50 Years Later & Scientists Still Don't Know Why These Exist

TL;DR

Namibian fairy circles remain unexplained after 50 years because competing termite and plant-water-competition theories each have evidence for and against them.

Key Points

• 1.Fairy circles are a highly specific, unexplained phenomenon. Hundreds of thousands of bare circular patches, 2–35 meters wide, appear only in a narrow Namib Desert strip receiving 50–100mm of rain yearly, each circle consistently surrounded by about six neighbors.
• 2.The termite hypothesis proposes sand termites engineer the circles. First proposed in 2013, it argues termites eat grass roots to create underground water oases, then stop expanding when they meet rival colonies of equal size, forming a natural Demilitarized Zone.
• 3.The plant competition hypothesis argues grasses die off competing for scarce water. Bare patches form where competition is highest; dead-root zones allow groundwater to pool, creating reservoirs — which also explains why circles only appear in that specific rainfall band.
• 4.A 2017 study suggested both mechanisms work together. Simulations showed termite colony dynamics alone matched circle shapes, but reproducing the full grass-clump pattern between circles required adding water competition — yet this paper still didn't end the debate.
• 5.Discovery of similar circles worldwide deepened the mystery. Fairy circles were found in Australia in 2016 and a 2023 global survey identified hundreds of similar patterns across Africa, Asia, and Australia, suggesting multiple different causes rather than one universal explanation.