Beyond the Shadow of a Desert: Aquatic Resource Intensification on the Roof of Southern Africa

1. What they did

Much of what archaeologists think about Africa’s ancient hunter-gatherers comes from studies of living groups in warm, dry places such as the Kalahari Desert. The authors argue that this picture is too narrow, because Africa’s past climates were often much colder than today. Studies of hunter-gatherers worldwide (by Lewis Binford) suggest that people living in cold places cannot rely mainly on plants and tend to turn to fish and other water foods.

To test this, they looked at one of southern Africa’s coldest regions, the Maloti-Drakensberg Mountains of Lesotho, “the roof of southern Africa”. They:

• Pulled together the climate record for the region over about the last 25,000 years, from plant remains, soils, glacial landforms and dated layers.
• Compared fish bones and mammal bones layer by layer at three archaeological sites close together on the Orange-Senqu River system: Sehonghong, Pitsaneng and Likoaeng. Together these hold one of the largest collections of freshwater fish remains in Africa south of the Sahara.
• Asked whether people fished more in cold periods, which fish they caught and in which season, and what this means for how people moved, made tools and stored food.

2. What they found

Climate

• There were at least three sharply cold periods: about 24,000 to 18,000 years ago (the Last Glacial Maximum, LGM), about 14,800 to 13,700 years ago (the Antarctic Cold Reversal, ACR), and about 3,500 to 2,000 years ago (the Neoglacial).
• In these periods, cold alpine grasses, which are poor food for grazing animals, spread hundreds of metres down the slopes into the river valleys. At Likoaeng the Neoglacial drop was at least 400 m, with temperatures at least 2.5°C lower than today.

Fishing and cold

• Fishing peaked at Sehonghong about 25,000 to 24,000 years ago (start of the LGM) and about 14,900 to 12,600 years ago (the ACR), and at Likoaeng about 3,000 to 1,750 years ago (the Neoglacial). In warmer periods people ate relatively little fish.
• At Likoaeng, fish bones massively outnumber mammal bones from about 3,000 years ago, and hunting of large hoofed animals dropped sharply at the start of the Neoglacial.
• One exception: after the Neoglacial, fishing stayed high at Likoaeng into the first millennium AD, and Sehonghong’s richest fish layer also dates to this time.

Which fish, and when

• The smallmouth yellowfish made up at least 80% of fish at Sehonghong in every layer, which suggests the site was used mainly in summer.
• At Likoaeng the Orange River mudfish dominates most layers. The mudfish spawns in the rapids next to the site from spring to midsummer, mainly in November, so people probably camped there to catch the spawning runs. Mudfish build up fat before breeding, which would have made them valuable in spring, when game animals are thin and few plant foods are ready.
• During the coldest Neoglacial layers the smallmouth yellowfish, which tolerates colder water and spawns later (peak in January), took over, so people probably camped there later in summer.
• The Neoglacial layers also hold the most small and immature fish, which may point to non-selective mass capture with baskets, fences and drag screens. Fishing and fish traps appear in the region’s rock art, including a panel next to Likoaeng.

Who left the bones

The authors are confident people, not animals, collected the fish: many bones are burnt, none show gnawing or digestion, and they lie with charcoal and stone tools. Otters, the only regular fish-eaters among the animals found, usually eat in the water and leave droppings at the water’s edge, and the crabs that make up much of their diet are almost absent.

Storage and movement

• There is no sign that fish were dried or smoked for storage at Likoaeng; the large catches more likely fed spring and summer gatherings.
• In cold periods people seem to have crowded into the deep river valleys, with higher ground visited less often.
• The earliest known Robberg bladelet tools in southern Africa appear at Sehonghong just before the LGM.

3. What they concluded

• Highland hunter-gatherers turned to river fish when cold periods made game and plant foods harder to find, as Binford’s worldwide studies predict.
• Cold periods probably pushed people into the river valleys, and may have encouraged mass-capture fishing and more reliable multi-part hunting tools.
• People did not appear to store fish. They may have avoided needing to by spending winters at lower, warmer altitudes in KwaZulu-Natal or the Eastern Cape, but seasonal movement in the region is still poorly understood.
• Ancient hunter-gatherers in southern Africa did things with no parallel in Kalahari ethnography. Archaeologists should test the record against wider theory about hunter-gatherers rather than relying on Kalahari groups as the model.

7. Implications for conservation (from the paper)

• Fish were probably far more plentiful in highland Lesotho before soil erosion, overgrazing and invasive trout. Archaeological fish were larger than any recorded recently in highland Lesotho and larger than the southern African angling records.