Taylor's treadmill menagerie.

A series of four papers in JEB in 1982, masterminded by C. Richard Taylor, asked two deceptively simple questions: why does running faster consume metabolic energy at a faster rate, and why do larger animals require less energy to transport each gram of tissue? The audacious goal of these experiments was to link the energetics and biomechanics of terrestrial locomotion. These were not the first studies to quantify how the energetics of locomotion change with speed and size, but they were the first to comprehensively explore why. Many of us are still working to answer those same questions, trying to follow the large footprints left by this magnum opus.