The gray wolf also known as the wolf, is the largest extant wild member of the Canidae family. 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.
Even so, the gray wolf is regarded as being of least concern for extinction by the International Union for Conservation of Nature, when the entire gray wolf population is considered as a whole. 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.
This primitive wolf closely resembled the modern southern wolf populations of the Arabian Peninsula and South Asia, which were once distributed in Europe in the early Quaternary glaciation until about 500,000 years ago. mosbachensis evolved in the direction of Canis lupus, and recolonised North America in the late Rancholabrean era. There, a larger canid species called Canis dirus was already established, but it became extinct 8,000 years ago after the large prey it relied on was wiped out. Competition with the newly arrived gray wolves for the smaller and swifter prey that survived may have contributed to its decline. With the extinction of dire wolves, gray wolves became the only large and widespread canid species left.
Gray wolves are slender, powerfully built animals with large, deeply descending ribcages and sloping backs. Their abdomens are pulled in, and their necks heavily muscled. Their limbs are long and robust, with comparatively small paws. The front paws have five toes each, while the back paws have four. The forelimbs are seemingly pressed into the chest, with the elbows pointed inward, and the feet outward. Females tend to have narrower muzzles and foreheads, thinner necks, slightly shorter legs and less massive shoulders than males. Wolves are very strong for their size, possessing sufficient strength to turn over a frozen horse or moose carcass.
Although wolf packs do cooperate strategically in bringing down prey, they do not do so as frequently or as effectively as lionesses do; unlike lions, wolves rarely remain with their pack for more than two years, thus they have less time to learn how to hunt cooperatively. Contrary to lion prides, food acquisition per wolf decreases with pack size. Overall, single wolves or mated pairs typically have higher success rates in hunting than do large packs. Single wolves have occasionally been observed to kill large prey such as moose, bison and muskoxen unaided. When hunting, wolves will attempt to conceal themselves as they approach their prey. With ungulate herds, they then either attempt to break up the herd, or isolate one or two animals from it. If the targeted animal stands its ground, the wolves either ignore it, or try to intimidate it into running. When chasing small prey, wolves will attempt to catch up with their prey as soon as possible.