Eleven Years With Wolves - What We've Learned

By Jim Lukens, Salmon Region Supervisor

Probably no other animal has generated the degree of emotions that the gray wolf has. This may be in part because of folklore and human nature.

Literature, song and history are filled with references to the wolf as a vicious or demonic creature. Native cultures in North America and elsewhere credit the wolf with almost mythical power. Neither is true. Wolves are predators.

Since 1995 when they were reintroduced in Idaho, Idaho Fish and Game biologists have been observing wolves in their natural state. Below is a summary of some of what they have learned.

Distribution, Number and Ancestry
By the end of 2008, biologists documented 88 resident wolf packs in Idaho, observed a minimum of 846 wolves. The Salmon Region was occupied by 13 documented resident packs, and by three documented and one suspected border packs during 2005.

The U.S. Fish and Wildlife Service recognizes only the gray wolf, Canis lupus for recovery purposes. Wolves from Canada moved to northwest Montana and northern Idaho on their own before reintroductions and since.

There is little evidence to support the claim that wolves used to be smaller than the reintroduced ones. All animals tend to be larger the farther north they are in their species range, and the less animals have to eat, the smaller their body size tends to be. When wolves were eliminated in Idaho at the beginning of the twentieth century, homesteaders, miners, American Indians, and others had depleted wolves' natural prey. Prey is more abundant now then when wolves were eliminated, thus, they may weigh more.

They are not a different species.

When considering trapping locations for the wolves to be released into Idaho, biologists selected populations already preying on elk. This increased the suitability of these wolves for life in Idaho.

Wolf Predation
Wolf predation data from one area does not necessarily represent predation characteristics from other wolf-prey systems. But the tendency for wolves to select prey that are disadvantaged in some way, such as the young, the old, and the sick, injured or weak individuals. Because of their pursuit-style of hunting, wolves tend to encounter prey that are slower or weaker in some way, thus vulnerable to being singled out by wolves.

Jason Husseman, the Salmon Region wolf biologist, examined 120 wolf kills as part of a winter wolf and mountain lion predation study in Unit 28 as part of his Master's degree from 1999 - 2001. The wolf kills comprised 77 percent elk and 23 percent deer.

Of the elk kills 60 percent were calves; 32 percent were cow elk; and 8 percent were bulls. The average age of adult elk killed by wolves was 12.6 years; the average age of a sample of 31 cow elk killed by hunters was 7.3 years. And 65 percent of deer taken by wolves were fawns.

Each wolf pack in the study area made a kill every two to three days. Once prey adapted to wolves, however, predation rates by wolves declined. Prey animals are more difficult to kill on dry ground when they are in good condition than in winter when prey condition is poorer and snow makes it tougher to escape.

Husseman found that 80 percent of kills were more than three-quarters eaten, and all kills were at least partially eaten. While "surplus killing," -killing in excess of what could be consumed in the immediate future-has been documented, such incidents usually occur under atypical conditions, such as unusually deep snow. And wolves often return to eat the "leftovers."

Husseman classified the health of each prey animal killed by wolves or lions by measuring bone marrow fat content. Bone marrow fat is the last fat reserve used by deer and elk during winter. Once bone marrow fat falls below a certain level, the animal will not survive.

He found that 25 percent of the animals killed by wolves would have died of malnutrition. He also found the condition of elk killed by wolves was consistently poorer than that of elk taken by mountain lions, and elk condition worsened through the winter.

Status of Big Game Herds
Obviously wolves prey on deer and elk along with lions, black bears and several other predators. To determine the effect on game herds, biologists monitor the status of game herds with aerial surveys and hunter harvest information.

At the time wolves were released into Idaho, the elk herd in Salmon Region numbered about 28,000 animals. The latest estimate is about 21,300 animals.

Since wolves were reintroduced, deer herds have remained near objectives. The most likely limiting factors for mule deer in the Salmon Region are habitat conditions and weather.

Threat to Humans
All wild animals can be hazardous to humans with outcomes ranging from discomfort to death. Two behavioral changes can increase animals' likelihood of injuring humans: when an animal becomes habituated to humans by repeated contacts without injury, and when an animal becomes food-conditioned by a reward of food for a given behavior.

The first probable human fatality in North America since 1900 attributed to wolves occurred in November 2005, in northern Saskatchewan. Wolves in the area had been attracted to a garbage dump, may have been fed at a nearby mining camp and been food-conditioned, and regularly photographed by humans thereby becoming habituated.

In A Case History of Wolf-Human Encounters in Alaska and Canada, Mark McNay documents 80 cases of wolf-human interactions (aggressive and nonagressive) that have occurred in the past 60 years: 36 in Alaska, 41 in Canada and three in Minnesota. None was fatal, and 25 involved unprovoked aggression by healthy wolves, but only 13 of those involved injury to humans.

In the other 55 cases, 14 wolves acted in self-defense; 12 were known or suspected to have rabies; and 29 showed interest but no aggression.

Most of the unprovoked attacks by healthy wild wolves were by wolves that become habituated to humans or food-conditioned and aggressive.

Some cases of aggression in the report and in Idaho were related to the presence of a dog with the person. Wolves don't usually like other canids in their territory.