September 25 2002
By Lucille Davie
A HANDFUL of the world's great cities trace their heritage to early human settlements thousands of years back. Johannesburg's earliest residents were in the neighbourhood three million years ago.
Fifty kilometres west of the city, among nondescript koppies, scattered shrubs and trees, is a 47 000 hectare valley known as the Cradle of Humankind. Three million years of human activity have taken place in and around these caves, including man's earliest-known mastery of fire, and forty percent of all the world's human ancestor fossils have been found here.
You can discover the area yourself, by taking your own custom-made tour of the area. The Palaeo-Anthropology Scientific Trust conducts tours conducted by University of the Witwatersrand post-graduate palaeontology students. And you can design your own tour to suit your interests.
The biggest and best-known of the caves is Sterkfontein, where over 500 hominid fossils and over 9 000 stone tools have been found. It was at Sterkfontein that two major finds were made, that have changed modern paleontology:
- The Australopithecus africanus Mrs Ples (now believed to be a Mister Ples), dating back 2.5-million years, and found by Robert Broom in 1947.
- Little Foot, an almost complete ape-man skeleton 3.3-million years old, found by Ronald Clarke and Phillip Tobias in 1995 (the bones had lain in a box since the late 1970s, when they were excavated).
Professor Philip Tobias gives a lecture to VIP visitors to the Sterkfontein Caves during the World Summit (left to right): SA Deputy President Jacob Zuma, world-renowned primatologist Jane Goodall, Mrs Annan, UN Secretary-General Kofi Annan, and President Thabo Mbeki.
(Photo: United Nations)
Some believe that Little Foot is the most significant hominid find since Raymond Dart's discovery of the skull of the Taung child, a juvenile Australopithecus africanus, discovered in 1924 near a town called Taung in the far north of the North West Province.
Sterkfontein also made world headlines in December 1998 when Clarke found an almost complete hominid skeleton in the cave, dating back 3.5-million years. A complete skull and fragments of arm, foot and leg bones have been uncovered so far; the rest of the bones are still being painstakingly dug from the rock.
The Sterkfontein valley consists of around 40 different fossil sites, 13 of which have been excavated. It includes Bolt's Farm, where the remains of three sabre-tooth cats have been found in a pit that trapped animals; Swartkrans, site of the earliest-known deliberate use of fire, around 1.3-million years ago; Haasgat, where the fossils of early forest-dwelling monkeys, around 1.3-million years old, were found; and Gondolin, where 90 000 fossil specimens have been found since 1979.
The area was declared a World Heritage Site in 1999. Although it is on privately owned land, any finds belong to the world, and the area is strictly controlled and protected. South Africa has two other heritage sites: Robben Island (where Nelson Mandela spent many years), and Lake St Lucia in KwaZulu-Natal (with five separate ecosystems).
Beginnings
In the late 1890s, miners dynamited the Sterkfontein caves, searching for limestone which they converted into quick lime, an element needed for the processing of gold and the manufacture of cement. They displaced the sediment and revealed entrances to the caves.
The rocks contain cyclindrical shapes - evidence of early life called stromatolite, dating back 3.8-billion years. These organisms breathed in carbon dioxide and breathed out oxygen, thus increasing the earth's oxygen levels and leading to the evolution of other forms of life.
Some 2.5-billion years ago, the area was an inland shallow sea. Over time the water evaporated and the mud formed dolomite rock, in which the stromatolite are visible. Around 2-billion years ago a large meteorite, 10 kilometres in diameter, fell in Vredefort (100 kilometres south of Sterkfontein), leaving a massive crater now known as the Vredefort Dome. The entire area for hundreds of kilometres around was covered in debris, which helped preserve the gold reefs of the Witwatersrand, preventing them from being eroded - and also helped preserve the stromatolite rocks.
Some 3.5-million years ago, openings to the caves started appearing. They may have been occupied by sabre-toothed cats and other predators which would explain why the remains of large herbivores like wildebeest, extinct zebra and buffalo have been found in the caves.
One of the caves is called Plover's Lake Cave. It has been explored some 50 metres down, but beyond that point are a labyrinth of unexplored passages, and several entrances. A hyena and a porcupine are known to live there - no-one has spotted them, but their footprints are often seen. Excavations of Plover's Lake Cave and others in the area is ongoing.
The nearby Wonder Cave has an enormous chamber with beautiful 15 metre-high stalactite formations. The Cave is believed to be 2.2-million years old, and bones of rodents, frogs, lizards and birds have been found in the cave.
It's hard while walking around the area to fully comprehend the age of the sites and the importance of the finds. Charles Darwin predicted in the 19th Century that the origins of humankind would be traced back to Africa because that's where the great apes live. South Africans, and Jo'burgers in particular, don't have far to go to take a stroll into life millions of years ago . . . so long as they are mindful of hyenas and porcupines.
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