Ants Count Their Steps

Source: Science
Ants can always find the way back to their nest. It was already known that they could determine the right direction by looking at the sky and the incidence of light. But how ants determine the distance to the nest was yet unknown.
Scientist of Ulm University (Germany) and Zurich University (Switzerland) have discovered how ants figure this out: by counting their steps.

The researchers got a group of ants to walk quite a distance in order to reach the food. When they arrived, their legs were either lengthened (with stilts) or shortened (by amputation) Next, the ants were allowed to walk back to their nest.
The animals on stilts all walked past the nest, while the ants with amputated legs stopped too early.
When the animals were allowed to cross the entire distance (to the food and back) with either legs that were too short or too long, they had no problem finding back their nest. From this, the researchers concluded that ants can count steps in order to determine distances.