Researchers working in the Horn of Africa have uncovered evidence showing how Middle Stone Age humans survived in the wake of the eruption of Toba, one of the largest supervolcanoes in history, some 74,000 years ago. The behavioral flexibility of these Middle Stone Age people not only helped them live through the supereruption but may have facilitated the later dispersal of modern humans out of Africa and across the rest of the world.
Excavations at a Middle Stone Age archaeological site, Shinfa-Metema 1, in the lowlands of northwest Ethiopia revealed a population of humans at 74,000 years ago that survived the eruption of the Toba supervolcano. The site was occupied during a time with long dry seasons, leading people to adapt by hunting animals that came to the remaining waterholes to drink, ultimately shifting their diets more heavily to fish as water sources diminished.
John Kappelman, a UT anthropology and earth and planetary sciences professor, and lead author of the study, explained, "Seasonal rivers thus functioned as 'pumps' that siphoned populations out along the channels from one waterhole to another, potentially driving the most recent out-of-Africa dispersal."
The research conducted by scientists at The University of Texas at Austin suggests that humans may have dispersed during arid intervals along "blue highways" created by seasonal rivers, challenging previous hypotheses that dispersals were restricted to "green corridors" formed during humid intervals. The study also unearthed stone tools that provide evidence of archery, with Kappelman noting, "Analyses show that the points are most likely arrowheads that, at 74,000 years in age, represent the oldest evidence of archery."
The behavioral flexibility displayed by the Middle Stone Age humans at Shinfa-Metema 1, in adapting to challenging climatic conditions such as the Toba supereruption, is believed to have been a key trait that allowed our species to disperse from Africa and expand globally.
The archaeological findings at Shinfa-Metema 1 indicate that the inhabitants hunted a variety of terrestrial animals and cooked their meals, as evidenced by controlled fire at the site. The discovery of small, symmetrical triangular points, believed to be arrowheads, sheds light on the advanced tool-making skills of these ancient humans.
The study contributes valuable insights into the survival strategies of ancient populations in the face of natural catastrophes and highlights the resilience and adaptability of early humans in navigating challenging environments to secure their existence and eventual dispersal across the world.