Livestock Depredation by Wolves

            My previous post reviewed the issue of wolf reintroduction from a conservationist stand-point. A conversation with my advisor at Iowa State University the other day made me look at it from the alternate perspective of livestock owners in areas where wolves have been reintroduced. My advisor is Dr. Stephanie Hansen, a beef nutritionist; when I mentioned my blog, she told me about her experiences with this issue. Each year, Dr. Hansen takes a group of students to Yellowstone. As part of this trip, they visit with both park rangers and ranchers. Understandably these two groups have very different views of wolf conservation. Dr. Hansen mentioned that wolf predation upon livestock is a huge problem for ranchers in that area and that she has heard several stories from ranchers who have found calves or sheep killed by wolves but not eaten. Hearing these stories made me want to explore the issue of wolf-livestock interactions and I found an article which deals with various facets of that relationship.

            The article is a report on a study done on the effects of livestock depredation by wolves on the livestock industry in Idaho, Montana, and Wyoming¹. The study area contains both natural prey species for wolves as well as domestic livestock, and agricultural lands and towns as well as public reserves. Livestock depredation is primarily an issue due to the overlap between wolf range and private and public range lands used for livestock grazing.

An important issue addressed by this study is the belief that wolves kill livestock in excess of their food needs, also known as surplus killing. The authors suggest that surplus killing by wolves may occur at a higher rate for domestic animals than for the wolves’ wild prey due to the fact that artificial selection for desirable production traits has reduced the animals’ tendencies for certain anti-predator behaviors.

            This study documented attacks of wolf on sheep and cows in the three states mentioned above from 1987-2003 and analyzed the number killed per attack and the biomass consumed of each carcass. Over the entire study, 219 cows were killed by wolves in 158 attacks and 602 sheep were killed in 68 attacks. The data on biomass consumed indicate that the majority of these attacks were motivated by a need for food. However, wolves utilized a greater percentage of the carcass in attacks on cattle and killed more than they needed more often when attacking sheep than when attacking cattle. The data indicate that wolves do exhibit surplus killing on sheep but not on cattle. The authors admit that this data may be biased due to the inability to know how many wolves were involved in each individual attack.

             In addition to surplus killing, Muhly and Musiani examined the efficacy of livestock compensation programs. These programs have been utilized for more than 20 years in this area in an attempt to reduce the animosity of livestock producers toward wolves. The importance of prompt payment of compensation is highlighted, as producers need to quickly replace an animal in order to avoid further loss of profit, which is gained from growth and reproduction. Even if payment is immediate, however, these programs are further limited because they are unable to compensate for loss of important breeding animals or emotional investment.

Another element to take into account when considering the costs of wolf conservation to livestock producers is the benefit which private rangelands pose to wolves. For wolves and their prey species, these rangelands provide invaluable habitat. Current trends in livestock and land value make selling these rangelands financially attractive to many livestock producers. Due to increasing demand for natural amenities, many rangelands are being converted to rural-residential developments. The authors suggest that public funds allotted for wolf conservation may be well-put towards supporting the livestock production industry in these areas, with the goal of conserving rangelands.

This article seems to be written from a perspective which sides with wolf conservation, but is open to understanding and meeting the needs of livestock producers. I believe that if this type of attitude were more prevalent among both conservationists and livestock producers, much of the controversy and animosity surrounding wolf reintroduction could be resolved. It is clear to me that there is no answer that can satisfy everyone. Wolves pose a threat to the livelihood of livestock producers, but they also pose many benefits to the ecosystem in this area. Given that, I believe that people on both sides of this issue need to be open-minded and seek to fully understand the opposing perspective. If this can be achieved, a compromise could be reached.

When reading the results section of this article, I thought back to what Dr. Hansen had told me of her interactions with livestock producers who deal with wolf predation. It seems to me that several of them would have reason to disagree with the authors’ conclusion that surplus killing of cattle by wolves is not common. I think part of the compromise that needs to occur is for scientific-minded conservationists to understand that livestock producers who lose cattle to wolves will not necessarily allow their opinion of wolves to be swayed by purely scientific conclusions such as those presented in this article.

Compensation programs, as described in this article, seem to be a good start toward finding a compromise between livestock owners and wolf conservationists. However, I agree with the authors’ recommendation that compensation payments must be as prompt as possible in order to be meaningful within the economic context of the livestock industry. Another part of the necessary compromise is that compensation agencies should strive to understand the livestock industry in order to be on the same page as their payees. Also, the livestock producers should accept that compensation is not a perfect answer and it is unrealistic to expect compensation to cover every aspect of the lost animal, such as emotional investment.

Livestock-wolf interactions are a huge part of the controversy surrounding wolf reintroduction. This article is a solid foundation for understanding those interactions and what steps need to be taken to resolve animosity between conservationists and livestock producers.

1.Muhly, T.B., & Musiani, M. (2009). Livestock depredation by wolves and the ranching economy in the Northwestern   U.S. Ecological Economics, 68(8), 2439-2450.