VERIFIED FACT

Dung beetles can use the Milky Way to roll in a straight line.

Why this sounds fake

A galaxy feels far too faint and huge to be a practical compass for a small insect.

The Milky Way feels like a human-scale navigation cue, the kind of thing sailors, astronomers, or photographers notice. Nocturnal dung beetles use it too. Experiments with Scarabaeus satyrus showed that on moonless nights, the beetles could keep rolling straight when the Milky Way was visible, and lost that directional performance when the sky cues were blocked or altered. They are not reading constellations. They use the broad band of galactic light as a compass so they can escape the dung pile quickly with their prize. A tiny insect is using the galaxy as infrastructure.

The Surprise

With the Milky Way visible the beetle rolls dead straight; cover the sky and the same beetle loops in circles.

Top-down view of two circular dung beetle arenas side by side. The left arena, labelled with Milky Way visible, has a faint band of the Milky Way arching above it and a clean straight navy trail running from the centre of the arena out to the rim, ending in a small gold dung ball with a beetle pushing it; the verdict beneath reads rolls straight to the rim. The right arena, labelled sky cues removed, has a gray cap blocking the sky above it, and inside the arena the same beetle's trail is drawn as a red looping spiral that never leaves the centre area; the verdict beneath reads wanders in circles.
On moonless nights, blocking the sky breaks the beetles' straight-line rolling (Dacke et al., Curr Biol 2013).

1 discovery explored