Olduvai Gorge - Home of Ancient Humans in Tanzania, Africa

Where Is Olduvai Gorge, and What--or Who--Did the Leakeys Find There?

Olduvai Gorge, Tanzania
Olduvai Gorge, Tanzania. *SHERWOOD*

Olduvai Gorge is a 20 kilometer (12.4 mile) long east-west trending narrow valley in the eastern Rift Valley of northern Tanzania. The gorge cuts deep into approximately 140 meters (460 feet) of ancient Pleistocene through Holocene dated sedimentary and volcanic rocks. It was at Olduvai that paleoanthropologists Louis and Mary Leakey discovered the first recognized ancient human (or hominin) fossils in East Africa, ushering in a "golden age of paleoanthropology".

The Leakeys identified two major hominin occupation sites in Olduvai, called FLK and FLK NN, located close together on the margin of an ancient extinct lake called Paleo-Lake Olduvai. There the Leakeys identified the species Zinjanthropus (now called Paranthropus boisei) (now known to have existed between 2.3-1.2 million years ago [mya]). They also detected the first archaeological sequence in East Africa where stratigraphic transition from the Oldowan (Homo habilis 2.4 to 1.4 mya) to the Acheulean (H. erectus, 1.9 million-145,000 ya) can be seen.


Geological analysis of Olduvai's ~140 meter thick stratigraphy was made by geologist Hans Reck in 1913; connected to the hominid discoveries by the Leakeys in the 1930s; and fully described by Richard L. Hay in his seminal 1976 book, Geology of the Olduvai Gorge. While considerable discussion of the interpretation of the different stone tools found in the different layers and how they should be classified has occurred over the past fifty years, the stratigraphic analysis has remained fairly stable.

  • Naisiusu Beds: 62,000-42,000 years before the present (bp)
  • Ndutu Beds: Middle Stone Age (Levallois) ~450,000-210,000 bp
  • Masek Beds: 780,000-500,000 bp
  • Bed IV: early Acheulean, cleavers, bolas, bifaces, 950,000-780,000 bp
  • Bed III: transitional Chellean to Acheulean, first appearance of cleavers, 1.2 m-950,000 bp
  • Bed II: early Chellean tools and advanced Chellean, first crude handaxes, 1.785-1.15 mya
  • Bed I: Oldowan tradition, archaic stone tools, no handaxes, ~2-1.785 mya
  • Naabi Ignimbrite, >2 mya (no human fossils)


In 1959-1960, the Leakeys recognized two localities at Olduvai in Bed I that contained the remains of ancient hominids: FLK and FLK NN. The evidence from these two sites was the first ever of the co-existence of two ancient hominin genera: P. boisei and H. habilis.

FLK Site. FLK Level 22 had a desne assemblage of stone artifacts (2566) and mammal fossils (3510), representing an ecologically diverse set of animals, including four hominin individuals OH5, 6, 35 and 44.

  • OH5: cranium of Paranthropus boisei adolescent, probably male, about 15-17 years old
  • OH 6: three teeth and six calvaria fragments from a 5-6 year old Homo habilis child
  • OH 35: tibia and fibula of an adult H. habilis or possibly P. boisei
  • OH44: tooth from a H. habilis child 4-5 years old

FLK has been interpreted as lots of things over the decades since its discovery, but most typically it is considered a "home base" where Homo and Paranthropus hunter-gatherers lived for several consecutive days and nights. Evidence for stone tool cut marks on the animal bone was identified at FLK 22 by Henry Bunn, and later scholars have debated this ever since.

The occurrence of cut marks is still somewhat in debate--and if it stone tool use in the manner did occur it was pretty rare. Scholars do agree there is ample evidence of deliberate percussion, that is, the use of hammerstones to crack open long bones to retrieve marrow.

FLK NN Site. Located 200 m north of FLK, FLK NN contained two Oldowan assemblages: the younger one, Level 1, contained scattered stone artifacts (34) and sparse vertebrate fauna (275). Level 3 included more abundant stone artifacts (75) and animal fossils (2,158, including OH7 and OH8, both skeletal fragments of H. habilis.

