What Are the Fairy Circles in Namib Desert? Uncovering the Secrets of the Oldest Arid Place in the World

A new 'fairy circle' study may now have an answer to one of nature's greatest mysteries.

(Photo: Wikimedia Commons/ Olga Ernst & Hp.Baumeler)

Enduring Mystery of the Namib Desert

The Namib desert is one of the driest places on Earth, along southwestern Africa's Atlantic coast. In the local Nama language, Namib means "an area where there is nothing." This Martian-like landscape of lofty dunes, gravel plains, and rugged mountains stretches 50,331 miles (81,000 kilometers) across three countries.

This arid place is believed to be the oldest desert in the world, dating back at least 55 million years. It is also one of the most inhospitable places on Earth, with summer temperatures reaching 45 degrees Celsius and nights that can get below freezing. Yet, several species have adapted to call this desert home over time.

Namib desert has surprised experts with its many marvels, the most intriguing being its geomorphic phenomenon called "fairy circles." Also known as "fairy rings," these barren patches of sand are encircled by a single species of grass found throughout the Namib desert.

The rings are found in Namib's desert dunes and flat gravel plains, maintaining their near-perfectly circular shape in both terrains. In central Namib, the mysterious circles range from 4.9 to 19.7 feet (1.5 to 6 meters) in diameter. In northwestern Namibia, they are almost four times as large and can reach up to 82 feet (25 meters) wide.

For years, the fairy rings were thought to exist only in Namibia. In 2014, however, environmental scientist Bronwyn Bell found similar geomorphic formations in Western Australia while surveying the remote Pilbara region. Although the Australian circles closely resemble those found in Namibia, differences in their soil composition have further mystified scientists.

Meanwhile, the local Namibians have long been aware of the existence of fairy circles. The local Himba people believe that spirits cause these formations and are footprints left by their god, Mukuru. Some residents also believe these circles are caused by UFOs or fairies dancing at night.

Unveiling the Secrets of Fairy Rings

Mathematicians have also tried to build models to see if the fairy rings fit a recognizable pattern to understand their origin. To date, there is still no universally accepted theory as to the source of these curious patterns. In recent years, however, experts from Namibia, the U.S., Germany, and elsewhere have collaborated to study the phenomenon in hopes of better understanding it.

At the Gobabeb-Namib Research Institute, entomologist Eugene Marais explained that the leading theories originate from water scarcity in the Namib desert. Some studies suggest the circles are caused by termites, which cause them to harvest water and nutrients from the ground. These insects clear vegetation from the land, creating a barren space in the soil and allowing rainfall to seep deeper into the soil. This theory further suggests that termites stay hydrated year-round by drinking from these underground reservoirs.

The other central theory talks about "vegetation self-organization." It refers to root competition between the grasses, which causes bare patches to appear as reservoirs from which nutrients and water from the surrounding area are extracted. After years of drought, fairy circle grass can eventually dry up and disappear.