From “Orientation of desert ants: Every cue counts” (EurekAlert!, 9-Mar-2012,PLoS ONE), we learn,
Desert ants use the polarized sunlight and count their steps in order to return to their home. Scientists of the Max Planck Institute for Chemical Ecology have now discovered that ants can also use magnetic and vibrational landmarks in order to find their nest. In addition, carbon dioxide produced by their nest mates’ breathing also helps to pinpoint their nest entrance. The desert ants’ navigational skills prove enormously adaptable to their inhospitable environment.
The individual ant isn’t smart. Even thecolony isn’t smart. It never has any new ideas.
So something is smart, it just isn’t the ants.