Santschi is known for his pioneering work on the navigational abilities of ants. In one experiment, he investigated the way harvester ants used the sky to navigate. He found that as long as even a small patch of sky was visible, the ants could return directly to the nest after gathering food. However, when the sky was completely hidden, they lost their sense of direction and began moving haphazardly. Some fifty years later Karl von Frisch found the explanation when he discovered that ants are guided by the polarization of light.