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.