Looney Tunes would have you believe that the fastest animal in California is the aptly named Road Runner, closely pursued by its nemesis, Wile E. Coyote, but Jonathan Wright from Pomona College, USA, would like you to consider a much smaller creature. ‘Mites attain some of the fastest relative speeds documented in the animal kingdom’, say Wright and his colleagues, and when the team filmed their local mite, Paratarsotomus macropalpis, scuttling across hot concrete on a driveway close to the college campus, they were in for a treat. The tiny animals racked up top speeds of up to 0.26 m s−1. Scaling the speeds relative to the mite's diminutive body size, the team was truly astonished to see one youngster hit a blistering 323 body lengths (BL) s−1, leaving the previous world record holder – an Australian tiger beetle – in the dust at a trifling 171 BL s−1.
Impressed by the mite's agility, the team went on to scrutinise the arachnid's footwork, recording the mites’ stride frequency at a remarkable 135 Hz, which they say is the highest value reported for any weight-bearing muscle. And when they analysed the mites’ turning performance, they discovered that the mites used two strategies: a high-speed turn at approximately 795 deg s−1, where they pivot around the third inner leg as the claw at the end of the limb attaches to the surface like a grappling hook; and a slower turn at around 567 deg s−1, where they scuttle around a corner with the outer legs taking longer strides than the inner legs. Investigating the mites as they sprinted from a standing start, Wright and colleagues were also impressed to see the animals hit a respectable 0.15 m s−1 in just 15–20 ms, pulling accelerations of 7.2 m s−2 as they took off and decelerations of 10.1 m s−2 when they came to a standstill.
