Dung beetles navigate using the Milky Way.
We tend to think of dung beetles as lowly creatures, right down to their name. In spite of their earthbound status, however, they do something downright cosmic that no other animal we know of does: navigate using the Milky Way. While “dancing” atop their balls of dung, they orient themselves by looking up at the night sky, catching a glimpse of the bright strip of light our humble galaxy generates, and then moving relative to its position. They do this by taking what scientists call “celestial snapshots” and storing the images in their tiny little dung-beetle minds, a surprisingly fast process that allows them to hightail it away from the dung piles they scavenge. (As for daytime gathering, they move using special photoreceptors in their eyes that allow them to see a symmetrical pattern of polarized light emanating from the sun.) Doing so quickly is imperative — there’s a lot of competition for dung out there, and daddy dung beetles need to move quickly to bury the excrement, which they later feed to their babies. The insects move rapidly in straight lines away from the dung piles, which seems to minimize the likelihood of meeting other creatures of the same kind and getting into a dung-related squabble.
There are around 8,000 species of dung beetles on Earth, 600 of which roll such balls; the others burrow directly beneath the piles of dung and store their quarry in tunnels. Most of them prefer the dung of herbivores, who tend not to digest their food that well. And while most dung beetles are lucky enough to live under dark skies that help them see the Milky Way, light pollution is a growing concern that could throw off their celestial compasses — that is, unless we become more considerate of our dung-rolling neighbors.
There are more than 350,000 known species of beetles, more than any other living organism — and it isn't even close. There are so many beetles, in fact, that they account for one out of every four animals on the planet. More amazing still, scientists think we’re under-counting our insect friends and that there could be as many as 3 million beetle species. They’re also found practically everywhere (once even in Antarctica), with British geneticist J.B.S. Haldane writing in a 1940 essay that “The Creator would appear as endowed with a passion for stars, on the one hand, and for beetles on the other.”
