The gray wolf, also known as the timber wolf, has endured a long and tumultuous relationship with humans. They thrived prior to the 20th century in the U.S., revered by most Native American nations. Wolf populations shrank to near extermination in the early and mid 20th century in the U.S. due to eradication efforts by settlers who found them a threat to livestock. Efforts to bring back the gray wolf began in 1973 with the Endangered Species Act (ESA) and their numbers continue to climb today.
The gray wolf once ranged from Canada to Mexico and from the Pacific coast to the Atlantic with the exception of the Southeastern U.S. (home of the red wolf, Canis rufus). It is now found throughout Canada, Alaska, and a number of locations in the Midwestern U.S. including Michigan, Wisconsin, Minnesota, and Yellowstone National Park in Wyoming, home of a recently re-introduced group. On a global scale, gray wolf populations are recovering due to research and public education efforts. They can now also be found in several countries in Europe. Highly adaptive, gray wolves have inhabited varied ecological/climate systems (biomes) including the tundra of Siberia, boreal forests, temperate deciduous forests, and temperate grassland.
The gray wolf is as interesting as a social animal as it is skilled as a predator. Wolves live in packs of seven to thirty-five, observing a hierarchy that includes parents, young and other non-breeding adults, led by the alpha male. The alpha male is usually the sole breeding male in the pack, typically pairing up with the alpha female. A male establishes its status by challenging the current alpha male in a pack, either as a lone stranger approaching an unfamiliar pack or challenging the alpha male in its own pack. The alpha male appears to dictate the pack’s activities and is even given the first chance to eat after a kill.
Wolves communicate in many ways, including posture, scent, and voice. Howling is a major component of their vocal communication, used to assemble the pack before and after a hunt, to talk to other packs, assert territorial claims or as an exclamation of pleasure. Wolves howl more frequently in the early morning and evening, particularly during breeding and pup-rearing. Howling can be heard far away. Emotion and status is usually displayed using faces and tails, while territory is marked by urine and feces.
The wolf is the largest of all wild dogs, standing at up to 30 inches (0.8m) at the shoulder, between four and five feet (1.2-1.5m) in length and weighing up to 150 pounds (68kg), although males average about 90 pounds (41kg) and females generally weigh about 80 pounds (36kg). Despite their name, gray wolves can also have white, red, or black fur.
Typically mating for life, pairs mate in winter. After a nine-week pregnancy the female gives birth to a litter of 2-14 pups in a den that the pack has dug for shelter. The pups rely on their mother’s milk in the first month but are gradually weaned and fed regurgitated meat given by the other members of the pack. Within five to seven months, the pups are capable of traveling with the pack, roaming throughout their territory, which can range over one hundred square miles (259 square kilometers).
As predators, wolves help maintain balance in the food web of their ecosystem. They are excellent hunters, capable of traveling up to 30 miles (48km) in a day to pursue prey. They typically trot at a pace of about 5 mph (8 kmph) throughout the day but they can reach speeds of up to 40 mph (64 kmph). In North America, wolves can eat a variety of animals, including field mice, although they mainly eat large ungulates, including bison, moose, deer, caribou and elk in the summer, helping to maintain sustainable prey populations. The evolutionary consequences of wolf predation can be seen today in the physical traits of prey species. The speed and alertness of the antelope and elk, respectively, and the agility of the mountain goat, are all due in part due to wolf predation. By keeping large herbivore populations under control, wolf predation allows for sustainable populations of smaller animals such as beavers and other rodents who are vital players in the ecology of their habitats.
In the early part of the 20th century, as settlers moved westward, large ungulate populations plummeted from a major increase in hunting. This drastically depleted the major source of food for the gray wolf population, which turned to cattle and sheep in order to survive. To protect livestock the campaign to eradicate the wolf population, led by ranchers and government agencies, intensified. Wolves were shot, poisoned, and hunted by dogs until only a few hundred remained in the extreme northern part of Minnesota, Canada, and Alaska. The ESA brought with it hopes for recovery of gray wolf populations. Other programs that have been initiated, including the experimental groups brought from Canada to Idaho and Yellowstone National Park in the mid 1990’s, have proven successful, and the gray wolf status has been raised from endangered to threatened in the lower 48 states. In Alaska, populations fluctuate between six and eight thousand and are not considered threatened.
Wolf management is a highly controversial topic, with conservation groups often at odds with ranchers and others who still fear for the safety of livestock and people. Many states have compensation programs for lost livestock and wolf populations are monitored to note pack interactions with human populations. Overall, it is looking hopeful for the gray wolf as it recovers from dwindling numbers and people become educated on their inherent value and vital role as predators.
U.S. Fish and Wildlife Service. Midwest Region: Gray Wolf Biologue. Updated 1/2006. www.fws.gov/midwest/wolf/
National Wildlife Federation. Wildlife: Gray Wolf. 1996-2006.
The Wild Ones Animal Index. Gray Wolf, Canis lupus. 2000.