Wolf

I

INTRODUCTION

Timber Wolf

In marked contrast to their fond feelings for the domesticated dog, humans have historically feared, hated, and persecuted its ancestor, the timber wolf, also known as the gray wolf, Canis lupus. Indeed, many of the qualities that people value in the dog—its loyalty, its loving nature, its readiness to submit to authority, and its ability to learn—derive directly from the cooperative and subtle behavior of the wolf interacting with others in its pack.

Jim Brandenburg/Minden Pictures

Wolf, a large carnivore related to the jackal and domestic dog. Wolves are known for their keen intelligence, skilled hunting, and highly organized social structure.

There are two species and one subspecies of wolves. The gray wolf is native to the Northern Hemisphere. Gray wolves that live in the treeless plains of the Arctic are called Arctic wolves, and those found in wooded, subarctic regions are known as timber wolves or eastern timber wolves. The Mexican gray wolf, a subspecies of the gray wolf, is native to Arizona, New Mexico, Texas, and Mexico. The red wolf is native to the southeastern United States.

II

PHYSICAL CHARACTERISTICS OF THE WOLF

Gray Wolf

The gray wolf, also called the timber wolf, inhabits mountains, forests, taiga, plains, and tundra across northern North America, Europe, and Asia. One of at least 36 species belonging to the family Canidae, which includes the coyote, jackal, fox, and domestic dog, the wolf is characterized by powerful teeth, a bushy tail, and round pupils, and lives and hunts in packs. The family Canidae is believed to have originated in North America 55 million to 38 million years ago during the Eocene Epoch.

F. Schneidermeyer/Oxford Scientific Films/BBC Natural History Sound Library. All rights reserved.

Wolves have strong jaws, powerful legs, and bushy tails. Certain features of the skull distinguish them from domestic dogs, some breeds of which they otherwise resemble. The shaggy coat of most gray wolves is smoky gray, but it may have a brownish or reddish tinge. The chest and abdomen are usually white, with black patches on the backs and sides. Some gray wolf populations are pure black or pure white. An adult gray wolf stands about 90 cm (about 3 ft) high at the shoulder, measures 120 cm (4 ft) in length excluding the tail, and weighs 31 to 54 kg (68 to 120 lb). Females are smaller than males, and southern gray wolves are smaller than those in the north.

III

HABITAT AND HUNTING

The wolf was originally among the world’s most widely distributed mammals. Historically it ranged from Canada to Mexico in North America, throughout most countries in Europe, and in northern Russia, parts of the Middle East, China, India, and Nepal. Highly adaptable animals, wolves are at home in a diverse range of habitats, from prairies and Arctic tundra to forests, lowlands, and all but the highest mountains. They also thrive in a variety of climates and may settle in areas inhabited by people. Choice of location is mainly directed by the availability of prey. Wolf packs establish and defend territory that can range in size from 26 to 2,590 sq km (10 to 1,000 sq mi), depending on the species.

Gray wolves will travel long distances in pursuit of prey, sometimes as far as 48 km (30 mi) in one day. The gray wolf can travel at up to 56 km (35 mi) per hour but is comfortable trotting at 8 km (5 mi) per hour. Particularly during the winter, large packs of up to 24 members will form to hunt deer, caribou, moose, and other large herbivores. Members of these packs cooperate to drive and ambush prey. They will usually select the weak, old, or very young animals for easier capture. Hunts can begin in the early evening and continue until morning.

Wolves also prey on rabbits, rodents, and birds. A wolf may consume up to 8 kg (18 lb) of meat at one time. When no live prey can be found, they will feed on carrion (decaying flesh of dead animals), berries, and invertebrates. There are few if any documented cases of a healthy wild wolf attacking a human without provocation.

IV

SOCIAL STRUCTURE AND BEHAVIOR OF WOLVES

Most wolves live in packs. Parents, their young, and nonbreeding adults make up a basic pack, which generally consists of eight or fewer members. Within each pack, one hierarchy exists for females and another for males. The pack leader is called the alpha male, and his mate is the alpha female. These two animals occupy the dominant rank in their respective hierarchies and are usually the oldest members of the pack. The alpha maintains its status by winning fights, and changes to lower-ranking positions are infrequent. Young pups remain somewhat outside the social hierarchies until they reach maturity.

Wolves communicate with visual signals, scent, and sound. They also exhibit behavioral patterns that show dominance over or submission to one another. Body language makes it clear which animal has higher rank. Tail position and bared teeth convey various moods and attitudes, including submission, fear, and a readiness to attack. Scent signals are also used in communication. A pack establishes and defends its territory by marking it with urine and feces. Communal howling is an important social activity and may serve to assemble pack members, communicate with other packs, maintain territorial claims, or express pleasure. It is also used as a hunting cry, frequently sounded at dusk in preparation for the chase.

