Experts have always known that African dung beetles use the sun and the moon as directional markers when rolling balls of dung containing their precious eggs away from other beetles.
But it had never been scientifically proven that the beetles ... sacred to the Egyptians as symbols of transformation ... used the Milky Way as a directional marker on moonless nights.
Dung beetles are known for rolling up balls of dung for later use as food and a depository for their eggs. Once they collect the dung, the beetles quickly roll the ball away from the dung pile to avoid having it stolen by other beetles. They do this by moving in a straight line.
With the dung ball deposited in a safe place, the eggs hatch into larvae which then metamorphose into winged beetles ... and fly off, soaring towards the warmth-giving sun. Thus, the scarab became associated in Ancient Egyptian mysticism with the transformation of base material into the divine. The Egyptian glyph for scarab beetle ... "kheper" ... means "transform".
The Egyptians also associated the scarab beetle with movements of the sun, moon and stars. While the link to the sun and moon were easily proved, scientists did not have proof of a link to the stars ... until now.
To test whether the beetles were using the stars as a navigational aid, scientists put the beetles into a dung-rolling course and filmed their behavior. The beetles were able to move in a straight line on moonlight nights and also on moonless nights when the Milky Way was visible.
When the sky was overcast, the beetles were unable to roll the dung balls in a straight line. When the beetles had tiny visors taped onto their heads to block their view of the night sky, they spent their time wandering aimlessly.
Next, they tested their speed on a 2 meter platform. On nights when the Milky Way was visible, the beetles were able to cross the platform in as little as 40 seconds. On cloudy nights, it took the beetles nearly 2 minutes to cross the platform.
Lastly, scientists tested the beetles inside of a planetarium. The dung beetles moved more efficiently when the ground was lit by the light of the Milky Way. When the ground was lit by the light of only a few bright stars, the beetles performed worse.
This research is believed to be the first study to document the use of the Milky Way for orientation in the animal kingdom.