Before government-sanctioned bounties for gray wolves unraveled at the turn of the 20th century, as many as 2 million individuals roamed freely throughout North America. Hunted nearly to extinction as westward expansion ensued, population estimates for one of America’s top carnivores dropped to below 700 wolves by 1960.
Federal conservation initiatives driven by the Endangered Species Act have protected wolves, driving their population to an estimated 3,000 individuals today. But a decision by the U.S. Fish and Wildlife Service last year argued that gray wolves in the western U.S. no longer required federal protection.
Last week, a group of conservationists argued in Missoula before a federal district court that the service violated the ESA by inadequately considering challenges facing gray wolf survival, further petitioning that the species receive federal protections in the Northern Rockies.
Such protections were once guaranteed under federal law. In 1973, the ESA empowered the Fish and Wildlife Service to list a species as “endangered” if it is likely to become extinct in the near future, or “threatened” if it is expected to become endangered, both of which invoke certain protections. Five years later, gray wolves in the Lower 48, except Minnesota, were listed as endangered and today remain temporarily listed in the contiguous U.S. In Idaho, Wyoming and Montana, wolves are delisted and under state management.
However, in 2021, the Service determined that the nearly 3,000 wolves in the West are a sufficiently large, well-connected, and adaptable population, prompting a broader conversation surrounding the proposed nationwide delisting of the species.
Once spread across the continent, gray wolves occupy an estimated 10 percent of their historic range today.
During court proceedings on June 18, plaintiffs argued that in its decision FWS misapplied rules and did not accurately incorporate the best available science required under law, citing concerns over the wolf’s historic range, population size, genetic diversity, and ongoing human threats.
Wolves are peripatetic, meaning they travel from place to place in search of viable habitat and resources. Once spread across the continent, gray wolves occupy an estimated 10 percent of their historic range today. Conservationists argue that the agency’s analysis of the wolf’s range was based on contemporary, limited information focusing on a “single moment of time.”
In the face of ongoing stressors like habitat loss, dwindling genetic diversity, and human conflict, the plaintiffs further argued that FWS did not adequately estimate the minimum population size needed for long-term survival. It’s estimated that 85 percent of wolves in the west reside in the Northern Rockies, meaning there are just over 400 wolves across other western states. Mere dispersal is not enough to ensure the long-term survival of a species — individuals must also successfully find mates, establish territories and reproduce while avoiding human conflicts.
“In other words, an already bad and vulnerable situation for wolves is getting worse,” the plaintiffs wrote in their briefing.
A 2024 study written by Bridgett vonHoldt, an associate professor of ecology and evolutionary biology at Princeton University, was heavily cited during the hearing. As part of the research, vonHoldt conducted a population analysis determining that while gray wolf numbers are high enough to avoid inbreeding-related extinction in the near future, the species is still at risk of long-term extinction.
This analysis is based in part on the “50/500 rule,” a conservation concept that suggests a minimum of 50 individuals is needed to prevent inbreeding depression, or biological defects, in the short term and 500 to maintain long-term genetic diversity. (In 2014, another team of researchers argued that this rule required “upward revision” to a “100/1,000” rule.)
Considering the 50/500 rule, 2,950 wolves need to be on the landscape, while 5,900 are required to satisfy the more robust 100/1,000 rule. As of 2022, the most recently available data showed roughly 2,797 wolves distributed across 286 packs in seven western states, suggesting the number of breeders is well below the figures needed to maintain long-term survival.
An estimated 85 percent of wolves in the West reside in the Northern Rockies, meaning there are just over 400 wolves across other western states.
Changes in wolf management strategies in the Greater Yellowstone Ecosystem have further pushed wolves to their limits. Under state management initiatives, Idaho has committed to maintaining a baseline of 150 wolves, aiming to reduce the population from an estimated 1,150 to around 500. Similarly, Montana management strategies are committed to supporting 150 individual wolves with a “benchmark” goal of 450. Wyoming, by comparison, plans to maintain 100 wolves.
Both predator control and hunting threaten wolves across the GYE. Since 2011, an average of 75 wolves in Idaho have been killed each year, 61 in Montana, 47 in Wyoming, three in Oregon, and four in Washington. By comparison, during the 2022-23 hunting season alone, 400 wolves were killed in Idaho and 260 in Montana.
“The states are very capable of managing wolves in a scientific, data-driven, and publicly acceptable fashion,” said Doug Smith, retired senior wildlife biologist at Yellowstone National Park. “However, meddling from the Legislature jeopardizes the expertise of wildlife biologists, making baseless claims against wolves and requiring management actions not based on data or experience, or a majority of the public’s wishes. Some of these actions were voted down in Montana this last session, but not all, and should the states stay on this path, federal relisting certainly becomes a viable option.”
In his closing statement, Judge Donald Molloy said he would have a decision as soon as possible, potentially requiring the agency to reconsider threats to gray wolf populations.
