Ants with stilts: An experiment

Alex Bellos writes:

In the first chapter of my book I mention experiments at the University of Ulm that discovered that Saharan desert ants have a sense of number. Researchers first sent ants down a tunnel for food. Once the ants reached the food some of the ants had pig bristles attached to their legs, as in the picture above. Others had their legs clipped shorter, and some were allowed to keep their legs as was.

It turned out that the ants with stilts overshot the distance home, and the ants with clipped legs undershot the distance. Only the ants with no modified legs got the distance right.

BONUS: See the scientists’ own description, in their study “The Ant Odometer: Stepping on Stilts and Stumps,” Matthias Wittlinger, Rudiger Wehner and Harald Wolf, Science, vol. 312, June 30, 2006, pp. 1965-7.