In October of 1998, the howling of wolves could be heard in Grand Teton National Park for the first time in over fifty years. Two years after being reintroduced to Yellowstone, wolves began expanding their range south to encompass the sagebrush flats, forested hillsides, and river bottoms of Grand Teton National Park and the valley of Jackson Hole. Their return represents the restoration of an important part of this ecosystem.

Although their present distribution is limited to Canada, Alaska, and a few isolated areas in the northern United States, wolves once roamed the tundra, forests, and high plains of North America from coast to coast. By 1930, human activities, including extensive settlement, unregulated harvest, and organized predator control programs, had pushed the gray wolf to the brink of extinction in the United States. The last known wild wolf in the Yellowstone area was killed in the 1940s.

In 1987, the United States Fish and Wildlife Service recommended establishing three core wolf recovery areas in the Northern Rocky Mountain region: northwestern Montana, central Idaho, and Yellowstone. Biologists suggested allowing wolf populations to recover naturally in northwestern Montana while reintroducing wolves in central Idaho and Yellowstone.

In accordance with this plan, wolves captured in Canada were transported to the U.S. and released in central Idaho and Yellowstone National Park in 1995 and 1996.

Ecology
The gray wolf is a critical player in the Greater Yellowstone Ecosystem, which encompasses Yellowstone and Grand Teton National Parks and surrounding National Forests. Wolves are highly efficient and selective predators, preying on young, old, weak, and sick animals. By culling the herds of their prey species in this manner, wolves are important agents of natural selection, encouraging survivorship of those animals best suited to their environment—the fastest, strongest, and healthiest.

In the Greater Yellowstone Ecosystem, wolves usually prey on elk, although they will occasionally take moose, bison, pronghorn, bighorn sheep, and beavers. Wolf populations are naturally regulated by prey availability, which prevents decimation of prey species populations.

Although wolves do make surplus kills when convenient, the carcasses do not go to waste. They are either cached for later consumption or left for scavengers, including coyotes, ravens, magpies, golden and bald eagles, crows, bears, wolverines, fishers, mountain lions, and lynx.

Wolf Biology
The gray or timber wolf, Canis lupus, is the largest wild canid in existence, ranging from 60 to 175 pounds. Despite its common name the gray wolf may be white, silver/gray, or black in color. Wolves have been clocked at speeds in excess of thirty miles per hour and have been known to travel over a hundred miles in a day, although travels are more often ten or twenty miles per day. Wolves may live up to fifteen years in the wild.

Wolves are highly social animals, functioning primarily in packs. The social structure of the pack is based on a breeding pair comprised of an alpha male and female, followed by a hierarchy consisting of betas (second rank, males and/or females), subordinates, pups, and occasional omegas (outcasts, generally recipients of aggressive behavior from other pack members).

Because only the alpha pair breeds, subordinate wolves of reproductive age must disperse from their packs and form new associations in order to breed. Pack size is ultimately determined by hunting efficiency, which in turn depends on the size, type, and density of prey species available. Wolf packs average five to ten members.

Wolf packs defend home ranges of up to several hundred square miles. During the spring denning season, wolves are especially aggressive in defending core territories around their den sites. In the Greater Yellowstone Ecosystem, wolves generally breed in February and give birth in late April, after a gestation period of about 63 days. The alpha female usually remains at the den site with the pups, while the alpha male and other pack members bring food back to the den. When pups reach approximately two months of age, they are moved to an outdoor nursery referred to as a rendezvous site. By October, pups are usually traveling and hunting with the rest of their pack.

Eradication History
Wolves have long been the target of aggressive eradication efforts by humans. In 1630, the Colony of Massachusetts enacted the first bounty on wolves in what is now the United States. Wolves were effectively eliminated from the eastern United States by the end of the eighteenth century. With settlers' westward expansion, populations of predator and prey species were greatly reduced due to human development and unregulated harvest.

The decline in wild prey populations, especially bison, led many people to believe that wolves posed an unacceptable threat to domestic livestock. These beliefs fueled government-sanctioned, bounty-driven efforts to destroy the wolf in the west. From approximately 1850 through 1930, thousands of wolves were trapped, shot, and poisoned each year in the western U.S.

Government hunters destroyed the last known wolf in the Yellowstone area in the 1940s. By 1930, wolves were virtually absent from the contiguous U.S., except Minnesota and remote areas of northwestern Montana. Sizeable wolf populations remained in Canada and Alaska.

Recovery
1973 marked the passing of the federal Endangered Species Act (ESA), a pivotal event in the history of wildlife preservation. Under the ESA, the gray wolf is listed as endangered throughout the contiguous United States except Minnesota, where it is listed as threatened. The ESA defines an endangered species as one "in danger of extinction throughout all or a significant part of its range" and a threatened species as one "likely to become endangered" in the foreseeable future.

The Endangered Species Act requires the U.S. Fish and Wildlife Service (FWS) to create recovery plans for all listed species. In 1987, the FWS published a recovery plan for the gray wolf in the Northern Rockies, which recommended establishing three gray wolf populations, in northwestern Montana, central Idaho, and Yellowstone, respectively. Biologists predicted that wolves from Canada would naturally recolonize northwestern Montana. However, because central Idaho and Yellowstone were isolated from existing wolf populations, biologists determined that it was impractical to expect natural recolonization of these areas in the near future. Therefore, the Fish and Wildlife Service recommended reintroducing wolves into central Idaho and Yellowstone, while encouraging natural wolf recovery in northwestern Montana.

In 1995, wolves captured in Canada were transported to the U.S. and released in central Idaho and Yellowstone National Park. Because the central Idaho and Yellowstone area wolves are reintroduced populations, they are defined as "experimental" according to the Endangered Species Act. This designation allows more flexibility in managing these populations than is normally allowed for populations of endangered species.

Delisting/Reclassification of the Gray Wolf in the Northern Rocky Mountains
The minimum criteria for removal of the gray wolf from the endangered species list requires the establishment of ten breeding pairs, about 100 wolves, in each of three northern Rocky Mountain population areas (Yellowstone, central Idaho, and northwestern Montana) for three consecutive years. As a prerequisite for delisting from federal protection, the individual states within the recovery area must establish wolf management plans approved by the FWS. These state plans could allow for wolves to be managed in a manner similar to that in which individual states currently manage other large predators, such as bears and mountain lions.

Wildlife managers predicted that recovery goals for the northern Rocky Mountain region would be achieved by the year 2002 or 2003, andit seems that the restoration program is on track. In 1998, there were nine breeding pairs/packs in the Yellowstone area, ten in central Idaho, and seven in northwestern Montana.

Your Park Visit
As with all wildlife, it is smart to keep your distance from wolves in order to avoid disturbing the animals or endangering yourself. Many wild animals will attack people if provoked. However, according to wolf expert L. David Mech, there has never been a documented case of a healthy, wild wolf killing or seriously injuring a human in the Western Hemisphere.

There have been five documented cases of pets being killed by wolves in the Yellowstone area since the reintroduction, and rates of wolf attacks on pets have been similarly low in other areas inhabited by wolves. Grand Teton National Park regulations restrict pets to areas open to motorized vehicles, and require that pets be restrained on a leash at all times.