Millions of giant termite mounds in Brazil are visible from space

A new study reveals the existence of giant termite mounds large enough to be seen from space. These mounds are believed to have been deposited by termites during the process of creating underground tunnels. The structures cover a large area in Northeast Brazil, where the land is said to be "climatically stable" and seasonally dry.

These termite mounds date back as far as 4,000 years; they cover around 230,000 square kilometers of land in Northeast Brazil. According to the study, which was recently published in the journal Current Biology, the large structures aren't nests. Instead, researchers found that the mounds contain debris excavated from underground.

The study found that there are nearly 200 million conical termite mounds measuring 2.5m / 8.2ft in height and around 9m / 29.5ft. The excavation debris is substantial enough to be viewed from space using satellites. Based on samples taken from 11 mounds, the researchers estimate the fill dates as falling between 690 and 3820 years ago.

At those ages, the study says these termite mounds are akin to the oldest ever found, which are located in Africa. One of the most striking figures in the study is a frame of reference for the sheer quantity of dirt excavated by the insects: it's equal to about 4,000 great pyramids of Giza. As such, the scientists say this is the single greatest finding of an ecosystem created by a single insect species.

Some of these termite mounds have been cut open due to road construction, according to the study, which says that each mound was found to contain only soil. There are no internal structures in the mounds, though newer mounds have a central tunnel leading down to the termites' underground tunnel system.

Researchers ruled out the potential that these mounds serve as ventilation systems for the tunnels — they're not open to the outside world, the study reveals.