The US Fish and Wildlife Service maintains a website at GRAY WOLF.
DISCOVERY (95) - In March of 1995, 14 Canadian gray wolves have been released in three packs in Yellowstone National Park. The packs have stayed put and have had two litters.
US FISH AND WILDLIFE ARTICLE - Wolf packs territories range from 50 to 1,000 square miles, depending on food resources. The group consists of the dominant alpha pair, their offspring, and other non-breeding adults. Only the alpha female bears young. An average of six pups are born in early spring. For the first six weeks, the pups live in the den (sometimes with chambers and tunnels). By Fall, at near fully grown, the young start hunting with the adults. At one or two years of age, the young wolf will leave and try to form it’s own pack. At two or three, they will begin mating, sometimes for life.
Today, about 2,000 wolves exist in Minnesota, fewer than 20 on Lake Superior's Isle Royale, about 60 in Michigan's Upper Peninsula, 40 to 50 in Wisconsin, and about 65 in Montana. Numbers are low but unknown in Idaho and Washington, and an occasional individual is seen in Wyoming, North Dakota, and South Dakota. Populations fluctuate due to food availability and strife within packs.
The gray wolf is listed under the Endangered Species Act as a threatened species in Minnesota, and as an endangered species elsewhere in the lower 48 states. In Alaska, wolf populations number 5,900 to 7,200 and are not considered endangered or threatened. In 1994 the U.S. Fish and Wildlife Service began an effort to reintroduce gray wolves into Yellowstone and U.S. Forest Service lands in central Idaho. The Service had previously identified these areas as necessary for wolf recovery, as well northwest Montana, where wolf packs have already become established as wolves from Canada have expanded their range. Part of the reintroduction effort involves capturing a group of wolves from Alberta and British Columbia, Canada, and bringing them to the U.S. for the reintroduction. Under the Fish and Wildlife Service's plan for wolf recovery, reintroduction would begin in 1994 and last for 3 to 5 years. Wolf populations would be expected to recover by 2002, at which time the Fish and Wildlife Service would propose to remove the wolf from the list of endangered and threatened species.