BioEd Online

A new map may help predict where wild wolves are most likely to attack domestic animals. The colour-coded chart could be used to identify future trouble spots, and aid wildlife-friendly efforts to reduce further run-ins.

Wild wolves are increasing in number in the US with around 4,000 now living in Wisconsin, Minnesota and Michigan. But as the population increases, so too does the frequency of attacks on domesticated animals, such as cattle, dogs and deer.

Over the last 25 years, around 1,000 attacks were reported in Minnesota and Wisconsin. Adrian Treves from the Wildlife Conservation Society in New York and colleagues studied their locations and used them to map out where in the two states future attacks are likely to occur. Their vibrant chart is published in Conservation Biology¹; high-risk spots are shaded red, lower-risk areas are coloured blue.

The map suggests that big farms are more vulnerable than small ones. This may be because large livestock herds wander away from farmsteads and human habitation, making them more vulnerable to attack, says Treves.

Pasturelands edged with forest are another attack hotspot. Wolves visit the pastures because they often contain white-tailed deer, a natural source of prey. If there are farmsteads nearby, wolves may attack penned-in livestock, says Treves. Forests offer cover and an easy escape route.

Wolves are also more likely to attack when they are at the edge of their territorial range. This could be because they are less familiar with landscape, and do not know where the best sources of wild prey are.

Keeping the wolf from the door

The map gives policy-makers the chance to take preventative measures, says Treves. Farmers who are at risk could buy guard dogs or put up better fencing, he says.

Wherever humans and wolves share the land, there will be conflict, says Rolf Peterson, a wildlife biologist at Michigan Technological University. Farm animals cannot escape, making them easy targets for wolf attacks.

Predictions can also help policy-makers allocate resources, which are scarce, to areas with the highest risk. "They need to see a map," says Peterson, although he believes that having people on the ground that know the landscape and wolves is the best way to control conflicts.

The map could also show people that the risk of a wolf attack is lower than they may think. In Wisconsin, now home to around 350 wolves, only 0.3% of land falls into the highest risk category. "Information is empowering," says Treves, it makes people less likely to panic or despair.

Attacks not only increase anti-wolf feeling and fear, they are also costly. Government authorities compensate owners when their animals are killed. One payment, for several trophy stags killed by wolves, was US$48,000.