Research overview: VHF mortality sensors and cause-of-death investigation

Even in the GPS era, VHF remains indispensable for one task: signaling death. This overview describes mortality-mode beacons that change pulse rate when a collar stops moving for a set interval, alerting researchers to investigate. Rapid response lets teams reach a carcass before scavengers destroy evidence, enabling necropsy and determination of cause, whether vehicle strike, illegal killing, disease, intraspecific aggression, or starvation. For fragmented puma populations, such data revealed roads and human persecution as dominant mortality sources, directly informing crossing structures and policy. The overview also covers the homing fieldcraft required to locate a silent collar in difficult terrain. Cause-specific mortality from telemetry is a backbone of survival analysis and population viability assessment for cats.