Google Earth Blog

The amazing things about Google Earth


fairy circles

Fairy Circles in South Africa

We recently took a trip from Cape Town to the Northern Cape Province in South Africa and on the way noticed what looked like patches of bare ground or nearly bare ground:

The above are photos we took, but you can also explore the region in Street View.

This reminded us of Fairy Circles, a phenomenon in Namibia. Last time we looked at Fairy Circles we also noted a similar phenomenon in Australia. We have also seen similar patterns around the world created by ants and termites. And in South America we looked at patterns that are apparently created by worm poo.

At the time, we did not think to try and find one near the road and see if we could see any ant activity. Once we got back from the trip we had a look in Google Earth and found the patches are even more visible from above and cover a vast region:

We believe these circles are created by ant or termite colonies. They can even be seen in cultivated fields, which suggests the soil is permanently changed. The Namibian and Australian fairy circles are found mostly on very flat land and scientists believe water plays a role in their formation. However, these ones can be seen on hillsides and slopes and seem to be stopped only by extremely rocky ground.

In most cases, the spots consist of areas of reduced vegetation, but in some places the pattern seems to be reversed, with more vegetation in the spots:

In some cases there are bare rings:

For the locations of some of the screenshots above see this KML file. But be sure to explore more as they cover a vast region.

Seeing worm poo from space

We recently came across this interesting article about a South American phenomenon of mounds known as surales. Apparently scientists have demonstrated that they consist largely of earthworm excrement and are created by the earthworms. The patterns they produce are reminiscent of fairy circles and ant and termite cities that we have covered in the past.

We tried looking for the surales, but they proved quite difficult to find. We found places we thought might be surales but had no way of confirming they were not termite mounds or just small bushes. In one case we even found a hopeful location with Street View but we could see termite mounds in the Street View.


Possibly a mix of surales and termite mounds

Luckily, we came across this article, which includes a video of one of the scientists using Google Earth to show off some of the locations.

Surales come in a variety of sizes:

It is difficult to distinguish them from termite mounds, and sometimes they occur together:

Surales on the left, termite mounds on the right.

Surales form a variety of patterns:

The original science paper can be found here

For the above locations and more from the video, download this KML file.

Fairy circles

In January we had a look at ant and termite colonies as seen from space. In that post we mentioned the phenomena of Fairy Circles from Namibia. Fairy Circles are regular patches of bare ground in the grasslands of Namibia as seen below


Fairy Circles in Namibia

A similar phenomenon has now been found in Australia. Read more about it here. This is what they look like in Google Earth:


Fairy Circles in Australia

There is Street View going through the area in Australia with Fairy Circles and you can see them along the sides of the road.

There has long been controversy over the origin of the Namibian Fairy circles, but the Australian scientists are fairly sure that the circles arise from feedback mechanisms related to plant growth and water run-off. They also predict that such patterns will arise in other parts of the globe with semi-arid conditions. So, we thought we would have a look and see if we could find any more examples.

The closest we have found so far are:


Somalia.


Burkina Faso.


Senegal.

The above patterns occur over vast areas. They are not quite the same as fairy circles and we could not find any ground level photos.

We also came across this interesting pattern in Australia:

Fairy Circles are patches of bare ground in grassland. This looks like patches of grass in bare ground.

To find all the above locations in Google Earth download this KML file. We have also included the locations from the ‘Ant Cities’ post as the patterns are remarkably similar.

Ant Cities from Space

We recently came across this article about an area near the Grand Canyon where you can see circular patches of bare ground in the imagery. The bare patches are believed to be caused by ant nests and so the area has been dubbed the ‘Las Vegas of Ants’.


‘Las Vegas of Ants’, Grand Canyon, Nevada, USA.

Another location that has similar patterns that may be caused by ants is an area in Namibia. There they are known as ‘fairy circles’.


Namib fairy circles.

In Zambia there are large regions that are covered with termite mounds. Although termites look, and behave like ants they are actually more closely related to cockroaches. If you look at the region around Choma, in Southern Zambia, you will notice that all the fields have trees speckled around them, but it is not obvious why from the satellite imagery. However, there is a higher resolution image from the Africa Megaflyover


Termite mounds near Choma, Zambia. According to my sister, a biologist, the termite in question is Macrotermes sp.

Where farmers are using centre-pivot irrigation it is necessary to flatten the termite mounds, but the marks where they were can still be seen in the fields.


Top: a field with uncut trees where the termite mounds are. Centre: uncleared bush with termite mounds showing as lighter patches. Bottom: Circular fields for centre pivot irrigation with termite mounds flattened.

We also came across an area near Choma which has some white dots in the soil that are smaller than the previous termite mounds.


According to my sister, these could be another type of termite (possibly Cubitermes sp.), which makes small grey mounds.


An area near Lochinvar National Park, Zambia. This image was captured during a fire (still burning at the top right) which makes the termite mounds really stand out.

Large termite mounds are common in other countries such as India and Australia. We couldn’t find any that were clearly visible in satellite imagery but we did find this one, known as a cathedral termite mound, in Street View:


A cathedral termite mound, Litchfield Park, Australia

If you look at the satellite view of the area you can just make out some lighter spots in the imagery, which are other cathedral termite mounds and when they are close to the road you can also see them in Street View.

When looking around Namibia we came across some other strange patterns:


Strange patterns that appear to be related to water flow.

We also came across a location in Ethiopia that is featured in Google’s ‘Earth View’ Chrome extension. It also shows dots all over the fields that might be termite mounds but we could not find any ground level photos to confirm it.


Near Tana Lake, Ethiopia

To see all the locations featured in this post in Google Earth download this KML file.