Circles in the sand

A dragon lives under the sand in a desert. It breathes out a poisonous gas. The gas bubbles up. It burns circles of bare dirt in the grass. 

No one has seen this dragon. Yet, some people in southern Africa say it’s there. It’s how they explain the strange circles that they see. 

for a Cause

Scientists don’t believe in dragons. What else might cause the circles? Norbert Juergens wants to solve this mystery. He’s a biologist. He has studied 1,200 circles. He asks questions. What makes the circles the same? What makes them different from each other?

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

strange circles

Circles of bare dirt are seen in this desert in southern Africa.


Namib Desert

sand termites

Common Clues

He tested the dirt. He measured the amount of water in the dirt. He made a list of plants and animals in the circles. He charted the weather. 

Then he studied his data. He was looking for the things that made the circles the same.

Mystery Solved

Juergens found something surprising. In dry weather, the grass around the circles seemed healthy. He wondered why. Then he found wet sand under each circle. The water in the sand kept the grass alive. 

He also found termites under each circle. He thinks the termites eat the grass roots. That kills the grass. It leaves behind a circle of dirt.

When rain soaks into the dirt, the termites drink the water. The grass soaks up the water. That’s how the grass stays alive. Mystery solved!

A view from above shows the circles in the Namib Desert.