Hunters Should Recognize Predators as Allies, not Competitors

“Predator cleansing,” a term hatched not long ago by independent wildlife researchers, doesn’t mean what it sounds like, that is, the ancient tradition of killing predators in a vain attempt to create more and better game.

Traditional predator cleansing is a fool’s errand still widely practiced by people who call themselves “hunters” and compete in predator-killing contests legal and popular in 41 states. Traditional predator cleansing is even practiced by some game and fish agencies.

I asked Dr. Rick Hopkins, who has researched cougars for 45 years, what science supports Colorado Parks and Wildlife’s claim that cougar hunting is necessary to create more mule deer. “None,” he replied. “For years game and fish agencies have made such claims, but when pushed to provide evidence, they can’t.”

My son, Dr. Scott Williams, is a deer biologist in Connecticut where wolves and cougars, the main predators of deer, have been eliminated. If traditional predator cleansing worked, his research areas would be rife with large, robust animals. Instead, they’re overrun with stunted deer that nuke wildlife habitat—including their own—and are infested with ticks that spread dangerous diseases to humans, wildlife and pets.

By limiting deer populations, predators also limit deer-tick-borne maladies such as Lyme Disease, which annually debilitates nearly a half-million Americans. If predators weren’t persecuted, they would be able to limit tick-borne diseases to a greater extent. And deer deprived of healthy predator populations serve as Covid reservoirs in which the virus mutates faster than in humans.

All threats to cervids pale in comparison with CWD. The Theodore Roosevelt Conservation Partnership, a hunter-support group, calls the disease “the biggest threat to the future of deer hunting.”

CWD was first reported in 1967 among captive mule deer in Colorado. In 1981, it spilled over to wild Colorado elk. Since then, it has spread to 35 U.S. states and five Canadian provinces along with Norway and Sweden.

“A CWD outbreak among the 60,000 to 100,000 elk in the Greater Yellowstone Basin, the largest concentration of free-ranging elk in North America, is an impending eco-disaster,” warned Dr. James Keen, wildlife veterinarian for the nonprofit Animal Wellness Action. A mule deer found dead in Yellowstone National Park in October 2023 tested positive for CWD.

The pathogen is not a virus or bacterium, but a malformed, self-replicating protein called a “prion.” It’s not alive, so humans can’t kill it by injecting animals with drugs or even by cooking infected flesh. But predators deactivate it through digestion. Deactivation is 96 to 100 percent effective, according to four peer-reviewed studies.

CWD could jump to humans. That’s why the Centers for Disease Control and Prevention warns hunters not to handle or eat infected game—in the unlikely event that they can even identify it. In 2022, two hunters who ate venison from the same CWD-ravaged deer herd died of prion disease. Given the extreme rarity of human prion infections, this seems an unlikely coincidence.

“We are quite unprepared,” said Dr. Michael Osterholm, director of the Center for Infectious Disease at the University of Minnesota. “If we saw a spillover right now, we would be in free fall. There are no contingency plans for what to do or how to follow up.”

Princeton University biologist Dr. Andrew Dobson and the late University of Calgary biologist Dr. Valerius Geist told the Denver Post in 2003 that they believe  “killing off the wolf allowed CWD to take hold in the first place.”

Keen with Animal Wellness Action notes that CWD is “killing hundreds of thousands, perhaps eventually even millions, of free-ranging deer and elk in the United States and Canada. Predator cleansing is proposed as a possible natural solution for the biological control of CWD.”

For at least a century, cougars have been essentially extirpated from the East, Southeast, Great Plains and Midwest. This may explain why CWD is now epidemic in these regions. But CWD is also epidemic where cougars persist. In some of the West, however, the disease is less prevalent where cougars are most abundant.

American-Canadian mammal biologist Dr. Paul Paquet, who has monitored CWD in wolf habitat for decades, told Mountain Journal this in 2017: “To date, and in general, CWD has not thrived where wolf populations are active.”

In Colorado, where trophy hunters annually kill about 500 cougars, CWD is epidemic and increasing. Currently, 42 of 51 deer herds and 17 of 42 elk herds are infected, according to Colorado Parks and Wildlife.

CWD is also epidemic and increasing in Wyoming, where trophy hunters annually kill about 350 cougars. In one deer herd in west-central Wyoming, 74 percent of hunter-killed male mule deer were infected with CWD, reports Daryl Lutz, a biologist with the Wyoming Game and Fish Department. “It’s the highest that’s been recorded, maybe anywhere in the world,” he said. Game and Fish reports that, statewide, 18.9 percent of all hunter-killed male mule deer in 2023 were infected with CWD, up from 17.6 percent in 2022. CWD was discovered in 30.3 percent of hunter-killed male white-tailed deer in 2023, up from 25.9 percent in 2022.

CWD was first detected in Montana in 2017. By 2024, it had spread to 17 percent of all state hunting units. “There are parts of the state where enough animals—namely white-tailed deer—have tested positive for CWD that wildlife managers are concerned about population declines like those seen in southeast Wyoming,” Montana Free Press reported in a 2021 article.

Idaho Fish and Game reports that of 442 deer it tested last year, 6.4 percent were positive for CWD.

These and similar results in other states call into question the wisdom of permissive—in some cases unrestricted—hunting and trapping of cougars, wolves, coyotes and bobcats.

At least in Colorado, hunters and other wildlife advocates can vote to help deer, elk and moose by checking “yes” on Proposition 127, a November ballot measure to protect cougars, bobcats and lynx.