Who draws the Namib Desert's 'fairy circles': termites, or the grass itself?
Across a 2,400-kilometre strip of the Namib, grasslands are dotted with bare circles 2 to 12 metres wide, fringed by taller grass and spaced with uncanny regularity. Similar patterns were found in Australia in 2014. For decades, scientists have argued over whether termites or the grasses themselves make them.
Fairy circles run in a band about 160 kilometres inland, from Angola down to South Africa's Northern Cape, and also occur in part of the Pilbara in Western Australia. Each circle seems to have a life cycle of some 30 to 60 years: it becomes noticeable at about 2 metres across, can widen to around 12, and is eventually reclaimed by grass. Local traditions have their own explanations; in Himba stories they are footprints of the gods, and the Himba use their grassy rims for grazing.
One camp blames termites. In 2013 Norbert Juergens reported finding the sand termite Psammotermes allocerus in 80 to 100 per cent of circles and in every newly formed one. He proposed that the termites kill the grass, leaving bare ground through which rain soaks deep and is stored, feeding the ring of grass at the edge, which the termites then eat, rather like beavers engineering their own habitat. Critics replied that he had confused correlation with causation, and Namibia's leading termite expert, searching specifically, did not find sand termites so widespread.
The other camp says the grasses organise themselves. In very dry places plants compete fiercely for water; bare patches collect rain that flows out to the roots at the edge, strengthening the ring and keeping the centre bare. Circles are commoner where rainfall and soil nutrients are lower, and their strikingly regular spacing matches the mathematical 'Turing' patterns of self-organising vegetation rather than the layout of termite nests. A 2022 study dug up hundreds of grasses and found those inside circles had died of water stress while their roots were still intact, arguing against termites. In 2024 researchers showed that seedlings in circles quickly dry out and die.
In a 2025 review, Michael Cramer and Walter Tschinkel concluded that vegetation self-organisation is the only explanation consistent with all field observations. Circles in different places may still form differently. In Australia, some patterns once linked to fairy circles turned out to be termite nests the Martu people call linyji, while the true Australian circles appear to result from hard clay crusts forming on bare soil.
Source: Wikipedia — Fairy circle (arid grass formation) · Text summarised from Wikipedia (CC BY-SA 4.0)
