Wolves are apex predators in whatever environment they inhabit. As such, no animal actively hunts them for food. However, the cougar and bear are capable of killing wolves, although the reverse is also true. Neither animal hunts the other, and they compete for food when their hunting ranges overlap. Wolves are such efficient hunters that they often replace the bear or cougar as the top predator in a region.
Wolves are carnivorous, meaning they eat the flesh of other animals, and they are adept at hunting their prey, including moose, deer, beaver, mountain goats and other creatures.
Wolves are also pack animals, meaning they do almost everything in a group, including hunting. One of the reasons that wolves are such formidable predators at the top of the food chain is that they are usually found in packs.
Generally, the alpha wolves, who are the leaders of the pack, also happen to be the best hunters and play an important role in protecting the pack's territory. This all contributes to wolf packs being infrequent victims of predators in the wild.
However, if a wolf is separated from the pack, it may be vulnerable to other animals in the wild. If other prey is not available, alpha wolves have been known to eat other wolves that are not as capable of defending themselves. Wolves may also be harmed when other animals, such as large elk, injure or kill them in self-defense.
After wolves die, plenty of animals eat them. Buzzards, ants, vultures and other carrion-eaters exclusive to the ecosystem the wolves inhabit feast on their remains. Although rare, bears and cougars eat wolves they manage to kill. Wolves travel in packs to minimize this. Nonetheless, most encounters occur when a wolf tries to take a carcass from another apex predator. Wolves are usually more successful in these endeavors because of their numbers, aggressiveness and superior endurance to other animals.
Although there are several types of wolves, the largest member of the species is the gray wolf. It is the one capable of hunting larger animals and establishing itself as the apex predator in any environment into which it's introduced. Of all the animals on earth that inhabit its possible ranges, humans and tigers are the only predators wolves cannot displace from the top of the food chain.