Hot springs may have been used by early human ancestors to boil food around 1.8 million years ago — long before they mastered cooking with fire, a study suggested.
The Olduvai Gorge in northern Tanzania has produced some of the oldest remains of early human ancestors known to date, along with some of the tools they used.
Researchers from Spain and the US have now found evidence that the rift valley also contained a number of hot springs near the sites of the early hominids.
This proximity, the team reported, raises the possibility that our distant relatives took advantage of the springs to boil kills like wildebeest, as well as roots and tubers.
Hot springs may have been used by early human ancestors to boil food (as depicted) around 1.8 million years ago — long before they mastered cooking with fire, a study suggested
'As far as we can tell, this is the first time researchers have put forth concrete evidence for the possibility that people were using hydrothermal environments as a resource,' said paper author and geobiologist Roger Summons of MIT.
In these settings, he added, 'animals would’ve been gathering and [...] the potential to cook was available.'
The researchers had originally set out to understand why a sandy layer of 1.7 million-year-old rock found as a 1.9 mile (3 kilometre) outcrop in the Olduvai Gorge was so strikingly different from the 1.8 million year old layer of dark clay it overlay.
'Something was changing in the environment, so we wanted to understand what happened and how that impacted humans,' said paper author and archaeologist Ainara Sistiaga also of MIT.
She collected rock samples from the gorge, which she analysed for the presence of certain lipids — a type of large organic molecule — that can provide signs of the kind of vegetation that would have grown in the region at the time.
It is thought that — around 1.7 million years ago — East Africa gradually dried up and, as a result, transitioned from a wet, tree-population environment to drier grasslands.
'You can reconstruct something about the plants that were there by the carbon numbers and the isotopes, and that’s what our lab specialises in, and why Ainara was