In August of 2017, agents from the U.S. Fish and Wildlife Service killed a Mexican gray wolf (Canis lupus baileyi) in Arizona. Agents exercised “lethal control” because the wolf had attacked and killed at least two calves on a ranch in Apache County. The incident was significant because the Mexican gray wolf is one of the rarest and endangered mammals in North America.

The Mexican gray wolf is the smallest subspecies of gray wolf, weighing only 60–80 pounds, approximately the size of a German shepherd dog. These wolves once ranged throughout the American Southwest and central Mexico but by the 1970s were critically endangered. A captive breeding program began in 1977, with the last five remaining wolves in the species captured and sent to zoos to be bred and eventually reintroduced into the wild. In 1998, eleven wolves were reintroduced in Arizona by the U.S. Fish and Wildlife Service. Their numbers have grown since their reintroduction, but the subspecies remains endangered.

The killing of the Mexican gray wolf in Arizona illustrates the tension that often exists between the protection of endangered species and the protection of economic interests that can be threatened by the animals. In the Arizona case, attacks by the Mexican gray wolf on calves and cows threaten the livelihood of ranchers in the area.

On November 29, 2017, after decades of conflict, a new recovery plan for Mexican gray wolves was adopted. The plan’s goal is to have an average of 320 wolves in the wild for eight years before their protected status is lifted. In the meantime, park rangers, state and federal governments, and environmentalists will have to work together to implement measures that will protect both the wolves and ranchers’ investments.

  1. How did the U.S. Fish and Wildlife Service know which Mexican gray wolf had killed the cattle?

    • Answer

      The U.S. Fish and Wildlife Service monitors the wolves using GPS. Through an investigation, they were able to use the tracking data to determine which wolf was likely responsible.  

  2. The U.S. Fish and Wildlife Service gets complaints from both ranchers and environmentalists for their management of the Mexican gray wolf. What are some ways the two groups can work together to address everyone’s concerns?

    • Answer

      Answers will vary. Ranchers and environmentalists can both lobby the U.S. Fish and Wildlife Service to influence new rules and guidelines for the management of the wolves. Ranchers can implement measures that will help prevent the wolves from attacking their livestock. Fences can prevent the wolves from reaching the livestock. Range riders and guard dogs can scare off the wolves before they attack. Environmentalists can make concessions to ranchers, such as allowing wolves to be put down if they repeatedly attack livestock. 

  3. Do you think the Mexican gray wolf should have been killed for attacking ranchers’ livestock? Why or why not?

    • Answer

      Answers will vary. Some may argue that the wolves should not be killed because their population in the wild is so small. The wolves serve a purpose in the ecosystem by keeping elk and deer populations healthy and in check. Others may argue that killing the wolf was necessary because it had killed livestock multiple times and might continue to do so. Each cow or calf represents a significant investment for ranchers, so their loss can have a real economic impact.

captive breeding

reproduction of rare species controlled by humans in a closed environment, such as a zoo.


a disagreement or fight, usually over ideas or procedures.


organism threatened with extinction.


person who studies or works to protect the Earth's ecosystems.


having to do with a nation's government (as opposed to local or regional government).


system or order of a nation, state, or other political unit.

lethal control

killing of species whose populations have gotten too large or threaten livestock. Also called lethal predator control.


ability to economically support oneself.

park ranger

person who protects and informs the public about local, state, and national parks. Also called a forest ranger.


intentional return of an endemic species to its native range after it has been removed or in severe decline.


(subsp.) group of organisms within a single species, often distinguished by geographic isolation.