe that these complaints justify the extermination of the wolf. Wolves, in actuality, don't tend to kill farm animals. When they do it is usually the result of extreme hunger.