Thanks to deforestation, scientists have spotted an expanse of termite mounds in Brazil that are each about 2.5 metres tall, nine metres across, and regularly spaced across an area the size of Great Britain.
Described in the journal Current Biology, the mounds, still in use, are so large that they can be easily seen on Google Earth.
“This is apparently the world’s most extensive bioengineering effort by a single insect species,” says co-author Roy Funch of Universidade Estadual de Feira de Santana in Brazil.
“Perhaps most exciting of all, the mounds are extremely old — up to 4000 years, similar to the ages of the pyramids.”
Over thousands over years, the termites, from the genus Orthognathotermes, excavated roughly 10 cubic kilometres of soil while digging “a network of interconnected underground tunnels” and depositing the soil into these mounds.
Funch and colleagues estimate there are some 200 million mounds, which are located in the scrubby and thorny “caatinga” forests of northeastern Brazil, where 50% of the original tree cover has been altered for agriculture use, particularly pasture.
After being exposed, the mounds caught the eye of the scientific community.
The researchers speculated that the “strangely regular” pattern of the mounds could have been the result of competition between termites. But when they conducted behavioural tests, they found “little aggression at the mound level”.
Instead, they propose that the pattern is the result of “self-organisational processes”.
The reason behind the mound spacing remains a mystery, according to the researchers. They note that a queen chamber has yet to be found, so it is unclear how the colonies are physically structured.
“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,” says co-author Stephen Martin of the University of Salford in the UK.