Ancient human faces and other figures carved into stone have emerged from the Amazon River as a historic drought in the Brazilian region has brought water levels to record lows. The rock carvings depicting animals and other natural forms have been uncovered on the shores of the Rio Negro at an archaeological site called Ponto das Lajes, which means “Place of Slabs.” Researchers estimate that the markings are between 1,000 and 2,000 years old.

“The engravings are prehistoric, or precolonial. We cannot date them exactly, but based on evidence of human occupation of the area, we believe they are about 1,000 to 2,000 years old,” archaeologist Jaime de Santana Oliveira said in an interview on Monday.

“Some rock carvings had been sighted before, but now there is a greater variety that will help researchers establish their origins,” he added.

One area shows smooth grooves in the rock, thought to be where Indigenous inhabitants once sharpened their arrows and spears long before Europeans arrived.

Mr Oliveira said the carvings were first seen there in 2010, but this year’s drought has been more severe, with the Rio Negro dropping 15 metres (49.2 feet) since July, exposing vast expanses of rocks and sand where there had been no beaches.

“This time we found not just more carvings but the sculpture of a human face cut into the rock,” said Oliveira, who works for the National Historic and Artistic Heritage Institute (IPHAN), which oversees the preservation of historic sites.

(With inputs from Reuters)