Richard G. Klein researches the archeological and fossil evidence for the evolution of human behavior. He has done fieldwork in Spain and especially in South Africa, where he has excavated ancient sites and analyzed the excavated materials since 1969. He has focused on the behavioral changes that allowed anatomically modern Africans to spread to Eurasia about 50,000 years ago, where they swamped or replaced the Neanderthals and other non-modern Eurasians.
After earning his undergraduate degree from the University of Michigan, Mr. Klein went to the University of Chicago to pursue his M.A. and Ph.D. degrees. Following receipt of his doctorate, he taught at the University of Wisconsin-Milwaukee, Northwestern University, the University of Washington, and for 20 years at the University of Chicago. He came to Stanford from Chicago in 1993.
Mr. Klein has served on numerous editorial and advisory boards, he has edited The Journal of Archaeological Science since 1981, and he co-chairs the Grants Committee of the L.S.B. Leakey Foundation. He is a member of the American Academy of Arts and Sciences and of the National Academy of Sciences.

Academic Appointments

  • Professor, Anthropology
  • Professor, Biology

Boards, Advisory Committees, Professional Organizations

  • Co-Chair, Leakey Foundation Science and Grants Committee (1995 - Present)
  • Member, American Association of Physical Anthropologists (1966 - Present)
  • Editor, Journal of Archaeological Science (1981 - Present)
  • Member, National Academy of Sciences (2003 - Present)
  • Fellow, American Academy of Arts and Sciences (1992 - Present)

Professional Education

  • Ph. D., University of Chicago, Anthropology (1966)
  • M. A., University of Chicago, Anthropology (1964)
  • B. A., University of Michgain, Anthropology (1962)

Current Research and Scholarly Interests

My primary interest is in the co-evolution of anatomy and behavior in human evolution. My research is mainly on ancient animal remains as indicators of early human ability to make a living. I have analyzed more than 100 assemblages of animal fossils, primarily from southern African archaeological sites dating between 700,000 years ago and the historic present. I am currently directing excavations at a site 70 km NNW of Cape Town that dates from the Last Interglacial interval, between roughly 115,000 and 70,000 years ago. The animal remains show that the inhabitants exploited coastal resources much less efficiently than people who occupied the same coast during Present Interglacial (Holocene). The change in foraging efficiency probably occurred about 50,000 years ago and it helps explain the simultaneous expansion of anatomically modern humans from Africa to Eurasia, where they replaced the Neanderthals and other non-modern Eurasians.


  • Modern Human Origins, Stanford University and the Iziko Museum of South Africa

    Investigation of the archaeological and human fossil evidence for modern human origins. Field and laboratory work in South Africa.


    South Africa

    For More Information:

2023-24 Courses

Graduate and Fellowship Programs

  • Biology (School of Humanities and Sciences) (Phd Program)

All Publications

  • Profile of Svante Pääbo: 2022 Nobel laureate in physiologyor medicine. Proceedings of the National Academy of Sciences of the United States of America Klein, R. G. 2023; 120 (1): e2217025119

    View details for DOI 10.1073/pnas.2217025119

    View details for PubMedID 36580591

  • Mammoths and Neanderthals in the Thames Valley: Excavations at Stanton Harcourt, Oxfordshire (Book Review) JOURNAL OF ANTHROPOLOGICAL RESEARCH Book Review Authored by: Klein, R. G. 2022; 78 (2): 223-224

    View details for DOI 10.1086/719313

    View details for Web of Science ID 000842067800005

  • Middle Stone Age marine resource exploitation at Ysterfontein 1 rockshelter, South Africa. Proceedings of the National Academy of Sciences of the United States of America Klein, R. G. 2021; 118 (31)

    View details for DOI 10.1073/pnas.2107978118

    View details for PubMedID 34285083

  • A fossil history of southern African land mammals (Book Review) SOUTH AFRICAN JOURNAL OF SCIENCE Book Review Authored by: Klein, R. G. 2020; 116 (1-2)
  • Population structure and the evolution of Homo sapiens in Africa. Evolutionary anthropology Klein, R. G. 2019


    It has been proposed that a multiregional model could describe how Homo sapiens evolved in Africa beginning 300,000years ago. Multiregionalism would require enduring morphological or behavioral differences among African regions and morphological or behavioral continuity within each. African fossils, archeology, and genetics do not comply with either requirement and are unlikely to, because climatic change periodically disrupted continuity and reshuffled populations. As an alternative to multiregionalism, I suggest that reshuffling produced novel gene constellations, including one in which the additive or cumulative effect of newly associated genes enhanced cognitive or communicative potential. Eventual fixation of such a constellation in the lineage leading to modern H. sapiens would explain the abrupt appearance of the African Later Stone Age 50-45 thousand years ago, its nearly simultaneous expansion to Eurasia in the form of the Upper Paleolithic, and the ability of fully modern Upper Paleolithic people to swamp or replace non-modern Eurasians.