Archaeological Research in the Olduvai Gorge

German geologist Hans Reck visited the Olduvai Gorge in the first decade of the 20th century and established the geological sequence still used today, but he found no stone tools indicating the presence of humans in OG--De la Torre and colleagues believe he was convinced he wouldn't find anything.

It was Louis Leakey who discovered handaxes on the very first day of his first expedition in 1931--but then, Leakey was convinced he would find them.

The Olduvai Landscape Paleoanthropology Project (OLAPP), began in 1989, and has conducted 16 field seasons between then and 2008. In 2012, the OLAPP published a complete issue focused on Beds I and II in the Journal of Human Evolution. In 2006, the Olduvai Paleoanthropology and Paleoecology Project (TOPPP) began work in the Gorge.


This article is a part of the About.com guide to the Lower Paleolithic, and the Dictionary of Archaeology.

Blumenschine RJ, Stanistreet IG, and Masao FT. 2012. Olduvai Gorge and the Olduvai Landscape Paleoanthropology Project. Journal of Human Evolution 63(2):247-250.

Blumenschine RJ, Stanistreet IG, Njau JK, Bamford MK, Masao FT, Albert RM, Stollhofen H, Andrews P, Prassack KA, McHenry LJ et al. 2012. Environments and hominin activities across the FLK Peninsula during Zinjanthropus times (1.84 Ma), Olduvai Gorge, Tanzania. Journal of Human Evolution 63(2):364-383.

Bunn HT, Kroll EM, Ambrose SH, Behrensmeyer AK, Binford LR, Blumenschine RJ, Klein RG, McHenry HM, O'Brien CJ, and Wymer JJ. 1986. Systematic Butchery by Plio/Pleistocene Hominids at Olduvai Gorge, Tanzania [and Comments and Reply]. Current Anthropology 27(5):431-452.

de la Torre I, and Mora R. 2014. The Transition to the Acheulean in East Africa: an Assessment of Paradigms and Evidence from Olduvai Gorge (Tanzania). Journal of Archaeological Method and Theory 21(4):781-823.

Deino AL. 2012. 40Ar/39Ar dating of Bed I, Olduvai Gorge, Tanzania, and the chronology of early Pleistocene climate change. Journal of Human Evolution 63(2):251-273.

Diez-Martín F, Sánchez P, Domínguez-Rodrigo M, Mabulla A, and Barba R. 2009. Were Olduvai Hominins making butchering tools or battering tools? Analysis of a recently excavated lithic assemblage from BK (Bed II, Olduvai Gorge, Tanzania). Journal of Anthropological Archaeology 28(3):274-289.

Eren MI, Durant AJ, Prendergast M, and Mabulla AZP. 2014. Middle Stone Age archaeology at Olduvai Gorge, Tanzania. Quaternary International 322–323:292-313.

Hay RL. 1976. Geology of the Olduvai Gorge: A Study of Sedimentation in a Semiarid Basin. Berkeley: University of California Press.

McHenry LJ. 2012. A revised stratigraphic framework for Olduvai Gorge Bed I based on tuff geochemistry. Journal of Human Evolution 63(2):284-299.

Pante MC, Blumenschine RJ, Capaldo SD, and Scott RS. 2012. Validation of bone surface modification models for inferring fossil hominin and carnivore feeding interactions, with reapplication to FLK 22, Olduvai Gorge, Tanzania. Journal of Human Evolution 63(2):395-407.

Stanistreet IG. 2012. Fine resolution of early hominin time, Beds I and II, Olduvai Gorge, Tanzania. Journal of Human Evolution 63(2):300-308.

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Hirst, K. Kris. "Olduvai Gorge - Home of Ancient Humans in Tanzania, Africa." ThoughtCo, Nov. 20, 2015, thoughtco.com/olduvai-gorge-home-of-ancient-humans-172004. Hirst, K. Kris. (2015, November 20). Olduvai Gorge - Home of Ancient Humans in Tanzania, Africa. Retrieved from https://www.thoughtco.com/olduvai-gorge-home-of-ancient-humans-172004 Hirst, K. Kris. "Olduvai Gorge - Home of Ancient Humans in Tanzania, Africa." ThoughtCo. https://www.thoughtco.com/olduvai-gorge-home-of-ancient-humans-172004 (accessed December 13, 2017).