Letter Open Access

Have We Been Barking up the Wrong Ancestral Tree? Australopithecines Are Probably Not Our Ancestors

Nature Anthropology. 2024, 2(1), 10007; https://doi.org/10.35534/natanthropol.2023.10007
Faculty of Medicine & Health Sciences, Ghent University, B9000 Ghent, Belgium
Kato Lechonia, 37300 Volos, Greece
National Museum of Australia, Canberra, ACT 2601, Australia
Studiecentrum Antropologie, B2580 Putte, Belgium
Authors to whom correspondence should be addressed.

Received: 12 Sep 2023    Accepted: 08 Dec 2023    Published: 15 Dec 2023   


The dominant paradigm regarding human evolution since the split with Pan considers australopithecines as hominins, i.e., the closest relatives and/or direct ancestors of Homo. Historically, this paradigm started from the assumption that the Homo/Pan/Gorilla last common ancestor was a knuckle-walking ape that evolved into the fully upright (orthograde), obligate bipedal genus Homo, whereas Pan and Gorilla remained knuckle-walkers. Obligate terrestrial upright bipedalism, unique for our species, is an odd locomotor behaviour for a primate. Therefore, it had become generally accepted that a cooler and drier African climate had caused deforestation, which had forced our ancestors to develop upright bipedalism as an adaptation to living on open grassland savannah. This view, already held by Lamarck and Darwin, appeared most parsimonious in the almost complete absence of fossils. The discovery in the 20th century of australopithecine fossils, bipedal apes with small brains, in open country in southern and eastern Africa corroborated the savannah paradigm. Therefore, australopithecines are considered hominins. However, it is now recognized that most australopithecines instead lived in a mosaic of forests, grasslands and wetlands, and better knowledge of their fossils clearly indicates that they possessed several climbing adaptations. Moreover, none of the extinct ape species older than Australopithecus and Paranthropus for which postcranial remains have been described (e.g., Morotopithecus, Sahelanthropus, Orrorin, Ardipithecus) were knuckle-walking. On the other hand, upright posture/gait is already present to different degrees even in Miocene apes. Moreover, the notion that hominoid orthogrady is a primitive characteristic is corroborated by the growing consensus that knuckle-walking is not a primitive trait but has evolved in parallel, independently in both Pan and Gorilla. Consequently, it is possible that australopithecines are not transitional between a semi-erect ancestor and upright bipedal humans, but to the contrary, are intermediate between a more upright ancestor and extant semi-erect African apes. In summary, hypotheses that attempt to explain how a semi-erect Homo/Pan last common ancestor transitioned into the bipedal australopithecines as an adaptation to life on the savannah appear to be ill-conceived and moreover seem to have been superfluous from the very start. We review the numerous similarities between australopithecines and extant African apes, suggesting that they are possibly not hominins and therefore not our direct ancestors. We suggest that we may have been barking up the wrong ancestral tree, for almost a century.


