Colorado finally got its wolves back. Why are so many dying?

This story was originally published by Vox and is reproduced here as part of the Climate Desk collaboration.

On a sunny morning two years ago, a group of state officials stood in the mountains of northwestern Colorado in front of a handful of large metal crates. With a small crowd watching them, the officials began to unlatch the crate doors one by one. Out of each came a gray wolf—arguably the nation’s most controversial endangered species.

This was a massive moment for conservation.

While gray wolves once ranged throughout much of the Lower 48, a government-backed extermination campaign wiped most of them out in the 19th and 20th centuries. By the 1940s, Colorado had lost all of its resident wolves.

But, in the fall of 2020, Colorado voters did something unprecedented: They passed a ballot measure to reintroduce gray wolves to the state. This wasn’t just about having wolves on the landscape to admire, but about restoring the ecosystems that we’ve broken and the biodiversity we’ve lost. As apex predators, wolves help keep an entire ecosystem in balance, in part by limiting populations of deer and elk that can damage vegetation, spread disease, and cause car accidents.

In the winter of 2023, state officials released 10 gray wolves flown in from Oregon onto public land in northwestern Colorado. And in January of this year, they introduced another 15 that were brought in from Canada. Colorado Parks and Wildlife (CPW)—the state wildlife agency leading the reintroduction program—plans to release 30 to 50 wolves over three to five years to establish a permanent breeding population that can eventually survive without intervention.

“Today, history was made in Colorado,” Colorado Gov. Jared Polis said following the release. “For the first time since the 1940s, the howl of wolves will officially return to western Colorado.”

Fast forward to today, and that program seems, at least on the surface, like a mess.

Ten of the transplanted wolves are already dead, as is one of their offspring. And now, the state is struggling to find new wolves to ship to Colorado for the next phase of reintroduction. Meanwhile, the program has cost millions of dollars more than expected.

The takeaway is not that releasing wolves in Colorado was, or is now, a bad idea. Rather, the challenges facing this first-of-its-kind reintroduction just show how extraordinarily difficult it is to restore top predators to a landscape dominated by humans. That’s true in the Western US and everywhere—especially when the animal in question has been vilified for generations.

One harsh reality is that a lot of wolves die naturally, such as from disease, killing each other over territory, and other predators, said Joanna Lambert, a wildlife ecologist at the University of Colorado Boulder. Of Colorado’s new population, one of the released wolves was killed by another wolf, whereas two were likely killed by mountain lions, according to Colorado Parks and Wildlife.

The changes that humans have made to the landscape only make it harder for these animals to survive. One of the animals, a male found dead in May, was likely killed by a car, state officials said. Another died after stepping into a coyote foothold trap. Two other wolves, meanwhile, were killed, ironically, by officials. Officials from CPW shot and killed one wolf—the offspring of a released individual—in Colorado, and the US Department of Agriculture killed another that traveled into Wyoming, after linking the wolves to livestock attacks. (An obscure USDA division called Wildlife Services kills hundreds of thousands, and sometimes millions, of wild animals a year that it deems dangerous to humans or industry, as my colleague Kenny Torella has reported.)

Yet, another wolf was killed after trekking into Wyoming, a state where it’s largely legal to kill them. Colorado Parks and Wildlife has, to its credit, tried hard to stop wolves from harming farm animals. The agency has hired livestock patrols called “range riders,” for example, to protect herds. But these solutions are imperfect, especially when the landscape is blanketed in ranchland. Wolves still kill sheep and cattle.

This same conflict—or the perception of it—is what has complicated other attempts to bring back predators, such as jaguars in Arizona and grizzly bears in Washington. And wolves are arguably even more contentious. “This was not ever going to be easy,” Lambert, who’s also the science adviser to the Rocky Mountain Wolf Project, an advocacy organization focused on returning wolves to Colorado, said of the reintroduction program.

There’s another problem: Colorado doesn’t have access to more wolves.

The state is planning to release another 10 to 15 animals early next year. And initially, those wolves were going to come from Canada. But in October, the Trump administration told CPW that it can only import wolves from certain regions of the United States. Brian Nesvik, director of the US Fish and Wildlife Service, a federal agency that oversees endangered species, said that a federal regulation governing Colorado’s gray wolf population doesn’t explicitly allow CPW to source wolves from Canada. (Environmental legal groups disagree with his claim).

So Colorado turned to Washington state for wolves instead.