Speedy elephants use a biomechanical trick to 'run' like Groucho

A study published in the April 3 issue of Nature solves a longstanding mystery about elephant speeds by clocking the animals at 15 miles per hour. That’s faster than reliable observations of 10 mph top speeds but slower than speculations of 25 mph. But do fast-moving elephants really “run”? Even at fast speeds, it might seem to the casual observer that elephants don’t run. Their footfall pattern remains the same as that in walking, and never do all four feet leave the ground at the same time – a hallmark of running. But biomechanists are finding that an elephant’s center of mass appears to bounce at high speeds. If that turns out to be true, an elephant’s gait meets the biomechanical definition of running.