Tobias PV. Ape-like Australopithecus after seventy years: Was it a hominid?  J. Royal Anthropol. Inst. 1998, 4, 283–308. [Google Scholar]
Wood B, Richmond BG. Human evolution: taxonomy and paleobiology.  J. Anat. 2000, 196, 19–60. [Google Scholar]
Thorpe SK, Holder RL, Crompton RH. Origin of human bipedalism as an adaptation for locomotion on flexible branches.  Science 2007, 316, 1328–1331. [Google Scholar]
Crompton RH, Vereecke EE, Thorpe SKS. Locomotion and posture from the common hominoid ancestor to fully modern hominins, with special reference to the last common panin/hominin ancestor.  J. Anat. 2008, 212, 501–543. [Google Scholar]
Thorpe SKS, McClymont JM, Crompton RH. The arboreal origins of human bipedalism. Antiquity 2014, 88, 906–926. [Google Scholar]
Almécija S, Hammond AS, Thompson NE, Pugh KD, Moyà-Solà S, Alba DM. Fossil apes and human evolution.  Science 2021, 372, eabb4363. [Google Scholar]
Gebo DL, MacLatchy L, Kityo R, Deino A, Kingston J, Pilbeam D. A hominoid genus from the early Miocene of Uganda.  Science 1997, 276, 401–404. [Google Scholar]
White TD, Lovejoy CO, Asfaw B, Carlson JP, Suwa G. Neither chimpanzee nor human, Ardipithecus reveals the surprising ancestry of both.  Proc. Natl. Acad. Sci. USA 2015, 112, 4877–4884. [Google Scholar]
Verhaegen M, Puech P-F. Hominid lifestyle and diet reconsidered: Paleo-environmental and comparative data.  Hum. Evol. 2000, 15, 151–162. [Google Scholar]
Verhaegen M, Puech P-F, Munro S.  Aquarboreal ancestors?  Trends Ecol. Evol. 2002, 17, 212–217. [Google Scholar]
Verhaegen M, Munro S, Vaneechoutte M, Bender-Oser N, Bender R. The original econiche of Homo. In Ecology Research Progress; Nova Science Publishers: New York, NY, USA, 2007; pp. 1–34.
Verhaegen M, Munro S, Puech P-F, Vaneechoutte M. Early hominoids: Orthograde aquarboreals in flooded forests? In Was Man More Aquatic in the Past? Fifty Years after Alister Hardy—Waterside Hypotheses of Human Evolution; Bentham eBooks: Sharjah, UAE, 2011; pp. 67–81. 
Rosen KH, Jones CE, DeSilva JM. Bipedal locomotion in zoo apes: Revisiting the hylobatian model for bipedal origins.  Evol. Hum. Sci. 2022, 4, e12. [Google Scholar]
Dainton M, Macho GA. Did knuckle walking evolve twice? J. Hum. Evol. 1999, 36, 171–194. [Google Scholar]
Dainton M. Did our ancestors knuckle-walk?  Nature 2001, 410, 324–325. [Google Scholar]
Filler AG. The Upright Ape; Career Press: Franklin Lakes, NJ, USA, 2007.
Kivell TL, Schmitt D.  Independent evolution of knuckle-walking in African apes shows that humans did not evolve from a knuckle-walking ancestor.  Proc. Natl. Acad. Sci. USA 2009, 106, 14241–14246. [Google Scholar]
Morimoto N, Nakatsukasa M, Ponce de León MS, Zollikofer CPE. Femoral ontogeny in humans and great apes and its implications for their last common ancestor.  Sci. Rep. 2018, 8, 1930. [Google Scholar]
Simpson SW, Latimer B, Lovejoy CO. Why do knuckle‐walking African apes knuckle‐walk?  Anat. Rec. 2018, 301, 496–514. [Google Scholar]
Ward CV, Hammond AS, Plavcan JM, Begun DR. A late Miocene hominid partial pelvis from Hungary.  J. Hum. Evol. 2019, 136, 102645. [Google Scholar]
Crompton RH, Sellers W, Davids K, McClymont J. Biomechanics and the origins of human bipedal walking: The last 50 years.  J. Biomech. 2023, 157, 111701. [Google Scholar]
Morton DJ. Evolution of man’s erect posture (preliminary report).  J. Morphol. 1926, 43, 147–179. [Google Scholar]
Bender R, Tobias PV, Bender N. The savannah hypotheses: Origin, reception and impact on paleoanthropology.  Hist. Philos. Life Sci. 2012, 34, 147–184. [Google Scholar]
Kleindienst MR, Burton FD, Kortlandt A. On new perspectives on ape and human evolution.  Curr. Anthropol. 1975, 16, 644–651. [Google Scholar]
Oxnard CE. The place of the australopithecines in human evolution: Grounds for doubt?  Nature 1975, 258, 389–395. [Google Scholar]
Gribbin JR, Cherfas J. The Monkey Puzzle: Reshaping the Evolutionary Tree; Pantheon: New York City, NY, USA, 1982.
