Harald Wolf at the University of Ulm, Germany and colleagues wondered how desert ants can find their way back home. (Previously, scientists found that ants use the sun as a compass, but this would be useless in the desert).
When they shortened the ants' legs, the insects have trouble finding home. When they put stilts on the ants' legs, the insects traveled further and had to backtrack looking for home.
So, Harald and colleagues concluded that ants have an internal pedometer: they "count" (well, kind of) their steps!