Circles in the sand

A dragon stirs deep under a desert. It slithers through the sandy dirt. It breathes a fiery, poisonous gas as it goes. The gas bubbles up to the surface. There, it burns circles of bare dirt in the grass. 

Or so one story goes. No one has seen this mythical beast. Yet some people in southern Africa say it’s there. It’s how they explain mysterious dirt circles that dot the eastern edge of the Namib Desert. 

Thousands of circles stretch as far as the eye can see. Some are small, just one meter (three feet) wide. Others are as wide as 50 m (164 feet). The dragon has been busy. 

for a Cause

Not everyone believes in dragons. Scientists have looked for other causes for the circles. Some think that, like the mythical dragon’s fiery breath, a gas bubbles up. Others think that ants may chew the roots of the grasses. Still others think that toxic plants may spread their poisons. Any of these actions could have the same effect. They could kill the grasses.

These are all theories, or ideas. They seem possible. Yet, scientists have to prove a theory before it’s accepted as fact.

Mysterious circles stretch as far as the eye can see.

Mysterious circles of bare dirt dot this desert on the west coast of southern Africa.



Norbert Juergens and his wife, Irmel, collect weather data near a circle.

Desert Discoveries

One scientist thinks he may have solved the mystery. Biologist Norbert Juergens has visited the desert 40 times. He’s studied 1,200 circles. He’s looked for patterns among the circles, trying to discover what they have in common.

The biologist sifted through the dirt inside the circles. He tested it for chemicals and measured how much water was in it. He recorded the animals he saw in the circles. He wrote down the names of plants growing nearby.

Common Clues

Juergens found some similarities with the circles. Each circle had dry, sandy soil in its center. He also found something surprising. Even in the dry season when it barely rains, the grasses around the circles stayed alive. To find out why, he dug deep into the soil. He discovered wet sand under each circle. The grass roots tapped into the water to keep the grasses alive.

Juergens also found sand termites. They tunnel through dirt and chew on plant roots. He studied these common clues. Then he came up with his own theory.

sand termites

Mystery Solved?

Juergens thinks that termites eat some grass roots. That kills the grass growing above the roots and forms a circle of bare dirt. When it rains, water soaks into the dirt. It’s saved in a pool under the dirt. The termites drink this water. The grasses around the circle soak it up. It’s how these insects and plants survive in the desert during the dry season.

Juergens will have to study more circles to prove if his theory is correct. While not fire-breathing dragons, these termites may have created one of nature’s mysteries.

A view from above shows circular patches dotting the land in the Namib Desert.