The real story
At a fresh dung pile, competition is fierce, and beetles steal each other's balls. So a roller shapes its ball and leaves in a straight line, the fastest way away from rivals. Before setting off, it climbs onto the ball and turns in a little 'dance' to get its bearings from the sky.
In 2013 a team led by Marie Dacke showed that the African species Scarabaeus satyrus still rolls straight on moonless nights. When the researchers fitted the beetles with tiny cardboard caps, they wandered in loops. In the Johannesburg planetarium, the Milky Way alone was enough to keep them straight. Dacke's team won an Ig Nobel Prize for it, and it was the first evidence of an animal steering by our galaxy.
