Ancient snake drawings are among the largest known rock art worldwide

Prehistoric engravings of giant snakes along South America’s Orinoco river are among the largest examples of rock art we know of anywhere in the world, with some stretching for more than 40 metres.

The Orinoco is one of the world’s largest rivers, flowing through Venezuela and along its border with Colombia. “There’s an outstanding record of rock art along the Orinoco, especially on the Venezuelan side,” says José Oliver at University College London. “Usually, they are paintings found in rock shelters.”

Engravings are common in many open-air sites along the river, he says, but not all of them have been officially recorded.

Since 2015, Oliver and his colleagues have taken several trips to areas along the Colombian and Venezuelan margins of the river to build a better picture of its rock engravings.

“It wasn’t difficult to encounter new sites,” says team member Philip Riris at Bournemouth University in the UK. “Every time you go round a corner, there was always more.”

Of the 157 rock art sites that the team has managed to visit, 13 were made up of engravings that were at least 4 metres tall. “Anything that size is monumental in our view,” says Riris. “That means they’re often visible from quite far away, maybe 500 metres to a kilometre.”

Most of the engravings depict people, mammals, birds, centipedes, scrolls and geometric shapes, but snakes were among the largest motifs, with the biggest measuring 42 metres across. In the mythology of the Indigenous Orinoco people, anacondas and boa constrictors are primordial creators, so are held in high regard, says Riris.

The prominence of the rock art along the river suggests that the ancient carvings may have been a territorial marker to signal that a certain group lives there, but not necessarily a warning to stay away. “The engravings may not be exclusionary, but rather an inclusionary practice that was shared among the communities,” says Riris.

Ceramics unearthed in the region and dated to 2000 years ago have similar motifs to the ones on the engravings, which suggests that the rock art was similarly created two millennia ago.

The team hopes to discover even more of these carvings and collect clues about their origins and purpose. For example, many of them appear near rock shelters with burial grounds, which suggests they may be connected to ancient funerary practices.

“This is a valuable piece of research,” says Andrés Troncoso at the University of Chile. “It sheds light about the rock art of a non-well-known area of South America, continuing to fill up our knowledge of this region.”

“Euro-American minds often jump to the mammoths, cave lions and large mammals of Pleistocene cave sites in western Europe when they think of rock art,” says Patrick Roberts at the Max Planck Institute of Geoanthropology in Germany. “However, the giant snake engravings studied in the paper are some of the largest single rock art images anywhere in the world and come from the heart of a lowland tropical environment.”