Cataglyphis fortis, a Saharan desert ant travels long distances over sandy terrain, often completely devoid of landmarks, as it searches for food. They are able to return to their nest not by retracing their outbound path, but by using a direct route. They use light from the sky, but it seems they have a built-in pedometer that counts their steps and allows them to measure exact distances. An ant may travel 50 metres to catch an insect, tear a piece of the insect and carry it back to the nest through a hole often less than a millimetre in diameter.