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The mysterious African "fairy circles" that appeared this week prompting extraterrestrial theories, has now been demystified and explained by scientists, according to a study published in Friday's edition of the journal Science. 

The strange rings of grass that covered the desert land in southwestern Africa, is actually the work of sand termites who engineered the rings to maintain a supply of water in their environment,  biologist Norbert Juergens of the University of Hamburg tells Science magazine.

Juergens has been studying fairy circles for many years, examining hundreds of them in detail. He goes on to describe how the termites (Psammotermes allocerus) first clear a patch of ground by eating the roots of short-lived, annual grasses.

Then the exposed, sandy earth then becomes an effective rain trap as this is no vegetation, water cannot be lost through transpiration. The invertebrates then go on to collect the water just below the surface where it can sustain the termites and a supply of perennial grasses at the margins of the circles.

.That water supply could be enough to keep the termites alive and active during the harsh dry season, while letting the grass survive at the circles' rims.

Juergens says this practice also drives wider benefits, with the insects becoming a valuable food resource for a whole range of other animals such as geckos, moles, aardvarks, jackals, spiders, ants and the like.

"We all admire the beaver for the way it can turn a linear river into a lake with a dam, but the termites turning the desert into a pattern of oases that allow permanent life even in drought periods for hundreds of years - that's much more fascinating," he told BBC News.

"What is more, these termites do it on a large scale - over hundreds of square kilometres. They should replace the beaver as the text-book engineer."

Fairy circles appear in a narrow belt that skirts the eastern edge of the Namib Desert from Angola to South Africa.