Photo credit: http://www.sxc.hu/
Most ants find their way around by leaving scent trails that show them or other ants how to find their way to food or back to their nest. While this works well in most environments, it doesn't work in sandy deserts where winds scatter the scent trails.
So how do desert ants get around? It's already known that ants can use celestial cues to generally orient themselves, but how do they know the exact right number of steps to take to get back home?
Harold Wolf and Matthias Whittlinger of the University of Ulm trained ants to walk across a patch of simulated desert to a food source. The ants were trapped and divided into three groups while they were eating. The first group was left alone. The second group had pre-cut pig bristles superglued to their legs, more or less putting them on stilts. The third group had their legs cut off just below the knees.
After they finished eating, the ants were released to go back to their nest. The regular ants easily found their way home, but the ants on stilts went right past their nest and looked around for their home. The ants with shortened legs stopped short of nest and seemed to search for their home.
The ants all walked the same number of steps, but since their gaits had been changed with the stilted ants taking giant steps and the ants with shortened legs taking small steps, only the regular ants could find their way back. Professor James Gould of Princeton, commenting on the experiment says "These animals are fooled exactly the way you'd expect if they were counting steps." [NPR]
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