The gray wolf (Canis lupus) is a member of the Canidae family and also known as the Arctic wolf, common wolf, Mexican wolf, Plains wolf, timber wolf, Tundra wolf. The species was the world's most widely distributed mammal but has become extinct in much of Western Europe, in Mexico and much of the USA. Wolves occur primarily but not exclusively in wilderness and remote areas. Their original worldwide range has been reduced by about one-third by deliberate persecution due to depredation on livestock and fear of attacks on humans. Although the species still faces some threats, it is relatively widespread with a stable population trend and has therefore been assessed as Least Concern by IUCN since 2004.
Canis lupus excludes the domestic dog and the dingo.
Though once abundant over much of Eurasia, North Africa and North America, the gray wolf inhabits a reduced portion of its former range due to widespread destruction of its territory, human encroachment, and the resulting human-wolf encounters that sparked broad extirpation. Today, wolves are protected in some areas, hunted for sport in others, or may be subject to population control or extermination as threats to livestock, people, and pets.
Gray wolves are social predators that live in nuclear families consisting of a mated pair, their offspring and, occasionally, adopted immature wolves. They primarily feed on ungulates, which they hunt by wearing them down in short chases. Gray wolves are typically apex predators throughout their range, with only humans and tigers posing significant threats to them.
Apex predators (also known as alpha-, super-, top- or top-level predators) are predators with no predators of their own, residing at the top of their food chain. Zoologists define predation as the killing and consumption of another organism (which generally excludes parasites and most bacteria). In this context, "apex predator" is usually defined in terms of trophic dynamics. Apex predator species occupy the highest trophic level(s) and have a crucial role in maintaining the health of their ecosystems. One study of marine food webs defined apex predators as greater than trophic level four. The apex predator concept is commonly applied in wildlife management, conservation, and ecotourism.
Food chains are often far shorter on land, with the top of the food chain limited to the third trophic level, as where such predators as the big cats, crocodilians, hyenas, wolves, or giant constrictor snakes prey upon large herbivores. Apex predators need not be hypercarnivores. For example, grizzly bears and humans are each apex predators and are omnivores. A dog, more carnivorous than either humans or most bears, is usually more of a scavenger than a predator, but as an occasional killer of livestock or wildlife and a participant in some human hunts it qualifies as a superpredator in much of its extensive range; this is especially true of giant molosser breeds that have for their size the strength, power, agility, speed, cunning, intelligence, and aggression characteristic of wolves, bears, big cats, and hyenas but unlike those other predators do not ordinarily prey on humans. In this sense, an apex predator can be defined as being too difficult to kill for them to be a regular source of food for other predators. Some animals may be superpredators in some environments but not others, such as domestic dogs and cats, both of which can ravage ecosystems (see Stephens Island Wren).