Edelstein SJ. An alternative paradigm for hominoid evolution.  Hum. Evol. 1987, 2, 169–174. [Google Scholar]
Verhaegen MJB. African ape ancestry.  Hum. Evol. 1990, 5, 295–297. [Google Scholar]
Verhaegen MJB. Australopithecines: Ancestors of the African apes?  Hum. Evol. 1994, 9, 121–139. [Google Scholar]
Verhaegen M. Morphological distance between australopithecine, human and ape skulls.  Hum. Evol. 1996, 11, 35–41. [Google Scholar]
Gribbin J, Cherfas J. The First Chimpanzee. In Search of Human Origins; Penguin Books: London, UK, 2001.
Pickford M, Senut B, Gommery D, Treil J. Bipedalism in Orrorin tugenensis revealed by its femora.  C. R. Palevol. 2002, 1, 191–203. [Google Scholar]
Dawkins R, Wong Y. The Ancestor’s Tale. The Dawn of Evolution; Houghton Mifflin Hartcourt: Boston, NY, USA, 2016.
Hunt KD. The evolution of human bipedality: Ecology and functional morphology.  J. Hum. Evol. 1994, 26, 183–202. [Google Scholar]
Hunt KD. The postural feeding hypothesis: An ecological model for the evolution of bipedalism.  S. Afr. J. Sci. 1996, 92, 77–90. [Google Scholar]
Stamos PA, Alemseged Z. Hominin locomotion and evolution in the Late Miocene to Late Pliocene.  J. Human Evol. 2023, 178, 103332. [Google Scholar]
de Lamarck J-B. Zoological Philosophy; An Exposition with Regard to the Natural History of Animals; MacMillan & Co: London, UK, 1914.
Mayr E. The Growth of Biological Thought: Diversity, Evolution, and Inheritance; Harvard University Press: Cambridge, MT, USA, 1982.
Delisle RG. Debating humankind’s place in Nature. In The Nature of Paleoanthropology; Pearson Prentice Hall: Upper Saddle River, NJ, USA, 2007; pp. 1860–2000.
Darwin C. The Descent of Man and Selection in Relation to Sex; John Murray: London, UK, 1871.
Wallace AR. Darwinism: An Exposition of the Theory of Natural Selection with Some of its Applications; Macmillan: London, UK, 1889.
Steinmann G. Die Geologischen Grundlagen der Abstammungslehre; Engelmann: Leipzig, Germany, 1908.
Barrell J. Probable relations of climatic change to the origin of the Tertiary ape-man.  Sci. M. 1908, 4, 16–26. [Google Scholar]
Ruff CB, Burgess ML, Ketcham RA, Kappelman J. Limb bone structural proportions and locomotor behavior in A.L. 288-1 (“Lucy”).  PLoS ONE 2016, 11, e0166095. [Google Scholar]
Dart R. Australopithecus africanus, the man-ape of South Africa. Nature 1925, 115, 195–199. [Google Scholar]
Sussman RW. The myth of Man the Hunter, Man the Killer and the evolution of human morality.  Zygon 1999, 34, 453–471. [Google Scholar]
R.J.G.S. C.K. Brain 1981. The Hunters or the Hunted? An Introduction to African Cave Taphonomy. x + 365 pp., 226 figs. 121 figures. Chicago, London: The University of Chicago Press. Price £24.50. ISBN 0 226 07089 1.  Geol. Mag. 1983, 120, 92–93. [Google Scholar]
Maguire JM. Recent geological, stratigraphic and palaeontological studies at Makapansgat Limeworks. In Hominid Evolution: Past, Present and Future; Alan R. Liss: New York, NY, USA, 1985, pp. 151–164.
