Safari, Part Four: Oldupai Gorge

Between Serengeti and Ngorongoro, there’s a small road off into the bush that leads to a remarkable place, which I was very excited to visit. In college I was an anthropology major and we reverentially learned about the stone tools and fossil hominids that Mary and Louis Leakey found in Olduvai Gorge. It’s still an active archeological site, but they have also built a visitor’s center with a small museum and an overlook to the gorge so you can see some of the strata for ourselves. They call it Oldupai “George” and we enjoyed a short talk by one of the guides, took some photos, and were back on the road in about an hour.

The small Australopithecus skeleton known as “Lucy,” discovered in the early 1970s, was found in Ethiopia, actually. So what makes Oldupai unique as a site for hominid and extinct mammal species is two things: 1) five distinct intact strata of geological layers that go back 2 million years in well-preserved vertical order (which means you can establish relational time among the fossils and determine which are older, and can date them using argon dating), and 2) the Laetoli ash field, in which there are well-preserved hominid footprints dated to 3.6 million years ago. The ash field has now been conserved (tree roots removed and such) and reburied to preserve it, but there are good plaster casts of it, like this one on display at Oldupai in the museum.



The oldest layer (#1) contained rough stone tools and fossil fragments from two coexistent species of hominids, Australopithecus “Zanj” (discovered in 1959 by Mary Leakey) and Homo Habilus (found in 1960) – both around 1.75 million years ago. The next oldest layer (#2, a thick ash layer from when the Ngorongoro volcanoes were erupting), contained fossils of Homo Erectus. Then the region dried up and there are few fossils, and Homo Erectus apparently starting going somewhere else, migrating to become Peking Man in China, Neanderthal Man in Europe, etc. The upper layers at Oldupai contain fossils of Homo Sapiens, and H. Sapiens Sapiens.

Here’s a view down into the gorge (a gorge, by the way, is like a canyon in that its sides are steep and it was carved by water, but it’s shallower than a canyon), showing a eroded spike that has the first 3 layers of the 5 strata. The two top layers have been weathered away on this spike, but are present elsewhere in the gorge.



It’s more than just a rich repository of hominid evidence, though – we saw plaster casts of ginormous extinct animals, tools and flakes, and other finds. For an anthropology junkie like me, it was totally amazing to be there in person and see it for myself!