The eruption of the Toba supervolcano in Sumatra approximately 74,000 years ago stands as one of the greatest natural disasters in Earth's history. Previous theories suggested this event was so devastating it nearly wiped out our ancestors. Some arguments even claimed the early human population plummeted to fewer than 1,000 individuals. However, recent findings from the Shinfa-Metema 1 archaeological site in the lowlands of Ethiopia provide a more optimistic view of human resilience.
Research published in the journal Nature indicates that humans did not succumb when the terrestrial environment became extremely arid. Through oxygen isotope analysis of ostrich eggshells and mammal teeth, the research team found evidence of severe drought shortly after Toba's volcanic ash reached the region. Despite these harsh conditions, the archaeological record at the site remains densely packed with stone tools, hearth remains, and animal bones. This suggests a continuous human presence.
Shifting Diets During Crisis
Data from the excavations reveal a drastic shift in the inhabitants' diet as a response to environmental stress. Before the supervolcano eruption, fish remains accounted for only about 14% of the total animal bone fragments. After the Toba ash altered the climate into a much drier state and rivers receded, the proportion of fish remains surged to 52%.
Rivers that fractured into small pools during the prolonged dry season actually provided an advantage for early humans. They could easily catch fish trapped in shallow water without needing complex fishing gear. Utilizing these river resources became the primary key for these human groups to remain in one location even as the surrounding landscape became increasingly difficult to inhabit.
In addition to fish, they consumed monkeys, antelopes, and other small animals. Evidence of cut marks and burned bones indicates that this food was processed and cooked at the settlement. This strategy proves that early humans possessed the practical intelligence to rapidly change their daily behavior for survival.
Weapon Innovation and New Migration Paths
Human resilience in Ethiopia was also supported by advancements in hunting technology. Researchers discovered many small triangular stone points believed to be the oldest arrowheads ever found. The use of bows and arrows provided high efficiency in neutralizing prey from a distance. This technology became crucial as food resources thinned and accuracy became more valuable than physical strength alone.
These findings also challenge old theories regarding human migration paths out of Africa. Previous models often emphasized that humans moved through lush green corridors during wet periods. However, the Shinfa-Metema 1 site shows that dry seasons and receding rivers could serve as "blue highways" for human movement. When food supplies in one pool were exhausted, groups would follow the riverbed to the next pool. This repeated pattern of small movements naturally led them further away from their original territory.
Reference: Kappelman, J., Todd, L.C., Davis, C.A. et al. Adaptive foraging behaviours in the Horn of Africa during Toba supereruption. Nature 628, 365–372 (2024). https://doi.org/10.1038/s41586-024-07208-3
