Wolf Species

The Gray Wolf

The Gray Wolf

Critically endangered Red Wolf

The Red Wolf

Mexican wolf

The Mexican Wolf (Grey Wolf subspecies)

Artic Wolf

The Arctic Wolf (Grey Wolf subspecies)

There are two species of wolves in North America:

There are two species of wolves in North America: the gray wolf (Canis lupus) and the red wolf (Canis rufus). The critically endangered red wolf is limited in its current range to a small portion of coastal North Carolina, but once roamed throughout the Southeast and much of the Eastern and South-central United States and north into Eastern Canada. With about 100 red wolves living in the wild, it is one of the world’s most endangered canids and is on the International Union for Conservation of Nature’s Red List of Threatened Species. Scientists are divided over whether another wolf, known as the eastern wolf, is a separate species (Canis lycaon) or another gray wolf subspecies (Canis lupus lycaon).

In North America, the gray wolf ranges across the U.S. Northern Rockies, the Pacific Northwest and the Western Great Lakes region, and from the U.S./Canadian border north to the Artic (including Alaska and Greenland) and in a small region along the Arizona-New Mexico border, with very few wolves struggling to survive in Mexico.

Beyond North America, the gray wolf ranges throughout northern latitudes inhabiting much of Eurasia, from Spain and Portugal to Scandinavia, the Alps and Eastern Europe and from the Middle East and the Indian subcontinent north across the former Soviet Union, China, and Mongolia. Gray wolves are residents of the world, and in many ways they are basically the same.


At one time, at least 24 subspecies of the wolf were recognized in North America, based on regional variations in overall size, color, and skull configuration. However, wolves travel great distances, which can result in interbreeding between subspecies often blurring the distinction between types. Common names such as eastern timber wolf and Rocky Mountain wolf describe geographic origin more than distinguishing physical characteristics. All gray wolves are much more similar than they are distinct.

Current classification divides North American gray wolves into four to six subspecies. The southernmost and smallest of these subspecies, the Mexican wolf (Canis lupus baileyi) is the most rare and critically endangered subspecies of gray wolf, with fewer than 100 animals surviving in Arizona, New Mexico and Mexico. The Mexican Wolf or “lobo” continues to receive federal Endangered Species protections, though they have been given the unfortunate designation of “Nonessential, Experimental.” This designation allows for what the U.S. Fish and Wildlife Service (FWS) refers to as “increased management flexibility.”

The Arctic wolf (Canis lupus arctos), resides in North America’s northernmost latitudes. Notwithstanding the debate over the eastern wolf, the other two subspecies currently recognized, which account for most of the wolves in the United States and Canada, are the Great Plains wolf (Canis lupus nubilis) and the Rocky Mountain Wolf (Canis lupus occidentalis).

What is a Pack


A Pack is a Family

Wolves are highly social animals that live in family groups, also referred to as packs. A family of wolves can consist of only parents and a few offspring, or it can be large and extended, including aunts and uncles, siblings, grandparents, and even adoptees.

The most basic form of a wolf pack consists of a bonded pair, known as the breeding pair or alphas. These are the leaders of the family and their bond can last a lifetime. The vast majority of the time, only the breeding pair within a pack reproduces. Breeding occurs early every year, in late winter. After a two-month or 63 day gestation period, pups are born underground in a den. The timing of this breeding cycle is such that pups are born at a time of year that will give them the best chance of survival with much of spring and all of summer and fall ahead of them to develop into nearly full grown wolves capable of surviving the next winter.

Pack size varies depending on geographic location and season, as well as prey size and availability. Small packs may consist of only two wolves, while larger packs can have more than twenty.

Physical Characteristics

 An average-size North American male gray wolf weighs from 70 to 130 pounds, stands 26 to 36 inches at the shoulders, and stretches five to six feet from nose to the tip of the tail. Females are about 20 percent smaller. The smaller Mexican wolf weighs 50 to 80 pounds. The coat or fur of a gray wolf can be many shades of gray, tan, brown, rusty red, cream, buff, and solid black or white. Arctic gray wolves tend to be creamy white and blend in better in landscapes dominated by snow and ice.

 The fur of a gray wolf consists of two layers: the outer guard hairs shed water and provide the markings, while the dense undercoat provides insulation. A wolf can curl up in the snow and sleep in temperatures of minus 50° Fahrenheit (minus 45° Celsius).

 Wolves roam over large territories and are built for distance running. Their chest is narrow, which makes forging through deep snow easier. Their legs are long and closely set together at the front, so that the rear paws follow the front paws in the same track. Their paws are large, almost the size of an adult human hand, which allows for easier travel across snow and other terrain

 As befits top-level carnivores, wolves have large teeth, and jaws with a bite force of 1,500 pounds per square inch, capable of crushing the thighbone of a moose.

