Mysterious Pattern in a Cave Is Oldest Rock Art Found in Patagonia

In the stark inland desert of Patagonia in Argentina, there is a remote cave decorated with nearly 900 paintings of human figures, animals and abstract designs. Until recently, archaeologists had assumed that the rock art at this site, known as Cueva Huenul 1, was created within the past few thousand years.

But in a paper published Wednesday in the journal Science Advances, archaeologists say that one of the cave’s most mysterious motifs, a comblike pattern, first appeared some 8,200 years ago, making it by far the earliest known example of rock art in one of the last places on Earth to be settled by our species. Cave artists continued to draw the same comb design in black pigment for thousands of years, an era when other human activity was virtually absent at the site. The cave art provides a rare glimpse of a culture that may have relied on this design to communicate valuable insights across generations during a period of climactic shifts.

“We got the results and we were very surprised,” said Guadalupe Romero Villanueva, an author of the study and an archaeologist at the Argentine government agency CONICET and the National Institute of Anthropology and Latin American Thought in Buenos Aires. “It was a shock, and we had to rethink some things.”

Patagonia, which spans the southern tip of South America, was not reached by humans until about 12,000 years ago. These early inhabitants thrived at Cueva Huenul 1 for generations, leaving signs of habitation.

Then, around 10,000 years ago, the area became more arid and hostile as a result of climatic shifts. The archaeological record in the cave likewise dried up for the next several thousand years, suggesting that the site was largely abandoned because of environmental pressures.

The comb motifs overlap with this long period of hardship, according to Dr. Romero Villanueva and her colleagues, who identified the age of the paintings with radiocarbon dating. The team also found that the black paint was probably made with charred wood, perhaps from burned shrubs or cactuses.

“As interesting as the ages are, for us it’s more significant that they span, more or less, 3,000 years of painting basically the same motif during all this time,” said Ramiro Barberena, an author of the study and an archaeologist also at CONICET in Argentina as well as the Temuco Catholic University in Chile.

He added that this was evidence “for continuity in the transmission of information in these very small and very mobile societies.”

Though the meaning of the comb motif has been lost to time, the researchers speculate that it might have helped preserve the collective memories and oral traditions of peoples who endured this unusually hot and dry period.

The relationships between groups of ancient humans that developed and shared such rock art may have enhanced the odds of survival in this challenging environment, Dr. Barberena said.

Andrés Troncoso, an archaeologist in the department of anthropology at the University of Chile who was not involved with the research, said he agreed with that interpretation. The paper “provides a contribution to the discussion about how humans have dealt with climatic change in the past,” he said.

Though the purpose of the comb motif is likely to remain a mystery, the motif’s persistent presence in the cave opens a new window into Patagonia’s prehistoric peoples.

“You cannot help but think about these people,” Dr. Romero Villanueva said, adding: “They were at the same place, admiring the same landscape; the people living here, maybe families, were gathering here for social aspects. It’s really emotional for us.”