Termites in Brazil build an underground city the size of Britain

The termites of Syntermes dirus measure one centimeter, but they have created an underground network of tunnels for nearly four millennia.

The termites syntermes dirus measure one centimeter, but for nearly four millennia in Brazil they created an underground network of tunnels and whose excavations left 200 Millions of mounds of land on a surface the size of Britain.

" This is the largest known example of bioengineering and construction on the surface of the Earth by a single species – apart from the human being – and all by an insect about one centimeter in length, "explained AFP Roy Funch, a Brazilian naturalized American biologist.

The totality of this animal engineering work extends over an area of ​​230 000 km2, in northeastern Brazil. Funch and three other researchers, two Americans and one British, published their findings last week in the journal Current Biology. (Read: Brazil beats a record of deforestation)

According to the detail, the earth excavated by these patient insects to create such a structure is equivalent to "4000 pyramids of Giza ", also millennia in Egypt. The inhabitants of the place have always called "murundus" these mounds 2.5 meters high and about 9 meters in diameter, covered by the vegetation of the "caatinga", the semi-arid biome of the poor north-east. Brazilian.

But deforestation due to human action made termites more visible and the use of satellite images allowed us to determine the area that They cover. More than 90% belongs to the state of Bahia. "Then it became clear its extension and the scientific importance of the phenomenon," Funch adds.

The images disclosed in the study show vast expanses of land dotted with these nearly identical, uniformly distributed tapered buttes, separated by about 20%.

Geographer Eun-Hye Yoo of the State University of New York, helped to estimate the extent of the structure for the purpose of helping. satellite images. / Image taken from the study

The drawing of the city

To determine the antiquity of the … work, scientists took soil samples from eleven mounds and checked when it was the last time they were exposed to the sun. The oldest sample gave 3,820 years. These ages are comparable to those of the world's oldest termites in Africa, the publication says. (You can read: The report on climate change that crashed on Black Friday)

Now that determined that these termites were part of a large underground "city" The idea of ​​scientists is to continue to investigate its distribution and operation. It is known, for example, that termite mounds have a vertical tunnel that connects underground tunnels to the surface.

Instead, the mounds of soil that remain on the surface are simply the soil removed by termites for their work. " The mounds apparently do not have the function of housing termite nests .They only serve to remove the earth that termites dig, continually under the earth," Funch explains.

It is also known that these underground structures allow these insects to protect themselves from the "inhospitable (and dangerous) environment of the surface". According to the published study, tunnels never being open to the environment, so it is not a ventilation system, but it is A means of communication.

At night, when food is available, groups of 10 to 50 "workers" and "soldiers" emerge from the mounds through temporary tubes 8 millimeters in diameter, excavated from underneath. After being used, the temporary tunnels are hermetically sealed.

"We have no idea of ​​the architecture of these" cities "of insects, they must have a room for the queen, a nursery, spaces to store the food … and many tunnels linking everything, but everything is unknown to science, "adds the biologist. (Read also: UN promotes dialogue in Brazil on the protection of environmentalists)