V

REPRODUCTION AND LIFE SPAN

It is believed that wolves mate for life. The alpha pair has exclusive breeding rights during mating season, which occurs during the spring. After a gestation of about two months, a litter of blackish-brown pups is born. Average litter size is 6 but can be as large as 14. For the first six weeks, the pups remain in the den, or lair, which may be a cave, a hollow tree trunk, or a thicket. At nine days old the pups open their eyes. After one month, they are gradually weaned and then fed regurgitated food by adult pack members. At 3 months they begin learning how to hunt, and by 18 months they are fully grown. Females reach maturity at two years of age, and males at three. The family remains together for at least two years, even when the mother breeds in successive years. Wolves generally live eight to ten years in the wild.

VI

CONSERVATION HISTORY

By the early 20th century, wolf populations had been significantly reduced in many areas, and the animal has neared extinction in Western Europe, Mexico, and regions of the United States. Under the United States Endangered Species Act of 1973, the gray wolf was listed as a threatened species in Minnesota and as endangered elsewhere in the United States except Alaska. In 1995 and 1996 the United States Fish and Wildlife Service (USFWS) reintroduced gray wolves into Yellowstone National Park and the Sawtooth Mountain region of central Idaho. These reintroductions have been highly successful, and in early 2008 the USFWS announced that it would remove wolves in the northern Rocky Mountain region from the federal list of endangered and threatened species. In early 2007, wolves in the western Great Lakes region were removed from the list. Gray wolves outside these areas remain protected.

The Mexican gray wolf was nearly extinct by the 1970s and listed as endangered in 1976. A successful captive-breeding program was initiated and in 1998 it was reintroduced to areas of Arizona and New Mexico.

VII

CULTURAL REFERENCES TO THE WOLF

Wolves appear in the stories, legends, and myths of many cultures around the world. Romulus, the legendary founder of Rome, and his twin brother Remus are said to have been suckled by a she-wolf. The werewolf myth dates to ancient Greece, and the fairy tale “Little Red Riding Hood” tells of an encounter between a girl and a wolf. In the Jungle Books written by Rudyard Kipling, the boy Mowgli is raised by a wolf in India. In Norse mythology the giant, terrifying wolf Fenrir is the eldest son of Loki and a giantess.

VIII

RED WOLF

Red Wolf

The red wolf, Canis rufus, is smaller than its close relative, the gray wolf. Virtually extinct in the wild, the United States Fish and Wildlife Service is breeding red wolves in captivity. They have had mixed success when the captive-bred red wolves were released into two wilderness sites within their native habitat in the southeastern United States. Some wolves were able to thrive while others died.

Tim Davis/Photo Researchers, Inc.

The red wolf is smaller than the gray wolf. An adult red wolf stands about 65 cm (about 2 ft) high at the shoulder, measures 100 to 130 cm (3 to 4 ft) in length excluding the tail, and weighs 20 to 36 kg (45 to 80 lb). It has long legs and ears and its head is not as wide as that of the gray wolf. The coat of red wolves varies in color from light tan to black with reddish head, ears, and legs. Scientists have debated whether the red wolf is a subspecies of the gray wolf, a separate species, or a cross between the coyote and the gray wolf.

Like other wolves, the red wolf is territorial, mostly nocturnal, highly social, and an efficient hunter. It frequently preys on white-tailed deer and raccoons. Red wolves usually live in pairs or small family groups, and they establish a territory that ranges in size from 26 to 260 sq km (10 to 100 sq mi). Pack size and territorial area are generally smaller than those of gray wolves.

Red wolves were historically hunted, trapped, and poisoned by North American settlers, who viewed them as a threat. In the early 20th century red wolves were subject to predator control programs due to fears that they caused extensive cattle losses. As the number of red wolves declined, mating patterns were disrupted and they began to interbreed with coyotes. Red wolf habitat has also been destroyed due to logging, mineral exploration, and land clearing.

The red wolf was first protected as an endangered species in 1967 under a law that preceded the Endangered Species Act. In 1973 the USFWS initiated a captive-breeding program for the species. By 1980 red wolves were considered extinct in the wild.

Captive red wolf pairs produced their first litters at the Point Defiance Zoo and Aquarium in Tacoma, Washington, in 1977. The captive red wolf population has since increased and in 1987 four pairs of red wolves were reintroduced to the Alligator River National Wildlife Refuge in northeastern North Carolina. In 1991 and 1992 additional red wolves were reintroduced to Great Smoky Mountains National Park. These efforts have met with limited success, and the red wolf remains a protected species.

Scientific classification: The wolf belongs to the family Canidae. The gray wolf is classified as Canis lupus, the Mexican gray wolf as Canis lupus baileyi, and the red wolf as Canis rufus.

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