The ancient Egyptians believed that a dung beetle drove the movement of the sun. The dung beetle, or sacred scarab (Scarabaeus sacer), rolls its balls of dung across the ground in a straight line. And the ancient Egyptians believed sacred scarabs did so from east to west, the movement of the sun.
Today we know the ancient Egyptians were not so far off. The dung beetle is indeed guided by the sun, plus the light of the moon, and the light from the milky way. Roughly 600 of the 8,000-plus known dung beetle species roll such balls, for meals, gifts for potential mates or repositories for eggs.
As far back as the 400s, Egyptian scholar Horapollo described the beetle’s movement as rolling its ball from east to west, while looking east. It took until 2003 for Horapollo’s observation to be confirmed by modern scientific testing. When a team of entomologists placed five species of dung beetles in little arenas on farmland in South Africa, the creatures usually rolled dung balls in the direction of the sun as they attempted to make a straight line away from the dung source to a safe place to bury the dung ball and consume it in peace. To check that it was really the sun the dung beetles were following, the team reflected a sun off a mirror, while hiding the real sun from view. And just Horapollo would have hypothesized, the insects followed the reflected sun instead!
