Scientists in Sweden have found that dung beetles use the Milky Way to orientate themselves as they roll their balls of muck along the ground.
Moving in a straight line ensures they do not circle back to the dungheap, where other beetles might snatch their prized lump.
The scientists found during field experiments in South Africa that on cloudy nights the beetles wandered aimlessly - but when put in a planetarium showing the Milky Way, they regained their bearings.
"When the Moon is absent from the night sky, stars remain as celestial visual cues," the study's authors said in the report, which was published in Current Biology.
"Nonetheless, only birds, seals and humans are known to use stars for orientation.
"African ball-rolling dung beetles exploit the Sun, the Moon, and the celestial polarisation pattern to move along straight paths, away from the intense competition at the dung pile."
The report states that although it has been proposed before that insects use the stars as directional cues, it has never been proven.
The authors say dung beetles do not orientate with individual stars, but to the Milky Way.
"Even on clear moonless nights, many beetles still manage to orientate along straight paths," the reports said.
"This led us to hypothesise that dung beetles exploit the starry sky for orientation - a feat that has, to our knowledge, never been demonstrated in an insect.
"Dung beetles transport their dung balls along straight paths under a starlit sky but lose this ability under overcast conditions.
"In a planetarium, the beetles orientate equally well when rolling under a full starlit sky as when only the Milky Way is present."