Reed KE. Early hominid evolution and ecological change through the African Plio-Pleistocene.  J. Hum. Evol. 1997, 32, 289–322. [Google Scholar]
Lindshield S, Hernandez‐Aguilar RA, Korstjens AH, Marchant LF, Narat V, Ndiaye PI, et al. Chimpanzees (Pan troglodytes) in savanna landscapes.  Evol. Anthropol. 2021, 30, 399–420. [Google Scholar]
Keith A.  The Taungs skull.  Nature 1925, 116, 11. [Google Scholar]
Woodward AS. The fossil anthropoid ape from Taungs.  Nature 1925, 115, 235–236. [Google Scholar]
Broom R. The Coming of Man: Was it Accident or Design? Witherby: London, UK, 1933.
Ardrey R. African Genesis: A Personal Investigation into the Animal Origins and Nature of Man; Atheneum: New York, NY, USA, 1961.
Ardrey R. The Hunting Hypothesis: A Personal Conclusion Concerning the Evolutionary Nature of Man; Atheneum: New York, NY, USA, 1976.
Johnson EM. The better bonobos of our nature, 2012. Available online: https://blogs.scientificamerican.com/primate-diaries/the-better-bonobos-of-our-nature/ (accessed on 6 September 2023).
Wrangham R, Peterson D. Demonic Males: Apes and the Origins of Human Violence; Houghton Miflin: Boston, NY, USA, 1996.
Johanson DC, White TD, Coppens Y. A new species of the genus Australopithecus (Primates: Hominidae) from the Pliocene of Eastern Africa”.  Kirtlandia 1978, 28, 1–14. [Google Scholar]
Johanson DC, Edey MA. Lucy: The Beginnings of Humankind; Simon & Schuster: New York, NY, USA, 1981.
Coppens Y. East side story, the origin of humankind.  Sci. Am. 1994, 270, 88–95. [Google Scholar]
Brunet M, Beauvillain A, Coppens Y, Heintz E, Moutaye AHE, Pilbeam D. The first australopithecine 2,500 kilometres west of the Rift Valley (Chad). Nature 1995, 378, 273–275. [Google Scholar]
Coppens Y. L’East Side Story n’existe plus.  La Recherche 2003, 361, 74–78. [Google Scholar]
Raynaud B. 2020. Le blog. Yves Coppens, the interview 2/3. 5th of August 2020. Available online: https://benjaminraynaudleblog.wordpress.com/2020/08/05/yves-coppens-the-interview-2-3/ (accessed on 7 September 2023).
Leakey R, Lewontin R. Origins Reconsidered; Little Brown: London, UK, 1992.
Radosevich SC, Retallack GJ, Taieb M. Reassessment of the paleoenvironment and preservation of hominid fossils from Hadar, Ethiopia.  Am. J. Phys. Anthropol. 1992, 87, 15–27. [Google Scholar]
Tobias PV. ‘Little Foot’ and the bearing of recent South African researches on the status of Australopithecus africanus. In Was Man More Aquatic in the Past? Fifty Years after Alister Hardy. Waterside Hypotheses of Human Evolution; Bentham eBooks: Sharjah, UAE, 2011, pp. 3–15.
de Menocal PB. African climate change and faunal evolution during the Pliocene–Pleistocene.  Earth Planet. Sci. Lett. 2004, 220, 3–24. [Google Scholar]
White TD. Reply to: Dominguez-Rodrigo M. Is the “Savanna hypothesis” a dead concept for explaining the emergence of the earliest hominins?  Curr. Anthropol. 2014, 55, 59–69. [Google Scholar]
Brunet M, Guy F, Pilbeam D, Mackaye HT, Likius A, Ahounta D, et al. A new hominid from the Upper Miocene of Chad, Central Africa.  Nature 2002, 418, 145–151. [Google Scholar]
Sevim-Erol A, Begun DR, Sözer ÇS, Mayda S, van den Hoek Ostende LW, Martin RMG, et al. A new ape from Türkiye and the radiation of late Miocene hominines.  Commun. Biol. 2023, 6, 842. [Google Scholar]
Brunet M.  Sahelanthropus or ‘Sahelpithecus’? Reply to Wolpoff et al. Nature 2002, 419, 582. [Google Scholar]
White T, Suwa G, Asfaw B. Australopithecus ramidus, a new species of early hominid from Aramis, Ethiopia.  Nature 1994, 371, 306–312. [Google Scholar]
Lovejoy CO. Reexamining human origins in light of Ardipithecus ramidus. Science 2009, 326, 74e1–74e8.
