According to a new study, led by Gabriela Prestes-Carneiro of Federal University of Western Para, Brazil, a network of fish ponds in the seasonal drylands of Bolivia supported a permanent human settlement about 1,000 years ago.
This research shows how exactly humans modified their environment to support themselves through the months-long Amazon Basin droughts.
Previous studies have found that humans settled the Llanos de Mojos region in central Bolivia — an area that experiences flooding rain from October to April and then drought throughout the rest of the year — around 500 AD.
These people built earthen mounds on which to settle, and built a series of shallow ponds, all connected by canals, in order to trap rainwater to last them through the dry season.
Prestes-Carneiro and her team conducted osteological and taxonomic identifications on the remains of over 17,000 fish at the most significant archaeological pond-based site in this region, called Loma Salavtierra.
They were able to identify over 35 different taxa of fish, with the majority being swamp-eels, armored catfish, lungfish, and tiger-fish. All of these species are adapted to live in low-oxygen, level-fluctuating waters — as was the case of the pond waters.