The "Shadow Wolves" are a Native American tactical patrol unit assigned to Homeland Security Investigations (HSI) in Sells, Arizona located on the Tohono Oʼodham Nation that runs along the Mexico–United States border.

Tracking in hunting and ecology is the science and art of observing animal tracks and other signs, with the goal of gaining understanding of the landscape and the animal being tracked. A further goal of tracking is the deeper understanding of the systems and patterns that make up the environment surrounding and incorporating the tracker.