Return of the Wolf

AH-WOOO! Hundreds of years ago, the howls of gray wolves rang out across much of the western and northern United States. The animals were one of North America’s top predators. Then, in the 19th century, large numbers of people began settling in the wolves’ territory. That didn’t bode well for the wolves. They sometimes killed cows, sheep, and other livestock on ranches and farms, as well as deer and elk that people hunted. “People perceived wolves as a threat,” says Mark Ditmer, an ecologist with the U.S. Forest Service’s Rocky Mountain Research Station in Fort Collins, Colorado.

As the human population continued to grow, so did people’s conflicts with wolves. In the early 1900s, federal and state governments introduced a policy to eradicate, or kill off, gray wolves throughout most of the country. By the 1950s, only small populations of wolves remained in Minnesota and Michigan, along with a larger one in Alaska.

In the 1960s, scientists realized that “large predators like wolves are really important for proper functioning of an ecosystem,” says Ditmer. An ecosystem is a community of living things interacting with their physical environment. But by that time, gray wolves were on the verge of extinction, or dying out. That’s why in the 1970s, the species was granted protection under the federal Endangered Species Act (see 50 Years of Saving Species). The act made it illegal to harm or hunt wolves and directed federal agencies to protect them.

AH-WOOO! Hundreds of years ago, that call sounded across much of the western and northern United States. It was the howl of gray wolves. These animals were one of North America’s top predators. But in the 19th century, many people began to settle in the wolves’ territory. That meant trouble for the wolves. Wolves sometimes killed cows, sheep, and other livestock on ranches and farms. They also ate deer and elk that people hunted. “People perceived wolves as a threat,” says Mark Ditmer. He’s an ecologist with the U.S. Forest Service’s Rocky Mountain Research Station in Fort Collins, Colorado.

The human population continued to grow. And so did people’s conflicts with wolves. In the early 1900s, federal and state governments decided to eradicate gray wolves. They killed off these animals in most of the country. By the 1950s, only small populations of wolves were left in Minnesota and Michigan. A larger group remained in Alaska.

In the 1960s, scientists realized that “large predators like wolves are really important for proper functioning of an ecosystem,” says Ditmer. An ecosystem is a community of living things along with their physical environment. By then, gray wolves were close to extinction, or dying out. So in the 1970s, they were given protection under the federal Endangered Species Act (see 50 Years of Saving Species). That made it illegal to harm or hunt wolves. It also directed federal agencies to protect them.

Wildlife agencies also reintroduced small numbers of gray wolves into protected areas. In 1995, government officials from the U.S. and Canada released wolves into Yellowstone National Park, which encompasses parts of Wyoming, Montana, and Idaho. The animals have since expanded into Oregon, Washington, and California (see Wolf Territory, below). In December 2023, if all goes according to plan, gray wolves will be released into Colorado—but not because of a decision by government officials. In a historic first, the people of Colorado voted for their state to reintroduce the endangered species.

Wildlife agencies also wanted to return small numbers of gray wolves to protected areas. In 1995, government officials from the U.S. and Canada worked together on this. They released wolves into Yellowstone National Park. The park covers parts of Wyoming, Montana, and Idaho. Since then, the animals have spread into Oregon, Washington, and California (see Wolf Territory). In December 2023, the plan is to release a new group of gray wolves into Colorado. But it’s not because of a decision by government officials. For the first time, people voted for their state to reintroduce the endangered species.

Colorado Parks & Wildlife (CPW) is overseeing the state’s gray wolf reintroduction. The agency wants to make sure the program is a success for both wolves and the people they’ll be living alongside. CPW realizes it will have to manage the program “with an understanding that wolves will have both positive and negative impacts,” says spokesperson Travis Duncan.

The biggest positive will be restoring wolves to their role at the top of the food web—the interconnected system in which organisms eat other organisms to obtain energy. Wolves are top predators that help keep populations of their prey, such as deer and elk, in check. Controlling deer and elk numbers can prevent overgrazing of plants that these animals eat.

Colorado Parks & Wildlife (CPW) is managing the state’s gray wolf reintroduction. Wolves and people will be living next to one another. The agency wants the program to be a success for both. CPW will have to manage the program “with an understanding that wolves will have both positive and negative impacts,” says spokesperson Travis Duncan.

The biggest positive is that wolves will return to their important role. They’re at the top of the food web—the interconnected system of organisms eating other organisms to get energy. Wolves are top predators. They help keep populations of their prey in check. That includes deer and elk, which eat plants. Controlling deer and elk numbers can prevent overgrazing.

