Research overview: El Jefe and jaguars in the Arizona borderlands

El Jefe was a male jaguar documented for years by remote cameras in the Santa Rita Mountains south of Tucson, one of very few jaguars recorded in the United States in recent decades. This overview describes how camera-trap detections, rather than collars, tracked his presence and movements near the northern edge of the species' range, and how he was later detected again in Mexico, implying substantial cross-border movement. His story highlights the precariousness of jaguar recolonization north of the border, the importance of transboundary connectivity, and the threat posed by border-wall construction to felid movement. The overview frames such individual male jaguars as sentinels of habitat linkage between core Mexican populations and historically occupied range in the American Southwest.