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The Cost of the Wild


Pat Shipman








“No, look,” I said. They looked.











Casting a Wider View

I still replay these events in my head, unable to believe I was so lucky as to witness this drama and see so many wolves.

Wolves in Yellowstone generate controversy. Although wolves were in Yellowstone when it was first discovered, they were hunted into local extinction by European settlers. The last wolf was deliberately killed in Yellowstone in 1926. From then until 1995 there were no wolf packs in Yellowstone.

In 1995 and 1996, a total of 31 wolves from two areas in Canada were reintroduced into Yellowstone in the Lamar Valley. The idea was to rebalance the ecosystem to a 19th-century state and put more wolves into a protected area. There are now 10 packs and approximately 100 wolves in Yellowstone. The effects of reintroduction are ongoing.

2012-11MargShipmanFB.jpgClick to Enlarge ImageOne of the more obvious changes is a decline in the elk population. The herd also tends to stay in smaller groups than previously. Fewer elk overall means that the cottonwoods, willows and aspens along the rivers now form denser, healthier stands because their shoots are not eaten to the ground by over-abundant elk.

Beaver are increasing, damming up rivers, creating new meadows and providing new habitats for songbirds and fish. Coyotes are hard-hit by the wolves, which kill them as competitors. The coyote population has dropped precipitously, since those that are not killed tend to avoid areas with wolves. Because coyotes used to suppress fox populations, foxes are expected to be more common. All kinds of scavengers, from ravens to bears, have more carcasses to eat. Finally bison—which only a few wolf packs have learned to kill—are still growing in number but now wander outside of the park in larger numbers. Perhaps they are avoiding wolves too.

Where’s the controversy? Ask the ranchers in Paradise Valley, just outside the park, what they think of the reintroduction. “How would you feel if somebody plonked down a pack of wolves in your backyard?” they say, with good reason. Some have been on the land since the 1800s and never had a “wolf problem” before reintroduction. They fear for their children, grandchildren, pets and livestock.

These ranchers make their living by raising cattle or sheep. It is hard work but involves an independent lifestyle they love. Unfortunately, wolves do not distinguish between domestic livestock and wild ungulates, except that they may have figured out that domestic livestock are conveniently fenced in and cannot run as far. Compensation is available for ranchers who lose animals but is difficult to qualify for. You have to find the kills right away, and there has to be enough of each animal left to show the pattern of consumption typical of wolves, not some other predator.

I was told a story—possibly exaggerated—of a woman who raises sheep. One night wolves got into her pasture and killed 35 animals. Most were so thoroughly consumed she could not get compensation. Sadly, within a few days, every living ewe in that rancher’s herd aborted because of stress. She lost an entire year’s production and income.

Wolves are also linked to bison. The Yellowstone bison herd had shrunk to a mere 25 individuals before the area was declared a park and protected. In the 19th and early 20th centuries, bison were aggressively hunted in the west, partly for food and partly as a strategy to deprive the Plains Indians—considered enemies of European settlers—of the animals that provided much of their food. Bison still have great symbolic power for the tribes.

2012-11MargShipmanFC.jpgClick to Enlarge ImageToday, the bison herd is 3,500–4,000 individuals. The reintroduction of wolves has checked their numbers somewhat, but once a bison is full-grown it is too large for wolves or grizzlies to take. Bison leave the park in search of grazing, especially in bad winters. Paradise Valley—the same area the wolves go to—is at a lower elevation than the park and gets less snow. It is an ideal winter range for bison and for cattle.

More than Predation

Competition for grass and forage is not the heart of the problem; brucellosis is. Brucellosis is a bacterial disease originally found in cattle that spread long ago to the bison. The disease causes pregnant females to abort their fetuses, expelling fluids and tissues that then infect other animals in the same area. Brucellosis has been eliminated from the domestic cattle population through mandatory annual vaccinations and aggressive slaughter of all animals in an infected herd. About 45 percent of the Yellowstone bison and 5–10 percent of the elk still carry brucellosis. Vaccinating bison only at boundary facilities will probably not reduce the rate of brucellosis infection in the herd long term, but a consistent, park-wide effort would be “controversial, logistically challenging, expensive, and intrusive, with no guarantee of successfully reducing brucellosis prevalence to near zero” according to a 2011 article written by a group of Yellowstone Park rangers in Biological Conservation.

Though all female cattle are vaccinated, the vaccine is not 100 percent effective. If brucellosis is transmitted to their livestock by wildlife, ranchers face the devastating destruction of their entire herd. Further, if only two cases of brucellosis-infected cattle are discovered, the entire state loses its “brucellosis-free” status. Cattle from a state that is not brucellosis-free bring less money, and their transport across state lines is difficult and tightly regulated. The stakes are very high.

Bison straying outside the park are hazed by helicopter and by individuals on horseback or on all-terrain vehicles in an attempt to drive them back into the park. When the grazing is exhausted in the park, some bison refuse to return and face starvation. Those that remain outside the park are rounded up, penned and tested for brucellosis—very stressful events. Animals that test positive are killed. The article by the Yellowstone Park rangers attests: “About 3,100 bison were culled from the [Yellowstone] population during 1985–2000 for attempting to migrate outside the park.”

Culling a once-endangered species that is a vital component of the Yellowstone ecosystem seems wrong. It offends every conservationist’s deepest beliefs. These animals are only reoccupying their former range as circumstances demand (see map). Unfortunately, their presence in cattle-ranching areas and their infection with brucellosis pose a serious economic threat to ranchers.

Some regard the presence of bison as inevitable: “If you don’t want bison on your land, move to Ohio,” one rancher said. Others stress the inherent unfairness of endangering their carefully built herds and lifestyle with a wild animal that is supposed to be kept inside the park. They demand that a management plan be devised for the bison that will protect their herds from the risk of infection.

Bison advocates like the Buffalo Field Campaign demand that the animals be left to roam free and experience the consequences of natural selection. They emphasize that only the Yellowstone herds and those in Wind Cave National Park are free from genes resulting from crossbreeding with cattle—a strategy used by ranchers to make bison more docile.

The Yellowstone Park herds are genetically uncontaminated and have occupied their range since prehistoric times. Whatever knowledge, instincts or abilities have evolved in wild bison to help them survive in a rugged landscape with harsh winters, the Yellowstone herd has them.

Like wolves, bison also pose a danger to humans. Humans can become infected with the brucellosis bacterium, which gives them undulant fever, a very nasty, often incurable, recurrent disease. It is worth stressing that bison are not cute Disney animals; they are 2,000 pounds worth of strength, ferocity and unpredictability. While I was in Yellowstone, a tourist, who foolishly approached a bull bison much closer than park regulations allow, was gored and sent to the hospital. Bison injure more visitors to Yellowstone than bears do.

Wolves and bison are only two of the controversial issues in Yellowstone, our first and perhaps greatest national park. How can we balance the rights of the individual with those of the majority? There is a real price to pay for preserving our wild heritage. We must listen to the opinions of all the stakeholders to negotiate a just and equable solution to these complex problems.


  • Hedrick, P. W. 2009. Conservation genetics and North American Bison (Bison bison). Journal of Heredity 2009:100(4):411–420. doi:10.1093/jhered/esp024
  • White, P. J., Rick L. Wallen, Chris Geremia, John J. Treanor and Douglas W. Blanton. 2011. Management of Yellowstone bison and brucellosis transmission risk: Implications for conservation and restoration. Biological Conservation 144:1322–1334. doi:10.1016/j.biocon.2011.01.003

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