The Cradle of Mankind

Olduvai Gorge or Oldupai Gorge is commonly referred to as "The Cradle of Mankind” and is one of the most important prehistoric sites in the world. Instrumental in furthering understanding of early human evolution, its excavation was pioneered by Louis and Mary Leakey in the 1950s. A steep-sided ravine in the Great Rift Valley, the gorge is about 50km long and up to 90m deep; it runs to the north-west of the Ngorongoro Crater. Thanks to its unique geological history, in which layer upon layer of volcanic deposits were laid down in orderly sequence over a period of almost 2 million years, the site provides remarkable documentation of ancient life. The gorge is named after the Maasai word for the wild sisal plant Sansevieria ehrenbergii, commonly called Oldupaai.

Olduvai’s treasures

The most famous of Olduvai’s fossils is the 1.8 million-year-old ape-like skull known as Australopithecus boisei, which was discovered by Mary Leakey in 1959.The skull is also often referred to as zinjanthropus, which means ‘nutcracker man’ referring to its large molars. In 1972 hominid (human-like) footprints estimated to be 3.7 million years old were discovered at Laetoli, about 45km south of Olduvai Gorge. Based on these findings as well as other ancient fossils excavated in Kenya and Ethiopia, experts believe that there were at least three hundred hominid species living in this region about two million years ago, including Australopithecus boisei, Homo habilis and Homo erectus. While Australopithecus boisei and Homo habilis appear to have died out, it is thought that Homo erectus continued and evolved into Homo sapiens or modern man. There is a small and interesting museum just off the road to Serengeti (open until 3pm). 

Geology and paleontology

Around 500,000 years ago seismic activity diverted a nearby stream which began to cut down into the sediments, revealing seven main layers in the walls of the gorge. The geology of Olduvai Gorge and the surrounding region was studied in detail by Richard L. Hay, who worked at the site between 1961 and 2002. The stratigraphy is extremely deep; layers of volcanic ash and stones allowing radiometric dating of the embedded artifacts, (mostly by means of potassium-argon and Argon–argon dating..

FLKN and Bed 1 and Bed II

The earliest archaeological deposit, known as Bed I, has produced evidence of campsites and living floors along with stone tools made of flakes from local basalt and quartz. Since this is the site where these kinds of tools were first discovered, these tools are called Oldowan. It is now thought that the Oldowan tool making tradition started about 2.6 million years ago. Bones from this layer are not of modern humans but primitive hominid forms of Paranthropus boisei and the first discovered specimens of Homo habilis. The site of Frida Leakey Korongo North (commonly known as FLK North and named after Louis Leakey's first wife) bears the distinction of having the oldest known evidence of elephant consumption, attributed to Homo ergaster around 1.8 million years ago. A nearly complete skeleton of the extinct Elephas recki was found in the lowest of its six occupation levels along with stone tools such as choppers and flakes. Large numbers of bone fragments of smaller animals found with it clearly identify FLK North as an early butchering site. Above this site, in the area known as Bed II, research reveals that the earlier pebble tools began to be replaced by more sophisticated Acheulean hand axes, thought to have been made by Homo ergaster. Although this layer has not yet been successfully dated, it is thought that it dates back to  between 1.75 and 1.2 million years ago. Beds III and IV have produced Acheulean tools and fossil bones dating back to 600,000 years ago.