How do we know when people developed minds capable of solving problems in the way that we do today? Archaeologists cannot excavate human minds from the past: they can only recover the material remains created by those minds. In the case of the people of Sibudu Cave in KwaZulu-Natal, we can see that some items that they made required special skills that could only have been undertaken with minds like ours.
Mixing substances, like tempera paint, is one example of behaviour that involves the sort of brain power that we associate with people today. Sibudu’s people made paint from powdered ochre and milk extracts from wild animals because the process took place 49,000 years before the arrival of cows.
It is clear that that this type of composite paint cannot be made from precise recipes because the attributes of natural ingredients, like absorbency, vary according to local conditions. An artist must decide on recipe quantities while assembling the paint mix, and may need to make changes swiftly to avoid spoiling the product.
The ability to do this implies long attention spans, a capacity for multi-tasking and the ability to plan the assembly of ingredients. Such behaviour, also inferred from the making of compound adhesives at Sibudu, implies complex cognition of the kind possessed by modern people.
Discovered by an international team of researchers, the unusual paint mixture used approximately 49,000 years ago at Sibudu Cave shows that milk was used as a binder well before the introduction of domestic cattle in South Africa in the first millennium AD.
The paint mixture contained red powdered ochre and casein, which is dried milk protein. Casein is an ingredient of tempera paint, though some recipes use egg.
The casein was clearly not human, nor equid, but it closely resembled bovid. Domestic cows are bovids, but cattle were not present in southern Africa 49,000 years ago. The earliest date for these is AD 420 from the site of Mzonjani, near Durban, where early farmers kept cattle.
Because the Sibudu paint predates cattle farming, it must have been made from the milk of a wild bovid. Bones of bovids that are known to have been the prey of the early hunters such as buffalo, eland, kudu, impala and duiker have been found at the site.
Sibudu is already well known for having the earliest evidence in the world (77,000 years ago) for plant bedding with insecticidal properties, as well as early engraving of bone and ochre, and the manufacture of marine shell beads.
The paint residue looks like cracked mud on the edge of a small stone flake excavated from the cave. A micro-sample (3.3 mg) of residue was removed from the flake for testing. The researchers used elemental analyses (scanning electron microscopy with energy-dispersive X-ray spectroscopy and chemical analyses (gas chromatography/mass spectrometry) to establish that powdered ochre was mixed with milk in its liquid form.
The elemental analysis identified hematite and clay minerals in the ochre powder. The chemical analysis identified several amino acids that were submitted to principal component analysis with more than 100 reference samples. The presence of casein was inferred from the score plot. The question that arose from this initial analysis was: what kind of milk was used? Was it human or animal?
Proteomic (protein) analyses were conducted on the casein and on a set of Sibudu bones from the same layer. The bones were from zebra and from various medium-sized bovids, for example, hartebeest and wildebeest.
Milk may have been obtained by killing a lactating or juvenile bovid. Many wild bovids separate from the herd when giving birth and some, like kudu, hide their young and go off to browse alone. Such animals are easy prey for hunters. Richard Klein concluded that hunters at Klasies River Cave I, southern Cape, targeted giant buffalo in advanced pregnancy or in the process of giving birth.
Such cows would already have milk. Many southern African bovids give birth in early summer, so the use of milk could have seasonal implications. Nevertheless, small bovids like duiker may give birth several times a year making the season of collection uncertain.
Older than Greek and Egyptian art works
Casein paint was used for art works about 3000 years ago in Greece and Egypt, but the Sibudu find is much older. The Sibudu liquid paint may have been used as body decoration or for painting on surfaces such as stone or wood.
Body painting is documented in San ethnographies and in rock art images. Ian Watts claims that red ochre was used as body paint for rituals from about 100 000 years ago. There are, however, no ethnographic precedents for mixing ochre with milk as a body paint, though modern Himba in Namibia mix ochre with butter as a coloring agent for skin, hair and leather clothing.
Ochre traces inside perforated marine shells from Blombos Cave, Sibudu, Border Cave and North African sites suggest to Marian Vanhaerenand Francesco d’Errico that they may have been worn against painted bodies. An ochre-rich compound blended with marrow fat was found stored in two abalone shells at the site of Blombos (100,000 years ago).
Christopher Henshilwood and colleagues propose that this product may have been for decoration, but could have been for skin protection. Riaan Rifkin has shown that ochre can be both an effective sun screen and an insect repellent.
While it is not impossible that Sibudu’s tempera paint was used for body painting, the medium has a tendency to crack on flexible surfaces and is better suited to rigid planes like stone or wood. Rock paintings are known in Europe from about 40,000 years ago, but the earliest known southern African figurative art is dated to approximately 27,000 years ago at Apollo 11, Namibia.
These plaques have not yet been chemically analysed so we do not know how the paint was made. Where chemical studies have been conducted, neither milk nor casein has been documented as media for southern African rock art.
The why and the how
Although the use of Sibudu’s tempera paint remains uncertain, the people who made the product may have attributed a special significance and value to it. Whether or not it was obtained in a specific season, the bovid milk would have been an irregular acquisition.
Milk spoils quickly. So, in the absence of refrigeration, tempera paint must be used soon after manufacture. Although speculative, it is tempting to suggest that Sibudu’s tempera was reserved for special tasks that were different from ones making use of other ochre recipes.
Francesco d’Errico has suggested that the production of figurative art may not have a single geographical or cultural origin. The use of tempera paint at Sibudu suggests, further, that there may once have been several cultural traditions involved in the manufacture of colouring agents, just as there were distinct traditions involved in making bone and stone tools.