    View details for DOI 10.1002/evan.21788

    View details for PubMedID 31237750

  • Who We Are and How We Got Here: Ancient DNA and the New Science of the Human Past (Book Review) CURRENT ANTHROPOLOGY Book Review Authored by: Linderholm, A., Horsburgh, K., Vander Linden, M., Klein, R. G., Bandelt, H., Kirch, P. V. 2018; 59 (5): 655–62

    View details for DOI 10.1086/699987

    View details for Web of Science ID 000446120500009

  • Arrival routes of first Americans uncertain Response SCIENCE Braje, T. J., Rick, T. C., Dillehay, T. D., Erlandson, J. M., Klein, R. G. 2018; 359 (6381): 1225

    View details for PubMedID 29590068

  • Finding the first Americans. Science (New York, N.Y.) Braje, T. J., Dillehay, T. D., Erlandson, J. M., Klein, R. G., Rick, T. C. 2017; 358 (6363): 592-594

    View details for DOI 10.1126/science.aao5473

    View details for PubMedID 29097536

  • Francis H. Brown (1943-2017) IN MEMORIAM EVOLUTIONARY ANTHROPOLOGY Cerling, T. E., Klein, R. 2017; 26 (6): 245–48

    View details for PubMedID 29265658

  • Counting and miscounting sheep: genetic evidence for pervasive misclassification of wild fauna as domestic stock SOUTHERN AFRICAN HUMANITIES Horsburgh, K., Moreno-Mayar, J., Klein, R. G. 2017; 30: 53–69
  • Shellfishing and human evolution JOURNAL OF ANTHROPOLOGICAL ARCHAEOLOGY Klein, R. G., Bird, D. W. 2016; 44: 198-205
  • Issues in human evolution. Proceedings of the National Academy of Sciences of the United States of America Klein, R. G. 2016; 113 (23): 6345-7

    View details for DOI 10.1073/pnas.1606588113

    View details for PubMedID 27274040

    View details for PubMedCentralID PMC4988588

  • Shellfishing and Human Evolution Journal of Anthropological Archaeology Klein, R. G., Bird, D. W. 2016; 44: 198-205
  • Issues in Human Evolution Proceedings of the National Academy of Sciences Klein, R. G. 2016; 113: 6345-6347
  • The Middle and Later Stone Age faunal remains from Diepkloof Rock Shelter, Western Cape, South Africa JOURNAL OF ARCHAEOLOGICAL SCIENCE Steele, T. E., Klein, R. G. 2013; 40 (9): 3453-3462
  • Archaeological shellfish size and later human evolution in Africa PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Klein, R. G., Steele, T. E. 2013; 110 (27): 10910-10915


    Approximately 50 ka, one or more subgroups of modern humans expanded from Africa to populate the rest of the world. Significant behavioral change accompanied this expansion, and archaeologists commonly seek its roots in the African Middle Stone Age (MSA; ∼200 to ∼50 ka). Easily recognizable art objects and "jewelry" become common only in sites that postdate the MSA in Africa and Eurasia, but some MSA sites contain possible precursors, especially including abstractly incised fragments of ocher and perforated shells interpreted as beads. These proposed art objects have convinced most specialists that MSA people were behaviorally (cognitively) modern, and many argue that population growth explains the appearance of art in the MSA and its post-MSA florescence. The average size of rocky intertidal gastropod species in MSA and later coastal middens allows a test of this idea, because smaller size implies more intense collection, and more intense collection is most readily attributed to growth in the number of human collectors. Here we demonstrate that economically important Cape turban shells and limpets from MSA layers along the south and west coasts of South Africa are consistently and significantly larger than turban shells and limpets in succeeding Later Stone Age (LSA) layers that formed under equivalent environmental conditions. We conclude that whatever cognitive capacity precocious MSA artifacts imply, it was not associated with human population growth. MSA populations remained consistently small by LSA standards, and a substantial increase in population size is obvious only near the MSA/LSA transition, when it is dramatically reflected in the Out-of-Africa expansion.

