Stars and Species

Dung beetle rolling ball of dung at night

It is a cool, starlit night. Grains of sand shift ever so slightly on a breeze. The stars are bright, illuminating a small invertebrate body among the sand, delicate black shell and legs, it is rolling a ball of dung many times its size, two small horns protruding from its head pointed upwards. Pointed towards the dark hues, clouded purples, blues, shining specks, gradients of light, color and infinite intensity of the night sky. Deep in an African Desert, a dung beetle follows the stars.

Dung beetles use the light from stars and moon to orient themselves and find a point of reference to travel directly towards after finding a ball of dung, as a means to avoid traveling in a circle back to the area the dung was found, where they will likely encounter other beetles hungry for the food they have already secured. These remarkable little beetles are also able to use the muddled light from the Milky Way on moonless nights. They are one of many animal species known to use the stars for navigation. Humans have used the north star for thousands of years for sea-based navigation. Female sea turtles follow the reflection of the moon on the water at the horizon to guide them back to the sea after weeks spent incubating eggs on beachside shores. A series of tests by scientists studying the behavior of animals in planetariums modeling the real night sky has shown that several species, such as Indigo buntings and harbor seals, are able to track exact star patterns in the sky as a point of reference for navigation. If the scientists shifted sky simulation, the birds and seals shifted their path to follow the same set of stars. Harbor seals likely do this to help them find their way home after long hunting expeditions at night, left without physical landmarks and only the open sea. Indigo buntings use the stars to follow a set path during their annual migration from North America to breeding grounds in South America. Glass eels possess similar abilities, using the moon to navigate in a migration from their hatching as larvae in the Sargaesso sea to Atlantic waters closer to Europe, where they will travel upstream to estuaries and coastal environments and mature.

This navigation has immense benefits because it provides a secure method to geographically orient an animal and help them travel, whether it be to help find food, reproduction, or other migratory journeys. Using moonlight, starlight, the Milky Way as well as electromagnetic fields and olfactory sensing, to travel, thrive, and multiply across the globe. Whether it be the delicate, transparent body of a glass eel in starlit waters, or the shiny pointed black horns of a dung beetle pointed towards the Milky Way, celestial bodies have guided organisms on earth as long as we have had eyes to see and means to travel, an ever-present object of navigation, poetry, and myth. They tell us where we are in the galaxy as well as where we are on earth, forever a symbol of who we are and where we are going.