Hasegawa M, Kishino H, Yano T. Dating of the human-ape splitting by a molecular clock of mitochondrial DNA.  J. Mol. Evol. 1985, 22, 160–174. [Google Scholar]
Keith A. Hunterian Lectures on Man’s posture: Its evolution and disorders: Given at the Royal College of Surgeons of England.  Brit. Med. J. 1923, 1, 451–454. [Google Scholar]
Tuttle RH. Knuckle-walking and the problem of human origins.  Science 1969, 166, 953–961. [Google Scholar]
Begun D. Miocene fossil hominids and the chimp-human clade.  Science 1992, 257, 1929–1933. [Google Scholar]
Richmond BG, Strait DS. Evidence that humans evolved from a knuckle walking ancestor.  Nature 2000, 404, 382–385. [Google Scholar]
Williams SA. Morphological integration and the evolution of knuckle-walking. J. Hum. Evol. 2010, 58, 432–440. [Google Scholar]
Schultz AH. The position of the occipital condyles and of the face relative to the skull base in primates.  Am. J. Phys. Anthropol. 1955, 13, 97–120. [Google Scholar]
McCollum MA, Rosenman BA, Suwa G, Meindl RS, Lovejoy CO. The vertebral formula of the last common ancestor of African apes and humans.  J. Exp. Zool. Mol. Dev. Evol. 2010, 314, 123–134. [Google Scholar]
Leakey REF, Mungai JM, Walker AC. New australopithecines from East Rudolf, Kenya.  Am. J. Phys. Anthropol. 1971, 35, 175–186. [Google Scholar]
Du A, Alemseged Z. Temporal evidence shows Australopithecus sediba is unlikely to be the ancestor of Homo.  Sci. Adv. 2019, 5, eaav9038. [Google Scholar]
Ferguson WW. A new species of the genus Australopithecus (Primates-Hominidae) from the Plio/Pleistocene deposits West of Lake Turkana in Kenya.  Primates 1989, 30, 223–232. [Google Scholar]
Hrdlička A. The Taungs ape.  Am. J. Phys. Anthrop. 1925, 8, 379. [Google Scholar]
Grine FE, Kay RF. Early hominid diets from quantitative image analysis of dental microwear.  Nature 1988, 333, 765–768. [Google Scholar]
McCollum MA. The robust australopithecine face: A morphogenetic perspective. Science 1999, 284, 301–305. [Google Scholar]
Martin L. Significance of enamel thickness in hominoid evolution.  Nature 1985, 314, 260–263. [Google Scholar]
Simons E. Human origins.  Science 1989, 245, 1343–1350. [Google Scholar]
Bromage T, Dean M. Re-evaluation of the age at death of immature fossil hominids. Nature 1985, 317, 525–527. [Google Scholar]
Bromage TG. Taung facial remodelling: a growth and development study. In Evolution; Alan R. Liss: New York, NY, USA, 1985, pp. 239–245.
Smith BH. Dental development in Australopithecus and early Homo Nature 1986, 323, 327–330. [Google Scholar]
Conroy GC, Vannier MW. Dental development of the Taung skull from computerized tomography.  Nature 1987, 329, 625–627. [Google Scholar]
Conroy GC, Vannier MW. The nature of Taung dental maturation continued.  Nature 1988, 333, 808. [Google Scholar]
Beynon AD, Dean MC. Distinct dental development patterns in early fossil hominids.  Nature 1988, 335, 509–514. [Google Scholar]
Conroy GC, Kuykendall K. Paleopediatrics: Or when did human infants really become human?  Am. J. Phys. Anthropol. 1995, 98, 121–131. [Google Scholar]
Smith HB. Patterns of dental development in Homo, Australopithecus, Pan, and Gorilla.  Am. J. Phys. Anthropol. 1994, 94, 307–325. [Google Scholar]
Zihlman AL, Cronin JE, Cramer DL, Sarich VM. Pygmy chimpanzee as a possible prototype for the common ancestor of humans, chimpanzees and gorillas.  Nature 1978, 275, 744–746. [Google Scholar]
Munro S, Verhaegen M. Pachyosteosclerosis in archaic Homo: Heavy skulls for diving, heavy legs for wading? In Was Man More Aquatic in the Past? Fifty Years after Alister Hardy—Waterside Hypotheses of Human Evolution; Bentham eBooks: Sharjah, UAE, 2011; pp. 82–105.
