Adaptive foraging behaviours in the Horn of Africa during Toba supereruption

Authors:

John Kappelman, Lawrence C. Todd, Christopher A. Davis, Thure E. Cerling, Mulugeta Feseha, Abebe Getahun, Racheal Johnsen, Marvin Kay, Gary A. Kocurek, Brett A. Nachman, Agazi Negash, Tewabe Negash, Kaedan O’Brien, Michael Pante, Minghua Ren, Eugene I. Smith, Neil J. Tabor, Dereje Tewabe, Hong Wang, Deming Yang, Solomon Yirga, Jordan W. Crowell, Matthew F. Fanuka, Teshager Habtie, Jayde N. Hirniak, Carla Klehm, Natalia D. Loewen, Sahleselasie Melaku, Sierra M. Melton, Timothy S. Myers, Sarah Millonig, Megan C. Plummer, Keenan J. Riordan, Nicholas A. Rosenau, Anne Skinner, Abraham K. Thompson, Lindsey M. Trombetta, Adrienne Witzel, Ephrem Assefa, Maria Bodansky, Ayenachew A. Desta, Christopher J. Campisano, Daniel Dalmas, Connor Elliott, Metasebia Endalamaw, Nicholas J. Ford, Frederick Foster, Tomas Getachew, Yibai Li Haney, Brittney H. Ingram, Jonayah Jackson, Curtis W. Marean, Sissi Mattox, Karla de la Cruz Medina, Gebretsadkan Mulubrhan, Keri Porter, Alexis Roberts, Perla Santillan, Alaric Sollenberger, Julia Sponholtz, Jessica Valdes, Lani Wyman, Meklit Yadeta & Sierra Yanny

Abstract:

Although modern humans left Africa multiple times over 100,000 years ago, those broadly ancestral to non-Africans dispersed less than 100,000 years ago¹. Most models hold that these events occurred through green corridors created during humid periods because arid intervals constrained population movements². Here we report an archaeological site—Shinfa-Metema 1, in the lowlands of northwest Ethiopia, with Youngest Toba Tuff cryptotephra dated to around 74,000 years ago—that provides early and rare evidence of intensive riverine-based foraging aided by the likely adoption of the bow and arrow. The diet included a wide range of terrestrial and aquatic animals. Stable oxygen isotopes from fossil mammal teeth and ostrich eggshell show that the site was occupied during a period of high seasonal aridity. The unusual abundance of fish suggests that capture occurred in the ever smaller and shallower waterholes of a seasonal river during a long dry season, revealing flexible adaptations to challenging climatic conditions during the Middle Stone Age. Adaptive foraging along dry-season waterholes would have transformed seasonal rivers into ‘blue highway’ corridors, potentially facilitating an out-of-Africa dispersal and suggesting that the event was not restricted to times of humid climates. The behavioural flexibility required to survive seasonally arid conditions in general, and the apparent short-term effects of the Toba supereruption in particular were probably key to the most recent dispersal and subsequent worldwide expansion of modern humans.

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