    View details for DOI 10.1073/pnas.1304750110

    View details for Web of Science ID 000321978000024

    View details for PubMedID 23776248

    View details for PubMedCentralID PMC3704041

  • Stable carbon isotopes and human evolution. Proceedings of the National Academy of Sciences of the United States of America Klein, R. G. 2013; 110 (26): 10470-10472

    View details for DOI 10.1073/pnas.1307308110

    View details for PubMedID 23744041

    View details for PubMedCentralID PMC3696760

  • An early date for cattle from Namaqualand, South Africa: implications for the origins of herding in southern Africa ANTIQUITY Orton, J., Mitchell, P., Klein, R., Steele, T., Horsburgh, K. A. 2013; 87 (335): 108-120
  • Two Holocene rock shelter deposits from the Knersvlakte, southern Namaqualand, South Africa SOUTHERN AFRICAN HUMANITIES Orton, J., Klein, R. G., MacKay, A., Schwortz, S., Steele, T. E. 2011; 23: 109-150
  • Preface to the special issue-Early-Middle Pleistocene Palaeoenvironment in the Levant JOURNAL OF HUMAN EVOLUTION Klein, R. 2011; 60 (4): 319-319

    View details for DOI 10.1016/j.jhevol.2011.02.002

    View details for Web of Science ID 000289178700001

    View details for PubMedID 21392633

  • The abundance of eland, buffalo, and wild pigs in Middle and Later Stone Age sites JOURNAL OF HUMAN EVOLUTION Weaver, T. D., Steele, T. E., Klein, R. G. 2011; 60 (3): 309-314

    View details for DOI 10.1016/j.jhevol.2010.05.003

    View details for Web of Science ID 000288481300004

    View details for PubMedID 20875912

  • HILARY JOHN DEACON 1936-2010 In Memoriam SOUTH AFRICAN ARCHAEOLOGICAL BULLETIN Klein, R. G. 2010; 65 (191): 109-110
  • Comment on the Paleoenvironment of Ardipithecus ramidus SCIENCE Cerling, T. E., Levin, N. E., Quade, J., Wynn, J. G., Fox, D. L., Kingston, J. D., Klein, R. G., Brown, F. H. 2010; 328 (5982)


    White and colleagues (Research Articles, 2 October 2009, pp. 65-67 and characterized the paleoenvironment of Ardipithecus ramidus at Aramis, Ethiopia, which they described as containing habitats ranging from woodland to forest patches. In contrast, we find the environmental context of Ar. ramidus at Aramis to be represented by what is commonly referred to as tree- or bush-savanna, with 25% or less woody canopy cover.

    View details for DOI 10.1126/science.1185274

    View details for Web of Science ID 000278104700022

    View details for PubMedID 20508112

  • A Howiesons Poort tradition of engraving ostrich eggshell containers dated to 60,000 years ago at Diepkloof Rock Shelter, South Africa PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Texier, P., Porraz, G., Parkington, J., Rigaud, J., Poggenpoel, C., Miller, C., Tribolo, C., Cartwright, C., Coudenneau, A., Klein, R., Steele, T., Verna, C. 2010; 107 (14): 6180-6185


    Ongoing debates about the emergence of modern human behavior, however defined, regularly incorporate observations from the later part of the southern African Middle Stone Age and emphasize the early appearance of artifacts thought to reflect symbolic practice. Here we report a large sample of 270 fragments of intentionally marked ostrich eggshell from the Howiesons Poort at Diepkloof Rock Shelter, Western Cape, South Africa. Dating from approximately 60,000 years ago, these pieces attest to an engraving tradition that is the earliest reliable evidence of what is a widespread modern practice. These abstract linear depictions were made on functional items (eggshell containers), which were curated and involved in daily hunter-gatherer life. The standardized production of repetitive patterns, including a hatched band motif, suggests a system of symbolic representation in which collective identities and individual expressions are clearly communicated, suggesting social, cultural, and cognitive underpinnings that overlap with those of modern people.

    View details for DOI 10.1073/pnas.0913047107

    View details for Web of Science ID 000276374400013

    View details for PubMedCentralID PMC2851956

  • Morphometric identification of bovid metapodials to genus and implications for taxon-free habitat reconstruction JOURNAL OF ARCHAEOLOGICAL SCIENCE Klein, R. G., Franciscus, R. G., Steele, T. E. 2010; 37 (2): 389-401
  • Darwin and the recent African origin of modern humans PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Klein, R. G. 2009; 106 (38): 16007-16009

    View details for DOI 10.1073/pnas.0908719106

    View details for Web of Science ID 000270071600001

    View details for PubMedID 19805251

  • MOGAPELWA: ARCHAEOLOGY PALAEOENVIRONMENT AND ORAL TRADITIONS AT LAKE NGAMI, BOTSWANA SOUTH AFRICAN ARCHAEOLOGICAL BULLETIN Robbins, L. H., Campbell, A. C., Murphy, M. L., Brook, G. A., Mabuse, A. A., Hitchcock, R. K., Babutsi, G., Mmolawa, M., Stewart, K. M., Steele, T. E., Klein, R. G., Appleton, C. C. 2009; 64 (189): 13-32
  • Out of Africa and the Evolution of Human Behavior EVOLUTIONARY ANTHROPOLOGY Klein, R. G. 2008; 17 (6): 267-281

