Earliest ‘Cavemen’ Discovered in South Africa

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Evidence of the Earliest ‘Cavemen’ Discovered in South Africa
Dr James Beresford
March 26, 2009

Archaeologists excavating Wonderwerk Cave, located in the Asbestos Hills of South Africa’s Northern Cape Province, have recently discovered evidence of early hominid activity from 2 million years ago, a date that provides the first evidence of human ancestors occupying caves: in effect the site at Wonderwerk bears witness to the emergence of the first ‘cavemen’.

The large cave at Wonderwerk, which measures 130m in length, has long been of scientific interest and contains wall paintings which date back 10,000 years. However, much of the archaeology of the cavern was destroyed during the Second World War when the bat guano lining the floor of the cave was commercially mined for use as agricultural fertilizer. However, while these mining operations were taking place, a series of brief archaeological excavations were carried out between 1940-48. A number of excavations have continued at the site since the early 1970s, while the most recent archaeological investigations, carried out under the direction of Michael Chazan (University of Toronto) and Liora Kolska Horwitz (Hebrew University, Jerusalem), in collaboration with the McGregor Museum, have focused their efforts on the lower levels of sediment near the front of the large cavern. A number of small stone tools have been recovered from excavations of this level, while the geology of the cave indicated that they were deposited there by early humans and were unlikely to have been washed into the cave from outside; clear evidence in support of the theory that early tool-making hominids were occupying the cave.

In an effort to determine the earliest period of hominid activity soil samples were taken from the lowest level of occupation in the cave before being subjected to dating analysis. Unfortunately, while the early hominid sites in East Africa can usually be dated using the layers of volcanic ash common in this region by the Potassium-argon dating method, ash layers are lacking in southern areas of Africa. However, the excavators subjected the soil samples recovered from the cave to two methods of dating that securely place the earliest hominid activity at the Wonderwerk site to about 2 million years ago. Hagai Ron (Hebrew University, Jerusalem) studied the palaeomagnetism of the samples to determine changes in the directions and intensities of the magnetic field in the soil sequences.

 After plotting them against those known from global timescales, was able to generate a date for the lowest levels of the cave. Ari Matmon (Hebrew University, Jerusalem) also applied Cosmogenic Burial Age Dating, carefully preparing the soil samples in the laboratory before sending them to an atomic accelerator in the United States where the relative decay of cosmogenic nuclides Beryllium-10 and Aluminum-26 was measured (a procedure that, though similar to the carbon-14 dating method, provides dates that are considerably older). This also confirmed that the sediment had been laid down around 2 million years ago. Although the stone tools found in the cave are therefore considerably younger than those discovered at the site of Gona, Ethiopia, which were fashioned about 2.6 million years ago, the discoveries from Wonderwerk are of similar age to those recovered from the bottom levels at Olduvai Gorge, Tanzania.

Unfortunately no hominid remains have been recovered from the Wonderwerk cave, and, because there were a number of different hominid species co-existing in southern Africa at this time, attributing the stone tools to one particular type of human ancestor is problematic. However, the most likely candidate as the manufacturer of the stones is Homo habilis, perhaps the earliest tool-making hominid whose name fittingly translates to ‘handy man’. Remains of hominids discovered at sites in the Olduvai Gorge in Tanzania, and at Lake Turkana, Kenya, suggest Homo habilis was about 1.3m in height, and possessed a cranial capacity of about 600-650cm³, giving the hominid a brain only half the size of that of a modern human, but which was almost twice as large as that of the australopithecines from which Homo habilis may have evolved.