Sahara ant's speed defies belief

There's an ant in the Sahara that runs at 108 times its own body length per second. Scaled up to a human, that's almost 800 kilometres an hour.

It's the Saharan silver ant, Cataglyphis bombycina. The actual ground speed is modest - about 85 centimetres a second - but its body is only 8 millimetres long. In relative terms, it is one of the fastest land animals known, surpassed only by a few tiny invertebrates like the Californian coastal mite. Cheetahs manage about 16 body lengths per second. Usain Bolt, at peak, did six.

It has to move that fast because the surface of the Sahara reaches 70°C, hot enough to cook the protein in an ant's body within minutes. The silver ant waits inside its nest until the moment the desert is too hot for the lizards that would eat it, then bursts out, sprints across the sand for a few minutes, finds the corpse of an insect that has just died of heat, and sprints home. The entire foraging window is about ten minutes a day.

To survive it, the ant has triangular silver hairs all over its body that reflect sunlight like microscopic mirrors and radiate heat out the underside. It runs on six legs, using a tripod gait that becomes so fast the ant enters a full aerial phase where all feet leave the ground simultaneously. Its leg muscles fire so fast that all six feet leave the ground at the same instant - the ant is briefly flying.

It also navigates without scent trails. There's no shade, no landmarks, and the sun-baked sand erases pheromones instantly. Instead, the silver ant counts its own steps. Researchers studying related desert ants discovered that these insects navigate by counting their steps; when scientists glued tiny stilts to their legs, the ants overshot their nests.

There is, in other words, a tiny silver creature crossing the world's deadliest oven by doing mental arithmetic.