There are many dung beetles competing for a limited amount of food at a dung pile, so whenan individual is finished rolling a ball of dung it is in its best interest to make a quick escape.And the fastest way to travel is in a straight path. Scientists noticed that when the moon wasvisible, these dung beetles did just that; they traveled in straight paths. But when it was acloudy night, the beetles' paths became shaky and erratic.
To be sure the beetles were indeed using the moon's polarization and not the moon itself, theresearchers used a filter that changed the pattern of the polarized moonlight by 90 degrees.The beetles responded by changing their course by 90 degrees.