Tanzania’s archaeological sites at Olduvai Gorge and Laetoli make the Ngorongoro Conservation Area one of the world’s most significant places for the study of human evolution. Visit this cradle of mankind and the nearby Shifting Sands for a journey into the very origins of our species.
My partner and I left our lodge at Ngorongoro Crater early one morning and were driven northwest towards the Serengeti through a beautiful, elemental landscape. We were thrilled to be heading for the internationally-renowned archaeological sites of Laetoli and Olduvai Gorge. Both places continue to contribute significantly to our understanding of humankind’s physical, behavioural and technological evolution.
We reached Olduvai and climbed out. Before us was a steep-sided ravine in the Great Rift Valley. Olduvai Gorge is about 48km long and located in the eastern Serengeti Plain. At the top stood a small museum. We stepped inside and found fascinating exhibits, including fossils and artefacts belonging to our human ancestors, as well as skeletons of many extinct animals that shared their world.
Then we were joined by a guide, Moses, who led us around the site. We stood looking down into the gorge. ‘Some 30,000 years ago, a splitting of the earth’s surface by violent geological activity and millennia of erosion by seasonally flowing streams incised this 90m-deep canyon,’ said Moses. ‘Natural forces exposed a remarkably rich geological chronicle of human ancestry. Over the last half century, it’s become increasingly apparent that Africa is the “Cradle of Humankind”. From Africa, our ancestors spread out to populate the rest of the earth. Remains of the earliest humans were found right here in Oldupai Gorge.’
‘But Moses, on my map it says Olduvai,’ I interrupted.
‘That’s the old name. Olduvai is a misspelling of Oldupai, a Maasai word for the wild sisal plant that grows here.’
As we walked through the site, Moses talked about how Oldupai has proven invaluable in furthering our understanding of human evolution. He spoke about the pioneering work of the British-Tanzanian paleoanthropologist team of Mary and Louis Leakey. This intrepid couple established and developed the excavation and research programmes at Olduvai Gorge. The Leaky excavations yielded four different kinds of hominid, showing a gradual increase in brain size and in the complexity of their stone tools.
‘Homo habilis was probably the first early human species and occupied Oldupai about 1,9 million years ago,’ explained Moses. ‘Homo habilis was followed by a contemporary australopithecine, Paranthropus boisei, 1,8 million years ago. Then came Homo erectus, 1,2 million years ago. And finally, of course, there was us: Homo sapiens. We occupied the site a mere 17,000 years ago.
‘Oldupai is so significant because it shows us the increasing developmental and social complexities in the earliest humans, largely as revealed in the production and use of stone tools. And prior to tools, the evidence of scavenging and hunting – demonstrated by gnaw marks that predate cut marks – and of the ratio of meat versus plant material in early hominin diet.
‘The collection of animal remains and tools in a central area is evidence of developing social interaction and communal activity. All these factors indicate an increase in mental capacity.’
After a few captivating hours, we climbed back in the 4×4 and drove to Laetoli. Here Moses showed us how hominid footprints had been preserved in 3,6-million-year-old volcanic rock. These represent some of the earliest signs of humankind in the world.
‘Made by feet that were little different to our own, the footprints proved conclusively that these creatures stood and walked upright with a human-like stride a million years before the invention of stone tools,’ said Moses. ‘It’s one of the most important scientific discoveries of our time.
‘Three separate tracks of a small-brained, upright-walking early hominid were uncovered. Australopithecus afarensis was a creature of about 1,2m to 1,4m high … and was found right here! The expanse of time separating that creature from us is simply mind boggling.’
Before heading back to camp, we made a short detour to view the famous Shifting Sands. This remarkable black dune, composed of volcanic ash from Ol Doinyo Lengai Mountain, are being blown slowly westwards across the plains at the rate of approximately 17m per year. The main dune is about 9m high and 100m along its curve.
Such crescent-shaped dunes are a rare phenomenon and are technically referred to as barchan. They’re formed when there’s ample dust on the ground and a unidirectional wind. The volcanic ash (or dust) collects around a rock or other object, and builds continually until it forms a small dune.
‘The local Maasai believed that these sand dunes originated from Ol Doinyo Lengai – “the mountain of god” and the holiest place in their culture,’ said Moses.
The sand is extremely magnetic due to its high levels of iron. I scooped up a handful and tossed it into the air. Rather than being dispersed and blown away, the grains clumped together and fell back to earth in a dense black cloud. It was a most startling conclusion to a most remarkable day exploring Africa’s ancient past … and the very origins of our species.