Mental Floss

Scientists Identify the Creators of Namibia’s "Fairy Circles"

Kate Horowitz
Jen Guyton
Jen Guyton / Jen Guyton

There’s a lot to explore on this planet. For instance, fairy rings, which are weird bald spots that appear in African grasslands. On this front, a team of scientists have made some headway. They wrote about their findings in the journal Nature.

Jen Guyton

Scientists define fairy circles as evenly spaced, circular bald spots in areas otherwise covered by vegetation. The spots can be between 2 and 35 meters across and have so far been spotted in the grasslands and deserts in both Africa and Australia. The most famous fairy circles in the world can be found in a stretch of sandy soil in Namibia, where scientists have been trying to nail down a culprit for years.

There are currently two prevailing theories. The first is that the circles essentially make themselves when plants opt out of growing in these spots in order to out-compete other plants nearby. The second is that the circles are the product of underground activity by rodents, ants, or termites. Both theories make sense; plants have to be extra-strategic with their growth in dry regions, and many fairy circles abut termite mounds or anthills.

Ecologist Corina Tornita of Princeton University decided to put both theories to the test. She and her colleagues created computer simulations that incorporated just about every element of fairy circle existence: termite colony growth, mortality, rainfall, vegetation spread, root systems—you name it.

Tyler Coverdale

After crunching the numbers and reviewing the simulations, the researchers realized that neither theory was correct—at least on its own. Fairy circles required involvement from both plant and animal mechanisms to form.

The study authors say their results show that “interactions among social-insect colonies and vegetation can explain a diverse global suite of regular spatial patterns,” and that understanding weird natural phenomena will require considering a broad range of elements, including “behaviours and competitive dynamics of cryptic ecosystem-engineer species, the ways in which plants and SDF respond to bioturbation and climatic variability, and the movement of water through soil in different environmental contexts.” 

In other words: Even seemingly simple shapes are the result of complex networks, in which living and non-living things all influence one another. Some "fairies" are six-legged, some have roots, and others are made out of water or dirt, but it takes all of them together to make what looks like magic.