A Closer Look At Declining Yellowstone Wolf Numbers

Apr 29, 2019

Recent reports that the number of gray wolves in Yellowstone National Park has dropped caused concern among the animal's supporters, but the park's top biologist says there's no reason to sound the alarm. 

Doug Smith has led the Wolf Restoration Project at Yellowstone since its inception. He says populations can fluctuate for various reasons, but admits their numbers are currently about half of what they used to be.

"Our high point was 174 wolves in 2003, and last year's count was 80," says Smith. "Just because of accounting issues, it could have been 90, but that is still a decline, and that's primarily due to wolves equilibriating with their food source."

Smith explains wolf populations have held steady at around 100 for the past decade, and last year, a pack of 10 wolves in southern Yellowstone left the park's parameters and showed up in the state's count. 

Wolves continue to be controversial in Wyoming, especially for ranchers. Last year, 80 were killed by hunters, and an additional 50 wolves were put down by federal and state agencies due to conflicts with people.

The leading natural cause of death for wolves is other wolves. Smith says protected wolves in Yellowstone still have a 20% mortality rate because they are fiercely territorial. 

He adds wolves compensate for high death rates by breeding when they are young, and producing large litters.

"But that's an outgrowth of them living for millions of years at a high death rate," says Smith. "And so, 80% chance of survival for one more year sounds bad - but for them, it's kind of normal."

Yellowstone doesn't have a specific population goal for wolves, and it's National Park Service policy to allow nature to take its course. But Smith says excessive human-caused mortality is considered unnatural. 

He adds advocates for getting rid of wolves risk removing an animal that helps makes the region economically viable.

"Things like wolves, grizzly bears, and cougars is what makes this region unique," says Smith. "And it drives tourism, and tourism drives the economy. You know, not many other places in the United States has those big carnivores, and Wyoming's got 'em all."

In 1926, the last remaining wolf pack in Yellowstone was killed. In 1974, the gray wolf was listed as endangered, and wolves were reintroduced in 1996.