Ants walk using internal distance clock: study

CBC News: Ants walk using internal distance clock: study: "Foraging Sahara Desert ants wander when searching for food, but take a relatively straight path when heading back to their nests.

To do so, the ants need to judge directions and distances when travelling over flat, sandy terrain without landmarks. Scent trails used by other species won't work because the odours fade in the hot desert."