But new research has shown that even insects have this ability. The noble Dung Beetle, famous for clearing the African continent of animal droppings, is able to navigate in the dark and roll its dung ball to a safe location.
Dung beetles rely on animal faeces, both as food and as a nest for their larvae. Many species of Dung beetle first form the dung into a ball, lay their eggs inside it, and roll it away from the main dung pile. They then bury it, and the larvae hatch and eat their way up to the surface.
But they do this around the clock and scientists had long wondered how they managed to steer in straight lines when there is no Sun to guide them. A group of researchers had found in 2003 that Scarabaeus zambesianus are able to maintain direction by using the polarised light of the Moon. However, many other species do quite well even on nights when the Moon is not visible. It was clear that they were using the stars, as they got lost when the skies were clouded over, but this left something of a mystery as the beetle’s simple eyes are too weak to distinguish individual stars.
But a combined team of Swedish and South African scientists seem to have found the answer: The Milky Way is not a point source, but provides a large gradient of light that dung beetles can see, and this allows them to maintain a constant direction as they roll the dung balls directly to their destination, even rolling directly over difficult obstacles rather than changing direction. They climb on top of the balls and perform a dance, during which they find the Milky Way and orient themselves. The direction itself doesn’t seem to matter, though, according to Marcus Byrne of the University of the Witwatersrand: “they just need to get away from the bun fight at the poo pile,” he says.