Compiling data from all complaints of wolf interactions with dogs within Minnesota's wolf range between 1979 and 1987, the authors conclude that interspecific aggression alone may not explain wolf attacks on dogs, and that in some cases wolves view dogs as prey. This study is deemed important as wolf depredation on pets can cause anti-wolf feeling in recovery areas.
Wolves (Canis lupus) are the progenitors of dogs (C. familiaris), and the 2 species interbreed. They also fight with one another, and wolves are known to eat dogs, but such interactions are mentioned only briefly in scientific literature. In the United States out of Alaska, the wolf exists only in Minnesota...and in parts of northern Wisconsin, Michigan, northwestern Montana, and possibly Idaho....Recovery plans for the eastern timber wolf, Northern Rocky Mountain wolf, and Mexican wolf identify other areas of the United States for potential reintroduction....
....A major issue in public acceptance of wolves is the potential for depredation on domestic animals. Current information on wolf interactions with domestic animals in North America is scarce, and information on the specific problem of depredations on dogs is especially rare. We report on the nature and extent of wolf-dog interactions in Minnesota, based on investigations of complaints received by personnel of the federal government dealing with wolf-depredation control. Our findings may indicate the wolf-dog interactions that can be expected in other recovery areas.
STUDY AREA AND METHODS
A general description of the 59,000-square km. wolf range in Minnesota is provided in Bailey (1978). With larger towns excluded, the area includes about 68,000 households whose dogs migh be exposed to wolves. Most of the wolf range is rural, including many small communities and single residences.
Complaints of wolf interactions with domestic animals were received by our office from the public during 1979-1987. We field checked all complaints as soon as possible, normally within 24-48 hours, and verified whether wolves had killed or wounded [one or more] dogs. Identification of wolf-inflicted damage was based on (1) size and location of bite marks on dogs; (2) identification of wolf tracks, droppings, or other wolf sign in the immediate vicinity of attacks; and (3) observations related by dog owners.
RESULTS AND DISCUSSION
From 1979 through 1987 we received 47 complaints of wolf-dog interactions (8% of all wolf-domestic animal complaints received). In 19 (40%) of the events, the owner had merely expressed concern about the safety of dogs, an encounter had occurred without damage, or damage had occurred, but we determined that wolves were not responsible. In 28 (60%) instances, we verified that wolves had wounded or killed dogs. In total, owners claimed that 54 dogs were wounded, killed, or missing. Our investigations confirmed that wolves had killed at least 24 dogs and wounded another 10. These figures indicate the minimal extent of wolf-dog conflicts, because it is not likely that all attacks on dogs were reported.
Wolves killed dogs during every year of our study, with 1-8 complaints received annually, and 1-6 verified reports. The year of highest depredations was 1984 when 20 dogs were reported killed, wounded, or missing, and 9 were confirmed killed or wounded....
....Only 4 of 47 complaints of wolf-dog interactions in Minnesota were associated with concurrent complaints of depredations on livestock. Tompa (1983) reported comparable figures from Alberta. Therefore, wolves showed no strong inclination to attack dogs at residences near where they were already preying on livestock. Dogs were the only domestic animals available at many depredation sites. Generally, rural residences and those at the edge of small communities in areas of high wolf populations seemed most likely to experience problems.
Although depredation on livestock has a predictable seasonal pattern, occurring primarily between May and October, no seasonal pattern was evident for depredations on dogs....Tompa (1983) reported that all 13 attacks on 29 dogs in a 3-year period in Alberta occurred between October and March; wolves were closer to human settlements during that period of the year because of shifts in distribution of wild prey.
Several breeds of dogs were killed, ranging in size from a miniature poodle to a Norwegian elkhound. Based on our investigations and interviews with dog owners, we believe that small- to medium-size dogs, which may be particularly excitable and vocal, are more likely to provoke attack by wolves. No selection for sex was apparent.
Of 19 dog carcasses we examined, 14 were partially or fully eaten....
While preying on dogs, wolves displayed a lack of fear of humans and buildings that is otherwise unknown except when they are diseased, disabled, or preying on deer. In several incidents investigated, wolves evidently focused their attention on dogs so intently that they were almost oblivious to buildings and humans. Most wolf attacks on dogs, including the fatal ones, occurred in the property owner's yard and, with only 2 exceptions, within 100 m. of the owner's house. In 1 case, a wolf attacked a dog near the doorstep and would not retreat until beaten with a shovel. This incident occurred after the owner had recently lost another dog, and neighbors had allegedly lost 2 dogs. Four fatal interactions involved dogs chained to a residence or a doghouse. In those instances, the dog's collar was broken and the dog was carried away. In 1 case the doghouse was dragged into the adjacent woods with the dog carcass.
Several complaints were clustered in time and space. This finding suggests that individual wolves or packs were seeking dogs rather than encountering them at random. The most extreme example was the prolonged episode at Isabella where we received reports that dogs were killed or wounded from June through September 1984. In that instance, the problem seemed to have been caused by a single wolf pack with a rendezvous site 6.5 km from town. In at least 2 other cases, a wolf or wolves attacked several dogs in the same community within a period of a few days.
Wolf depredation on dogs was not a common problem; only a small fraction of the 68,000 potential households that may have possessed dogs were affected. Nonetheless, the problem of wolves attacking dogs can be substantial locally and can produce anti-wolf reaction that could hamper recovery of wolf populations....Some attacks on Minnesota dogs were covered by the news media, which amplified public reaction.
The persistence of some wolves in seeking dogs, prolonged attacks locally, and the fact that 75% of the carcasses found were fed upon suggested that interspecific aggression alone may not explain why wolves kill dogs. Conceivably, dogs may be perceived as prey and deliberately hunted in some instances....