At the base of a brush-covered hill in South Africa’s Northern Cape province, a massive stone outcropping marks the entrance to one of humanity’s oldest known dwelling places.
Humans and our apelike ancestors have lived in Wonderwerk Cave for 2 million years — most recently in the early 1900s, when a farm couple and their 14 children called it home.
That process led to the emergence of Homo habilis, the first creature generally regarded as human, 2.3 million years ago. Its brain was up to twice the size of its predecessor’s, its teeth were much smaller, and its body was quite similar to ours.
Wrangham credits the transformation to the harnessing of fire.
At Koobi Fora and Chesowanja, both in Kenya, small patches of reddened soil were found in areas containing stone tools up to 1.5 million years old.
To try to prove that Early Stone Age campfires caused the discoloration, researchers in the 1980s and ’90s used techniques such as magnetic susceptibility analysis and thermoluminescence dating.
In recent decades, a number of sites have vied for the title of earliest human-controlled fire.
Researchers weren’t looking for signs of prehistoric fire; they were trying to determine the age of sediments in a section of the cave where other researchers had found primitive stone tools.
In the process, the team unearthed what appeared to be the remains of campfires from a million years ago — 200,000 years older than any other firm evidence of human-controlled fire.
Their findings also fanned the flames of a decade-old debate over the influence of fire, particularly cooking, on the evolution of our species’s relatively capacious brains.
At Wonderwerk, Boston University archaeologist Paul Goldberg — a specialist in soil micromorphology, or the small-scale study of sediments — dug chunks of compacted dirt from the old excavation area.