Timeline & Maps

The Trail of the Wolf

History of Wolves in North America

  • 1870 to 1877

    Wolf Extermination Peaks.  In addition to ongoing state-by- state bounty programs, the federal government employs bounty hunters to eradicate wolves. During this period, as many as 100,000 wolves are killed each year.
  • 1914

    Wolf eradication campaign begins. The U.S. government approves destroying all species “injurious to agriculture” in the West. Yellowstone National Park begins a wolf eradication campaign.
  • 1926

    Park rangers shoot two wolf pups, the last two wolves in Yellowstone.
  • 1935 to 1968

    Yellowstone rangers shoot, trap, and export elk and other prey species that are now overpopulating and overgrazing the park.
  • 1944

Aldo Leopold, pioneer of American conservation, recommends bringing wolves back to Yellowstone.
  • 1974

    The gray wolf is protected by Congress under the Endangered Species Act, and the Rocky Mountain wolf recovery team is established.
  • 1987

    The U.S. Fish and Wildlife Service approves the Northern Rocky Mountain Wolf Recovery Plan.
  • 1995 to 1996

    After extensive public input, including testimony from more than 160,000 people, and based on the wolf recovery plan, 66 wolves from Canada are released into Yellowstone and Central Idaho.
  • 2005

    A federal mandate allows livestock owners in Montana and Idaho, with no permit required, to kill wolves threatening their livestock. State and tribal agencies can also kill wolves to protect their elk and deer herds.
  • 2007

    The U.S. Fish and Wildlife Service proposes removing 
the northern Rocky Mountain wolf population from the endangered species list. Three months later, the Service receives a letter from 247 independent scientists opposing the proposal and stating that the wolf population is too small to maintain long-term genetic viability.
  • 2008 to 2010

    The U.S. Fish and Wildlife Service removes wolves from the endangered species list twice, only to be overturned twice by a federal court upholding the Endangered Species Act. Wolves are hunted by the public in Idaho and Montana while court cases are pending.
  • 2011

    Via a rider attached to the federal budget, Congress removes wolves from endangered species protection in the Northern Rockies. A lone wolf, known as OR-7, crosses from Oregon into California, the first in more than 80 years.
  • 2012

    In one year, nearly 50 percent of Idaho’s wolves have been killed. Wyoming announces a shoot-on-sight policy in more than 80 percent of the state, any time of year, no license required. Montana triples its hunting quota and introduces a wolf-trapping season.
  • 2013

    In June of 2013, the agency has proposed to remove the gray wolf from the list of threatened and endangered species.  Many organizations hotly contest this proposal, claiming recovery is not complete and the delisting is premature.
  • 2014

    Idaho creates its Wolf Control Board on behalf of ranchers and hunters. For five years, the bill annually appropriates roughly $620,000 to kill wolves from general tax dollars, the Idaho Fish and Game and the livestock industry. The first wolf to reach the Grand Canyon in over 70 years, after traveling more than 750 miles, is shot by a coyote hunter claiming he misidentified the radio-collared wolf for a coyote. The McKittrick Policy, a controversial loophole in the ESA, protects those who kill an endangered species, but claim misidentification. Federal courts reinstate ESA protections for wolves in Wyoming, Michigan, Wisconsin and Minnesota.
  • 2015

    On Capitol Hill, legislation is introduced to remove ESA protections again for wolves in WY, MI, WI, and MN. Two referendums in MI show that the public (through overwhelming majority) do not want wolves to be hunted, but state legislators pass a third law that negated the referendums and the will of the people. Twenty years since reintroduction, the “Shasta pack,” becomes the first family of wolves in California to produce a litter in more than 90 years.
  • 2016

    In Oregon, polling shows overwhelming public support for wolves. Montana hunters continue to kill the wolves of Yellowstone National Park when they step outside of the park. The killing of the Profanity Peak pack on public lands, to appease a private livestock producer, signals a step backward for wolf recovery in the state of Washington. Director Dan Ashe of the U.S. Fish and Wildlife Service issues new regulations that grant greater protections for wolves and other predators on 73 million acres of Alaska’s national wildlife refuges.
  • 2017

    The federal government, under a new administration, reverses the protections issued for wolves and other predators on 73 million acres of Alaska’s national wildlife refuges. A wolf-baiting proposal in Idaho is shelved due to public outrage. The McKittrick Policy, known as the “I thought it was a coyote rule,” is overturned by a lawsuit brought on by conservation groups. A court decision opens wolf hunting once again in Wyoming. A well-known and loved wolf, White Lady, is poached inside Yellowstone National Park.


days of gestation before pups are born
one pound is what a pup weighs at birth
weeks pups' ears open and hearing develops
weeks until eyes open and pups can see
weeks after birth is when pups begin to wean
average lifespan of a wild wolf that survives the first year
pounds is how much meat a hungry wolf can eat in one meal
pounds is the weight of a very large female wolf
the number of teeth wolves have
pounds is the weight of a very large male wolf
miles in a day wolves are capable of traveling
miles wolves have wandered in search of a mate or a pack