A rare jaguar roams Arizona. Border wall expansion imperils its future.

A rare sight was captured by a night-vision trail camera in July: a grown jaguar, roaming through southern Arizona.

Researchers at the University of Arizona’s Wild Cat Research and Conservation Center call him Jaguar Number Four, a big cat that roamed across the United States-Mexico border through the San Rafael wildlife corridor. As of July 4, the same cat has been detected five times by cameras placed south of Tucson, said Susan Malusa, director of the Wild Cat Center.

The sightings excited the Wild Cat Center’s team, as it showed the wildlife corridor had not yet been interrupted by the southern border wall, which partially bisects the sprawling grasslands and woodlands that ocelots, mountain lions, bobcats and, yes, even jaguars, traverse.

However, the researchers’ fears have not completely abated, as construction on a 27 mile segment of the wall is estimated to begin in late August under the Trump administration’s efforts to crack down on migrant crossings.

Jaguar Number Four is photographed July 1 in a forested area near southern Arizona. Photo credit: University of Arizona’s Wild Cat Research and Conservation Center

Two environmental groups, the Center for Biological Diversity and Conservation CATalyst, filed a lawsuit July 9 against Homeland Security Secretary Kristi L. Noem over the expansion. The lawsuit challenged Noem’s authority to waive “bedrock environmental protections” to quicken construction, arguing that it would destroy the “border’s last remaining significant wildlife corridor.”

“It would certainly be an existential threat to the natural recovery of jaguars north of the border,” said Russ McSpadden, a southwest conservation advocate at the Center for Biological Diversity.

The Department of Homeland Security did not respond to a request for comment Saturday.

About 100 years ago, evidence shows that jaguars reached as far as the Grand Canyon, Malusa said. However, hunting and habitat fragmentation - which can mean the construction of towns, houses, and also border walls that break up natural environments - has reduced the jaguar population and the range at which they roam.

So when researchers see male jaguars trekking into southern Arizona, it’s a positive sign that the ecosystem is able to support everything from “the smallest herbivores to the largest apex predators,” Malusa said.

The San Rafael Valley has not seen an active breeding population among jaguars in about 60 years, said Roberto Wolf, the Mexico general manager of the Northern Jaguar Project. The last female jaguar known to be in Arizona was killed around 1965, Wolf said. Female jaguars tend to take longer to leave an area.

Upon the expansion of the border wall, any jaguars south of the border would be unaffected, Wolf said. But jaguars north of the border, which could still include Jaguar Number Four, would be unable to travel to Mexico and eventually die as the last of its kind in the U.S.

Jaguar Number Four’s presence in southern Arizona traces to 2023, with some photos identifying him as early as spring 2023. He popped up in the months after a shipping container border wall ordered by former governor Doug Ducey (R) was dismantled after an agreement with the Biden administration and intense criticism from environmentalists, local residents and officials.

In May 2024, students and tribal members from the Tohono O’odham Nation named the jaguar “O:ṣhad Ñu:kudam,” meaning “Jaguar Protector” in the O’odham language.

The jaguar traveled down to Mexico sometime in late 2023 or early 2024 and appeared to stay there for an extensive period of time, Wolf said. Then he came back. Jaguar Number Four’s earliest sighting this year was June 24, Malusa said.

The latest detection was July 4, but because the Wild Cat Center’s volunteer researchers have to manually visit the trail cameras in oftentimes rugged terrains, researchers did not learn about it until Aug. 2. On that day, Malusa said volunteer Tim Cook texted her, “We got him.”

The image captured was of Jaguar Number Four, staring right into the camera. Another image, dated to July 1, captured a full-body photograph of the jaguar passing through a forested landscape.

Ever since Jaguar Number Four’s return to Arizona, there have been no attacks on cattle and no human encounters, Wolf said. It signifies that the habitat still has “enough wild prey to hold such an animal,” he said.

Jaguar Number Four’s return to the U.S. could also mean that he found the environment suitable to live in. If the circumstances did not meet the jaguar’s criteria, Wolf said the big cat likely would have never returned.

Researchers and environmentalists hope for the long-term repopulation of the big cat, which is an endangered species. But if the border wall were to expand, Wolf said signs point to that being the “nail in the coffin for the jaguar in the U.S.”