A Vast Landscape of Termite Mounds Predating Ancient Rome Discovered From Space

A vast landscape of termite mounds that predate ancient Rome have been discovered in northeastern Brazil. Scientists estimate there are approximately 200 million mounds 2.5 meters (8.2 feet) high covering an area the size of Idaho. The amount of Earth moved would be equivalent to building 4,000 Great Pyramids of Giza—making it "the greatest known example of ecosystem engineering by a single insect species."

The termite mounds and their network of interconnected tunnels are still in use by the insects today. The termites have moved huge amounts of soil almost 4,000 years to create this landscape. Each mound is around 9 meters (29.5 feet) wide and is made up of around 50 cubic meters (164 cubic feet) of earth.

Details of the discovery were published in the Cell Press journal Current Biology. "These mounds were formed by a single termite species that excavated a massive network of tunnels to allow them to access dead leaves to eat safely and directly from the forest floor," study author Stephen Martin, the chair in social entomology at the University of Salford in the U.K., said in a statement.

The mounds are found in the thorny, semiarid forests that cover the region and are mostly hidden from view. However, as the land has been cleared for agricultural purposes, the mounds have become visible. As a result, scientists have been able to perform ground searches to analyze the mounds. They also used satellite images to work out how far the mounds span—around 89,000 miles.

Soil samples show construction of the termite mounds started 3,820 years ago and continued until the end of the Middle Ages. The regular spatial pattern does not appear to be the result of competition between termites in neighboring mounds. Instead, scientists think it is the result of resource availability. Termites appear to have used the tunnels to minimize the amount of time they spend traveling from one location to another. It also allows them to travel safely to find food.

"It's incredible that, in this day and age, you can find an 'unknown' biological wonder of this sheer size and age still existing, with the occupants still present," Martin says.

The mounds are reminiscent of the fairy circles found in Africa and Western Australia. These are circular patches of barren land that appear at regular intervals across grasslands. In Africa, they are a prominent feature of the Namib Desert. Scientists do not know exactly what causes these circles to appear, although a popular theory is that they are the result of termites feeding on the vegetation.