Resource Science: Science and management of wolves

The Western Livestock Journal frequently has articles about wolves and the Endangered Species Act (ESA) in the western states. WLJ editors Charles Wallace and Anna Miller Fortozo do a great job writing many of these articles making the complicated biology, law and politics of wolf and ESA management understandable. For example, Miller Fortozo’s article in the Dec. 1, 2025, WLJ describes proposed changes to ESA policy on critical habitat designations, interagency cooperation and threatened species protection. Articles in the Feb. 2, 2026, WLJ “Legal Ledger” describe that Colorado will not release any more wolves in the 2026 winter season, and there is a bill in Congress to remove the Mexican gray wolf from the ESA endangered species list.

Because wolves kill livestock and pets and the ESA is used to control land use including private property, these issues are important to agriculture and other natural resource industries (timber, mining, oil and gas). Despite WLJ’s fine efforts to make these issues understandable, the ESA in general, and wolves in particular, can be confusing. Most people aren’t going to understand what critical habitat and threatened species are, why Colorado isn’t releasing more wolves and why the Mexican wolf could be removed from the ESA. This is because legal cases are constantly changing these issues. But the basic science and management of wildlife should be understandable, especially for those who work on the land.

I’ve written about wolves and the ESA before (see the References at wlj.net) and here is a summary of the ESA and wolves as I understand it at this time. Recognize that these designations change with court cases and the subspecies and distinct population segment (DPS) designations are not scientifically definite.

The ESA allows listing of species, subspecies and populations called a DPS as endangered species. Science indicates that species are distinct types of animals like cattle, horses, dogs, elk, moose, etc. Subspecies and DPS are wildlife populations that differ from other populations of the same species in geographic range and traits like size, color and genetics. An example is the Mexican gray wolf subspecies in the southwest U.S. that is smaller than other gray wolves. It is important to recognize that Mexican wolves and other gray wolves are the same species, and that subspecies and DPS are simply populations in a specific area. I emphasize that subspecies and DPS are not scientifically definite because animals move over geography and time.

Gray wolves are a species that originally occurred across North America, and now occur in the western states, the states around the Great Lakes, Alaska and Canada. There are several subspecies and DPS of wolves that have been listed, or considered for listing, as ESA endangered species. As noted above, the subspecies and DPS designations described below are not scientifically definite.

The Mexican gray wolf in Arizona and New Mexico is listed as a subspecies under the ESA. The wolves in Montana, Idaho, Wyoming, eastern Washington and eastern Oregon are part of a Lower 48 states DPS and are not on the ESA list. They are the northern wolf subspecies and originated mostly from transplants from western Canada. Wolves in other western states are part of the Lower 48 states DPS and are on the ESA list. Wolves in Colorado originated from transplants from Oregon and Canada over the last few years, are the northern wolf subspecies, and are on the ESA list.

Wolves in the Great Lakes states (Minnesota, Wisconsin and Michigan) are part of the Lower 48 states DPS and are on the ESA list, although these designations have been challenged. The subspecies of Great Lakes wolves is uncertain. Wolves in Alaska are not on the ESA list. Wolves in southeast Alaska have been proposed for ESA listing as an endangered subspecies or DPS.

What does this mean? Wolves occur in populations in different areas that are considered separately under the ESA. This leads to scientific and legal debate over subspecies and population designations and whether they are endangered with extinction. But the wolf species is not endangered; they are common in Canada, Alaska, the Great Lakes states and the western states.

Regarding management, you know that managing livestock herds in different areas requires different management depending on range, winter weather, moisture, proximity to markets and other factors. This is also true for wildlife populations and is reflected in different management in your state’s game management units. But is it appropriate to use a federal law, the ESA, for managing wildlife populations, including wolves? I think it’s not. After all, it’s the Endangered Species Act, not the Endangered Population Act.

The ESA results in the federal government taking wildlife management authority from the states. This seems inappropriate for populations like subspecies and DPS considering “species” in the name of the ESA. The federal government can help states manage wildlife populations with funding and expertise, but in my opinion, should not contrive the ESA to take wildlife population management authority from the states. — Matt Cronin, WLJ columnist

(Matt Cronin is a biologist with Northwest Biology and Forestry Company LLC in Bozeman, MT, and a teaching professor at Montana State University. He may be contacted at croninm@aol.com.)