Circumstantial evidence suggests that archaic humans’ ability to cook food and consume more calories may have played a pivotal role in the development of much bigger brains as far back as Homo erectus more than a million years ago. But hard evidence for when exactly our ancestors fully wielded control of flames has proved elusive. A novel application of a trusty geochemical technique may help answer burning questions about when and where our ancestors made friends with fire.
…[Paleoecologist Kevin] Uno and colleagues turned to a class of polycyclic aromatic hydrocarbons (PAHs), a type of aromatic hydrocarbon that is produced when oil, gas, or wood is burned.
The team’s preliminary findings show elevated PAH concentrations around archaeological sites, whereas soil samples from nearby locations that show no signs of human habitation have lower PAHs—indicating that the fires were contained, not landscape-wide.