    View details for DOI 10.1002/evan.20181

    View details for Web of Science ID 000262150800005

  • Intertidal shellfish use during the Middle and Later Stone Age of South Africa ARCHAEOFAUNA Steele, T. E., Klein, R. G. 2008; 17: 63-76
  • Going strong, and growing JOURNAL OF ARCHAEOLOGICAL SCIENCE Rehren, T., Grattan, J., Klein, R. G. 2008; 35 (2): 213-213
  • Obituary - F. Clark Howell (1925-2007) JOURNAL OF ARCHAEOLOGICAL SCIENCE Klein, R. G., Butzer, K. W. 2007; 34 (9): 1552-1553
  • The mammalian fauna associated with an archaic hominin skullcap and later Acheulean artifacts at Elandsfontein, Western Cape Province, South Africa JOURNAL OF HUMAN EVOLUTION Klein, R. G., Avery, G., Cruz-Uribe, K., Steele, T. E. 2007; 52 (2): 164-186


    The Elandsfontein site, Western Cape Province, South Africa, is well known for an archaic hominin skullcap associated with later Acheulean artifacts. The site has also provided nearly 13,000 mammalian bones that can be identified to skeletal part and taxon. The assemblage derives from 49 species, 15 of which have no historic descendants. Comparisons to radiometrically dated faunas in eastern Africa indicate an age between 1 million and 600 thousand years ago. Unique features of the fauna, including the late occurrence of a dirk-toothed cat and a sivathere, may reflect its geographic origin in a region that was notable historically for its distinctive climate and high degree of biotic endemism. Together, taxonomic composition, geomorphic setting, and pollen extracted from coprolites indicate the proximity of a large marsh or pond, maintained by a higher water table. The small average size of the black-backed jackals implies relatively mild temperatures. The sum of the evidence places bone accumulation during one of the mid-Pleistocene interglacials that were longer and cooler than later ones, including the Holocene. The geomorphic context of the fauna presents no evidence for catastrophe, and most deaths probably resulted from attritional factors that disproportionately killed the young and old. However, only the dental-age profile of long-horned buffalo supports this directly. Field collection methods biased skeletal-part representation, but originally, it probably resembled the pattern in the younger, marsh-edge Acheulean occurrence at Duinefontein 2, 45 km to the south. Excavation there exposed multiple vertebral spreads, which probably mark carcasses from which hominins or large carnivores removed the meatier elements. Bone damage at both sites suggests that, despite abundant artifacts, hominins were much less important than carnivores in the bone accumulation. Together with limited observations from other sites, Elandsfontein and Duinefontein provisionally suggest that Acheulean-age hominins obtained few large mammals, whether by hunting or scavenging.

    View details for DOI 10.1016/j.jhevol.2006.08.006

    View details for Web of Science ID 000244619800004

    View details for PubMedID 17030056

  • The Ysterfontein 1 Middle Stone Age site, South Africa, and early human exploitation of coastal resources PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Klein, R. G., Avery, G., Cruz-Uribe, K., Halkett, D., Parkington, J. E., Steele, T., Volman, T. P., Yates, R. 2004; 101 (16): 5708-5715


    Human fossils and the genetics of extant human populations indicate that living people derive primarily from an African population that lived within the last 200,000 years. Yet it was only approximately 50,000 years ago that the descendants of this population spread to Eurasia, where they swamped or replaced the Neanderthals and other nonmodern Eurasians. Based on archaeological observations, the most plausible hypothesis for the delay is that Africans and Eurasians were behaviorally similar until 50,000 years ago, and it was only at this time that Africans developed a behavioral advantage. The archaeological findings come primarily from South Africa, where they suggest that the advantage involved much more effective use of coastal resources. Until now, the evidence has come mostly from deeply stratified caves on the south (Indian Ocean) coast. Here, we summarize results from recent excavations at Ysterfontein 1, a deeply stratified shelter in a contrasting environment on the west (Atlantic) coast. The Ysterfontein 1 samples of human food debris must be enlarged for a full comparison to samples from other relevant sites, but they already corroborate two inferences drawn from south coast sites: (i) coastal foragers before 50,000 years ago did not fish routinely, probably for lack of appropriate technology, and (ii) they collected tortoises and shellfish less intensively than later people, probably because their populations were smaller.

    View details for DOI 10.1073/pnas.0400528101

    View details for PubMedID 15007171

  • Paleoanthropology. Whither the Neanderthals? Science Klein, R. G. 2003; 299 (5612): 1525-1527

    View details for PubMedID 12624250

  • Whither the Neanderthals? SCIENCE Klein, R. G. 2003; 299 (5612): 1525-1527