They call him El Jefe and he roams alone.
Pictures have appeared for years, just glimpses of the rare beast prowling the Santa Rita Mountains outside of Tucson. Then, on Wednesday, video surfaced and there he was for all to see in muscular motion — what some scientists say is the only wild jaguar known to be living the United States.
In three brief clips totaling about 40 seconds, the big cat ambles quietly through an arid forest and down a rocky stream, head down, in no hurry. El Jefe — "The Boss" — seems unaware of being watched.
"We use our specially trained scat detection dog and spent three years tracking in rugged mountains, collecting data and refining camera sites," Chris Bugbee, a biologist with Conservation CATalyst, the preservation group that captured the video, said in a statement released by the Center for Biological Diversity.
"These videos represent the peak of our efforts."
Aletris Neils, the executive director of the group, added, "We are able to determine he is an adult male jaguar, currently in prime condition. Every new piece of information is important for conserving."
Arizona historically has been near the northern end of jaguars' range, which stretches through Mexico, Central America and South America. The animals are listed as an endangered species in the United States and last year the Fish and Wildlife Service, urged by the center, set aside nearly 800,000 acres near Tucson as protected habitat.
These big cats — the only ones bigger are tigers and lions — were more plentiful before losing habitat to development and their lives to hunters. The last one legally taken was a female, shot in 1963.
Conservation groups on Wednesday pointed to the video of El Jefe as further reason to prevent the development of a planned open-pit copper mine in the Santa Rita Mountains. The area is also home to a smaller endangered cat; a lone male ocelot was photographed there in 2014.
"At ground zero for the mine is the intersection of three major wildlife corridors that are essential for jaguars moving back into the U.S. to reclaim lost territory," said Randy Serraglio of the Center for Biological Diversity. "The Santa Rita Mountains are critically important to jaguar recovery in this country, and they must be protected."
El Jefe was named last fall by students at Felizardo Valencia Middle School in Tucson, whose mascot is a jaguar.