Who is making the mysterious "fairy circles" of Namibia?

In the Namib Desert, which runs through western Namibia, there are thousands of mysterious reddish circles scattered amid a sea of green grasses. Stories of a dragon with poisonous breath, gods leaving their footprints, fairies or other magical explanations are common among locals. Why do these circles appear? It’s been a mystery for nearly half a century.

These "fairy circles" can be a few meters in diameter and appear evenly spaced, forming a patterned landscape. This apparent high level of organization contributes to their mystery.

Over the years, scientists have crafted many hypotheses attempting to explain the origins of the circles. Perhaps they're patches of radioactivity? Maybe the plants are being eaten by underground termites? Or the dead plants are releasing toxic compounds? Perhaps the circles are merely the result of the plants competing for water and nutrients — a self-organizing pattern?

Many of these ideas did not make it past the thorough scrutiny of the scientific method. No radioactivity — or anything toxic, for that matter — was found in the soil inside the fairy circles. But what about the termites? That sounds plausible, right?

To test whether termites could be eating away at the plants inside the circles, scientists looked for signs of damaged plant roots inside the barren spots. The plants were clearly drying up, but no root damage was found. Their roots were even similar lengths to those outside the circles, proving that no termites or other animals were killing the plants.

It must be self-organization! When scientists measured the water content both inside and outside the fairy circles, they noticed that moisture close to the surface inside the circles quickly decreased after rainfall, while deep under the surface, a lot of water remained. The plants that compose the circles act like moisture vacuum machines, sucking dry any grass attempting to grow in the middle.

Researchers concluded that the formation of the evenly spaced fairy circles is the result of an adaptation technique deployed by the grass that forms the circles, which act as "ecosystem engineers", directly benefiting from the deeper water reservoirs provided by the plantless gaps. Similar patterns have also been studied in Australia.