A radio-tracking system for wild animals

Cochran and Lord described one of the first practical VHF radio-tracking systems built for free-ranging wildlife, pairing miniaturized transmitters with directional receiving antennas to fix animal positions by triangulation. The work established the engineering conventions that telemetry biology would follow for decades: pulsed signals on assigned frequencies, hand-held Yagi antennas, and aerial tracking from light aircraft. Although demonstrated on smaller mammals, the design template was scaled up to fit collars on big cats within a few years. Understanding this foundational paper matters because every later GPS and satellite study of pumas, tigers, and snow leopards inherited its core idea: attach a beacon, listen for it, and turn signal direction into a map of where an animal goes.