A cache of beautiful crystals collected 105,000 years ago in South Africa is shedding new light on the emergence of complex behaviours in our species.
A team led by Jayne Wilkins at Griffith University, Australia, discovered 22 distinctively shaped white calcite crystals at a site in the Kalahari desert called Ga-Mohana Hill North Rockshelter. “They are little rhomboids, really visually striking,” says Wilkins.
These geometric crystals didn’t originate at the site and haven’t been modified, so seem to have been deliberately collected and brought to the rock shelter for ornamental purposes. “They don’t seem to have been used for everyday tasks,” she says.
The collection of beautiful items seems like a normal thing for humans to do today, but this so-called symbolic behaviour only emerged around 100,000 years ago. “Collecting these kinds of pretty objects for non-utilitarian reasons could have its roots in symbolism and arts and culture,” says Wilkins.
Read more: Origin of our species: Why humans were once so much more diverse
Also found at the site were 42 fragments of burnt ostrich egg shell. The large egg shells may have been used by humans to store and transport water – offering more evidence of human innovation.
These discoveries in the Kalahari, 600 kilometres from the sea, are challenging the prevailing assumption that the emergence of complex behaviours like symbolism and technological innovation emerged at the coast, where humans had access to seafood containing nutrients thought to support brain growth.
Until now, the earliest evidence of symbolic behaviour was found at sites close to the sea, such as 100,000-year-old engraved ochre from Blombos cave and 60,000-year-old decorated ostrich egg shells from the Diepkloof rock shelter, both on the South African coast.
“In the Kalahari, which is really far from the coast, we are seeing the same kinds of behaviours, at the same time,” says Wilkins.
Journal reference: Nature, DOI: 10.1038/s41586-021-03419-0