Mexican Gray Wolf

Wolves are wild carnivore members of the dog family (Canidae). They are believed to be ancestors of the domestic dog, which evolved separately more than 20,000 years ago. Only two species of wolves remain today -- the Gray Wolf (Canis lupus) -- also called the Timber Wolf -- and the Red Wolf (Canis rufus).

The Gray Wolf is the best-known species and still inhabits some areas of the Northern Hemisphere. Some taxonomists contend there are as many as 30 subspecies of the Gray Wolf. One of these, the Mexican Wolf (Canis lupus baileyi) is the only wolf indigenous to the Southwestern Deserts.

The Red Wolf (C. rufus) is a smaller species almost extinct from the south-central United States. The extinct Dire Wolf (C. dirus), was half again as large as the modern Gray Wolf and was common in western North America during the Pleistocene, until about 10,000 years ago.

Range 

The Gray Wolf has a larger natural distribution than any other mammal except humans. It once ranged through all of North America from the Arctic Circle to central Mexico. But because of human persecution and habitat destruction it has been eliminated from much of its original range.In North America, the Gray Wolf is now found primarily in Canada and Alaska, with much smaller numbers in Minnesota. In 1995 wolves were reintroduced in wilderness areas of the northern Rocky Mountains. A small population of the sub-species Mexican Wolf once existed in higher elevations of the Sonoran and Chihuahuan deserts of Mexico but is now extinct in its native habitat.

Habitat

Wolves can live in a great variety of habitats, ranging from arctic tundra to forest and prairie, if adequate prey is present. They are absent from tropical forests, desert floors and the highest mountains.

Description

 The Gray Wolf looks much like a German Shepherd, but it has a broader skull and longer ears. It is also more bushy-tailed, long-nosed and long-legged. The Gray Wolf has a tendency to look lean and rangy somewhat like a coyote, but it is larger and carries its tail high rather than low.

Wolf size varies with geographic locality. Adults males range from about 5 to 6.5 feet, from their nose to tip of their tail. They stand from 36 to 40 inches high at the shoulders and weigh from 100 to 175 pounds. Females are slightly smaller than males, and Mexican Wolves tend to be smaller than their northern cousins. Coat colors vary from white to grizzled gray to brown or black.

Habits

Wolves usually travel in packs and establish territories ranging from 30 to more than 500 square miles. They define their ranges with scent markings and such vocalizations as growls, barks and their legendary howl.

In regions like the desert where typical prey is small, packs may consist of 7 or less, instead of 30 or more where prey is large. There is a clearly defined dominance hierarchy in the pack, the nucleus of which is the breeding (alpha) pair, who mate for life. Additional members include offspring and "helpers."

Wolves eat a wide variety of food, including small animals like mice and squirrels, large animals like deer and moose and sometimes, carrion and plant material. Animals killed are usually young, old, or otherwise impaired and weaker than others.

Wolves often prey on domestic animals because of their vulnerability, which has resulted in the wolf's persecution by poisoning, trapping, and shooting. Attacks on humans are rare and believed to occur only in isolated cases of famine or an epidemic among wolf populations.

Life Cycle

Only the alpha pair in each pack breed each year. This occurs between January (at low latitudes) and April (at higher latitudes). A litter of 6 to 7 pups is born blind after a gestation period of about 63 days. The pups are reared in a den composed of a natural hole or burrow. All members of the pack care for the pups, who are fed regurgitated meat after hunts.

Pups are weaned at about the fifth week and approach adult size by early winter. By autumn, because pups are now capable of traveling with the adults, the pack hunts as a unit throughout its territory. Juveniles remain with the pack until they reach sexual maturity at about two years, after which they may leave to search for a mate and establish new territories, or remain as helpers.

Mortality factors affecting wolves include persecution by humans, killing by other wolves, parasites, diseases, starvation and injuries by prey. Wolves probably don't live more than ten years in the wild.

Mexican Gray Wolf

The Mexican Wolf is the rarest, southernmost and most genetically distinct sub-species of the Gray Wolf in North America. It is also one of the smallest sub-species, reaching an overall length no greater than 4.5 feet and a height maximum of about 32 inches.

Until recent times, the Mexican Wolf ranged the Sonoran and Chihuahuan deserts from central Mexico to western Texas, southern New Mexico and central Arizona. By the the turn of the century, reduction of natural prey like deer and elk caused many wolves to begin attacking domestic livestock, which led to intensive efforts by government agencies and individuals to eradicate the Mexican Wolf.

These efforts were very successful, and by the 1950s, the Mexican Wolf had been eliminated from the wild. In 1976, the Mexican Gray Wolf was declared an endangered species and has remained so ever since. Less than 200 Mexican Wolves now survive in zoos and museums due to successful captive breeding programs.

In March 1997, the U.S. Secretary of the Interior authorized the U.S. Fish and Wildlife Service to begin reintroducing Mexican Wolves into the Blue Range area of Arizona. The overall objective of this program is to reestablish 100 Mexican Wolves in the Apache and Gila National Forests of of Arizona and New Mexico by 2005.