In 1939, Adolph Murie began following wolves across Denali; his landmark study challenged the belief that predators should be eliminated

In April 1939, biologist Adolph Murie arrived in Mount McKinley National Park with a notebook and a hard question to answer: why were there fewer Dall sheep than before, and what role did wolves play in that decline? Many people at the time were certain they knew the answer: wolves were killing off the sheep. Murie's job was to find out whether that was actually true.

According to the National Park Service's biography of Murie, the two years of fieldwork that followed gave park managers the evidence they needed to eventually eliminate predator control in Mount McKinley National Park. Murie's task was clear: find out why the park had fewer Dall sheep than it once did, and determine what role, if any, wolves played in that decline, the same question many at the time believed they'd already answered.

Records show he went to Mount McKinley National Park in April 1939. Adolph Murie had a job to do. He had to find out why the park had fewer Dall sheep than it once did. He also had to say what to do about the wolves. Many people believed wolves were causing the Dall sheep population to shrink. Murie's findings reshaped how national parks manage wolves and other predators, and his work still informs park policy today.


Why the park service needed this study in the first place

For twenty years, the National Park Service thought that predators like wolves and coyotes were a problem that needed to be solved. They were caught, shot, or poisoned in the parks because they were seen as competing with deer and sheep that people came to see.

The Park Service's own history of science and natural resource management shows the agency tried to control predators from 1916 into the 1930s. By the time Murie went to Alaska, some predators had already disappeared from the parks, though the formal policy of predator control itself remained in place until Murie's findings helped bring it to an end.

Murie was already familiar with this issue. In 1937, he studied coyote ecology in Yellowstone National Park, sometimes collaborating with his half-brother Olaus, himself a biologist. Murie found that coyotes were not really hurting deer and elk populations. This earlier work was one of the reasons the National Park Service gave him a project in Alaska.

Two years of watching, not guessing

Murie spent the better part of two years observing wolves and sheep in the field, across two separate stretches. He relied on direct observation rather than guesswork. He went to the Denali backcountry and observed wolves and sheep. He collected scat and prey remains and listened to what ranchers and hunters said. Field records show his first field trip ran from April to October 1939. He returned in April 1940 and continued the study for another 15 months, concluding in July 1941. He saw them as animals, not just as threats, and this helped challenge stereotypes about wolves and influenced how they were managed.

Wolves were not the primary cause of the population crash

This was the discovery that changed the debate. Murie found that severe winter weather and starvation, combined with selective predation by wolves on the old and weak, were driving population trends. He also found that predators like wolves played an important role in the ecosystem. This discovery helped park managers justify ending predator control in Mount McKinley National Park.

In 1944, the National Park Service published his findings in the classic Fauna Series book titled “The Wolves of Mount McKinley”. It was an ecological study and one of the earliest detailed examinations of wolves and their relationships with other animals. Murie's work did not end wolf research in Denali. Later scientists built on his work by using airplanes and radio collars to study the wolves. Later scientists added detail to Murie’s findings, but the basic conclusion remained the same.

Why a 1939 field study still matters today

For readers following debates about wolves and predators, Murie's work is an important starting point. His two years in Denali helped the National Park Service move away from killing predators. More than eight decades later, Murie's study still offers an important lesson about understanding predators and their role in nature.