the strange rings of grass that cover great swathes of desert-margin land in southwestern Africa

"A German scientist thinks he can now explain the strange rings of grass that cover great swathes of desert-margin land in southwestern Africa.

These so-called fairy circles have variously been pinned on the presence of other, poisonous plants, on ants, and even toxic gases rising from below.

But Norbert Juergens says the one ever-present factor is sand termites.

The creatures have engineered the rings to maintain a supply of water in their environment, he tells Science magazine."

More info: http://bbc.in/16m5BmA