But to see such ecosystem benefits, Colorado will need a wolf population that’s viable—or able to reproduce and sustain itself over time and support multiple packs. Over the past several years, a handful of wolves have made their way into Colorado from nearby states. In most cases, these scattered individuals didn’t survive or eventually migrated elsewhere. CPW hopes to release 30 to 50 wolves from other Western states into Colorado over the next three to five years. Previous reintroductions in the U.S. have shown that wolves can travel long distances from the spot where they’re released. To increase the odds of the animals remaining in Colorado, officials will set wolves free within the state, at least 97 kilometers (60 miles) from its borders.

No matter where the wolves are released, experts expect that they could spread widely in Colorado. “As long as prey is available, wolves can live in a variety of areas,” says Duncan. That means wolves are likely to end up in places where they’ll be welcomed by their human neighbors—as well as in places where people would rather not have them around.

To get these ecosystem benefits, Colorado will need a viable wolf population. It must reproduce, continue over time, and support multiple packs. Over the past several years, a few wolves have moved into Colorado from nearby states. Most of these wolves either didn’t survive or moved somewhere else. CPW hopes to release 30 to 50 wolves from other Western states into Colorado. This will happen over the next three to five years. Wolves can travel long distances from their spot of release. Officials have learned this from earlier reintroductions in the U.S. They want the animals to stay in Colorado. So they’ll set wolves free within the state, at least 97 kilometers (60 miles) from its borders.

Experts expect that wolves could spread widely in Colorado. That’s true no matter where they’re released. “As long as prey is available, wolves can live in a variety of areas,” says Duncan. So wolves will probably end up in places where their human neighbors welcome them. But they’ll also likely go where people don’t want them around.

Many of the same conflicts that emerged between wolves and people nearly a century ago are still relevant today—a reality reflected in the results of the state election. “Reintroducing wolves was the will of the people,” says Ditmer, “but it passed very narrowly.” The final tally showed 51 percent of voters in favor of bringing back wolves and 49 percent against.

Threats to livestock remain a big concern among Colorado ranchers and farmers. So CPW is working with these groups to help reduce the risks of wolves attacking livestock. The agency is lending out strands of electrified wiring to help keep wolves out of livestock areas, along with loud noisemaking devices and bright flashing lights to scare the predators away.

Nearly a century ago, conflicts arose between wolves and people. Many of those same conflicts cause concern today. The results of the state election reflect this. “Reintroducing wolves was the will of the people,” says Ditmer, “but it passed very narrowly.” The results showed 51 percent of voters in favor of bringing back wolves. But 49 percent voted against it.

Colorado ranchers and farmers are concerned about threats to livestock. So CPW is trying to reduce the risk of wolf attacks on these animals. The agency is lending out equipment to ranchers and farmers. Strands of electrified wiring will help keep wolves out of livestock areas. Loud noisemaking devices and bright flashing lights will help scare the predators away.

If wolves kill livestock, CPW will pay the ranchers or farmers for the animals. That will make up for their financial losses. With this system, conservationists hope that people won’t view wolves as a threat to their livelihoods. Then they may feel more comfortable about having wolves in the state.

CPW will also provide financial compensation to ranchers or farmers whose animals are killed by wolves to make up for their losses. Conservationists hope that with this system in place, people won’t view wolves as a threat to their livelihoods and will be more tolerant of their presence in the state.

Ditmer and colleagues at the U.S. Forest Service have analyzed the distribution of wolf prey along with factors including how different counties voted on reintroduction. Using this data, they created maps of where the predators are most likely to thrive—and where they might run into trouble with people. Identifying areas with a combination of prey that will attract wolves and residents who are wary of wolves’ return could help CPW identify where to focus their efforts at preventing conflict.

“Growing up, seeing the efforts to reintroduce wolves to Yellowstone was one of the things that inspired me to work in wildlife ecology,” says Ditmer. Bringing wolves back to Colorado, he says, “is a complex undertaking with a lot of work ahead. It may not always be smooth or easy, but it’s important and really exciting.”

Ditmer and his co-workers at the U.S. Forest Service examined different factors. They studied the locations of wolf prey, along with how different counties voted on reintroduction. Then they used this data to create maps. The maps show where wolves are most likely to thrive. They also show where the predators might run into trouble with people. Some areas have both prey that will attract wolves and people who worry about the wolves’ return. So the CPW can focus on these areas to try to prevent conflict.

“Growing up, seeing the efforts to reintroduce wolves to Yellowstone was one of the things that inspired me to work in wildlife ecology,” says Ditmer. He says that returning them to Colorado “is a complex undertaking with a lot of work ahead. It may not always be smooth or easy, but it’s important and really exciting.”