Historic Gray Wolf Range. Map: U.S. Fish and Wildlife Service
Wolves were once abundant and distributed over much of North America, Eurasia, and the Middle East.
Native Americans were awed by the power and stealth of the wolf, while European settlers -- who brought over their folk tales of the "big bad wolf" -- feared the animal. This fear, combined with the belief that wolves caused widespread livestock losses, led to their near extinction in the lower 48 states in the early half of the 20th century.
The wolf is the ancestor of the domestic dog.
Wolves are currently protected under the Endangered Species Act of 1973 in the contiguous United States.
Gray Wolf Range, 1974. Map: U.S. Fish and Wildlife Service
Sixty-six wolves were reintroduced into Yellowstone National Park and the wilderness of central Idaho in 1995 and 1996. There are now enough wolves to warrant removal from the list of endangered species in the states of Montana, Idaho, and Wyoming.
Some 50 Mexican gray wolves have been reintroduced in Arizona and New Mexico from a captive population but are having trouble adapting to their new surroundings.
Worldwide, gray wolves are coming back due to research and public education efforts and can be found in several European countries such as Italy, Spain and France.
Gray Wolf Range, 2006. Map: U.S. Fish and Wildlife Service
The 66 wolves reintroduced into Yellowstone and central Idaho have developed into a population of about 1,000 in the Northern Rockies of Montana, Idaho, and Wyoming (this figure does not include this year's pups).
About 390 wolves have been killed by federal and state officials in "management actions" in the Northern Rockies since the wolves were reintroduced. An equal number were killed illegally.
There are about 4,000 wolves in Minnesota, Wisconsin, and Michigan.
At least 9,000 wolves can be found in Alaska, where they are not endangered.
Wolves roam freely in Yellowstone National Park
Wolves are social among their own kind, but typically avoid human contact and rarely pose a threat to human safety. In the past 100 years, there have been several published accounts of human injuries, but no fatalities, due to wolves.
Wolves indirectly support a wide variety of other animals. Ravens, foxes, wolverines, and vultures feed on the remains of animals killed by wolves. Wolves also help regulate the balance between hoofed animals, such as deer, and their food supply, making room for smaller plant-eaters, such as beaver.
After wolves leave their pack at two or three years of age, they search for their life-long mate and try to develop their own pack.
Wolf packs usually live within a specific territory, which typically ranges in size from 50 square miles to 1,000 square miles, depending on prey.
Livestock Killed by Yellowstone Wolves
Source: U.S. Fish and Wildlife Service
Wolves' social structure and pack behavior minimizes their need to scavenge for food or garbage from human sources.
Their primary need is for prey, which is most likely to be elk, deer, and moose.
Wolves communicate through howling, body language, and scent. Howling is used to assemble the pack, talk to other packs and to assert territorial claims.
Wolves use their faces and tails to indicate their emotion and status in the pack. A pack marks its territory using urine and feces.