Early Modern Humans Cooked Starchy Food 170,000 Years Ago

The discovery also points to food being shared and the use of wooden digging sticks to extract the plants from the ground by early modern humans. Professor Lyn Wadley, a scientist from the Wits Evolutionary Studies Institute at the University of the Witwatersrand, South Africa (Wits ESI), said:

Dr. Christine Sievers, a scientist from the University of the Witwatersrand, who completed the archaeobotanical work with Wadley, added:

The underground food plants were uncovered during excavations at Border Cave in the Lebombo Mountains (on the border of KwaZulu-Natal Province, South Africa, and eSwatini [formerly Swaziland]), where the team has been digging since 2015.

This discovery is much older than earlier reports for cooking similar plants and it provides a fascinating insight into the behavioral practices of early modern humans in southern Africa. (Image: Wits University)

During the excavation, Wadley and Sievers recognized the small, charred cylinders as rhizomes. All appear to belong to the same species, and 55 charred, whole rhizomes were identified as Hypoxis, commonly called the Yellow Star flower. Sievers said:

The Border Cave plant identifications were made based on the size and shape of the rhizomes and on the vascular structure examined under a scanning electron microscope. Modern Hypoxis rhizomes and their ancient counterparts have similar cellular structures and the same inclusions of microscopic crystal bundles, called raphides.

The Border Cave plant identifications were made based on the size and shape of the rhizomes and on the vascular structure examined under a scanning electron microscope. (Image: Wits University)

The features are still recognizable even in the charred specimens. Over a 4-year period, Wadley and Sievers made a collection of modern rhizomes and geophytes from the Lebombo area. “We compared the botanical features of the modern geophytes and the ancient charred specimens, in order to identify them,” explains Sievers.

Hypoxis rhizomes are nutritious and carbohydrate-rich with an energy value of approximately 500 KJ/100 g. While they are edible raw, the rhizomes are fibrous and have high fracture toughness until they are cooked. The rhizomes are rich in starch and would have been an ideal staple plant food. Wadley said:

Wooden digging sticks used to extract the plants from the ground

Co-author of the paper and co-director of the excavation, Professor Francesco d’Errico, said:

The plants were cooked and shared

The Hypoxis rhizomes were mostly recovered from fireplaces and ash dumps of early modern humans rather than from surrounding sediment. Wadley said:

Discoveries at Border Cave

This new discovery adds to the long list of important finds at Border Cave. The site has been repeatedly excavated since Raymond Dart first worked there in 1934. Among earlier discoveries were the burial of a baby with a Conus seashell 74,000 years ago, a variety of bone tools, an ancient counting device, ostrich eggshell beads, resin, and poison that may once have been used on hunting weapons.

Border Cave is a heritage site with a small site museum. The cave and museum are open to the public. (Image: Wits University)

The Border Cave Heritage Site

Wadley and her colleagues hope that the Border Cave discovery will emphasize the importance of the site as an irreplaceable cultural resource for South Africa and the rest of the world.

About Hypoxis angustifolia

Hypoxis angustifolia is evergreen, so it has visibility year-round, unlike the more common deciduous Hypoxis species. It thrives in a variety of modern habitats and is thus likely to have had wide distribution in the past as it does today. It occurs in sub-Saharan Africa, South Sudan, some Indian Ocean islands, and as far afield as Yemen.

Its presence in Yemen may imply an even wider distribution of this Hypoxis plant during previous humid conditions. Hypoxis angustifolia rhizomes grow in clumps, so many can be harvested at once. Wadley said:

Hunter-gatherers tend to be highly mobile so the wide distribution of a potential staple plant food would have ensured food security.

Provided by: Wits University [Note: Materials may be edited for content and length.]

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