Crowell MG, Rahmat S, Koretsky I. Correlation of bone density in semi-aquatic and aquatic animals with ecological and dietary specializations.  FASEB J. 2020, 34, 1. [Google Scholar]
Rak Y, Ginzburg A, Geffen A.  Gorilla-like anatomy on Australopithecus afarensis mandibles suggests Au. afarensis link to robust australopiths.  Proc. Natl. Acad. Sci. USA 2007, 104, 6568–6572. [Google Scholar]
Campbell RM, Vinas G, Henneberg M. Relationships between the hard and soft dimensions of the nose in Pan troglodytes and Homo sapiens reveal the positions of the nasal tips of Plio-Pleistocene hominids.  PLoS ONE 2022, 17, e0259329. [Google Scholar]
Schultz AH. Growth and development of the orang-utan. Contrib. Embryol. 1941, XXIX, 57–110.
Eckhardt R. Hominoid nasal region polymorphism and its phylogenetic significance.  Nature 1987, 328, 333–335. [Google Scholar]
McCollum MA. Subnasal morphological variation in fossil hominids: A reassessment based on new observations and recent developmental findings.  Am. J. Phys. Anthropol. 2000, 112, 275–283. [Google Scholar]
Kimbel WH, White TD, Johanson DC. Cranial morphology of Australopithecus afarensis: A comparative study based on a composite reconstruction of the adult skull.  Am. J. Phys. Anthropol. 1984, 64, 337–388. [Google Scholar]
Dunn JC. Sexual selection and the loss of laryngeal air sacs during the evolution of speech.  Anthropol. Sci. 2018, 126, 29–34. [Google Scholar]
Alemseged Z, Spoor F, Kimbel WH, Bobe R, Geraads D, Reed D, et al. A juvenile early hominin skeleton from Dikika, Ethiopia.  Nature 2006, 443, 296–301. [Google Scholar]
de Boer B. Loss of air sacs improved hominin speech abilities.  J. Hum. Evol. 2012, 62, 1–6. [Google Scholar]
Masters AV, Falk D, Gage TB. Effects of age and gender on the location and orientation of the foramen magnum in rhesus macaques (Macaca mulata).  Am. J. Phys. Anthropol. 1991, 86, 75–80. [Google Scholar]
Ashton EH, Zuckerman S. Age changes in the position of the occipital condyles in the gorilla.  Am. J. Phys. Anthropol. 1952, 10, 277–288. [Google Scholar]
Kimbel WH, Rak Y.  The cranial base of Australopithecus afarensis: New insights from the female skull.  Philos. Trans. R. Soc. B 2010, 365, 3365–3376. [Google Scholar]
Landi F, Profico A, Veneziano A, De Groote I, Manzi G. Locomotion, posture, and the foramen magnum in primates: Reliability of indices and insights into hominin bipedalism.  Am. J. Primatol. 2020, 82, e23170. [Google Scholar]
Bastir M, Rosas A. Mosaic evolution of the basicranium in Homo and its relation to modular development.  Evol. Biol. 2009, 36, 57–70. [Google Scholar]
Raia P, Boggioni M, Carotenuto F, Castiglione S, Di Febbraro M, Di Vincenzo F, et al. Unexpectedly rapid evolution of mandibular shape in hominins.  Sci. Rep. 2018, 8, 7340. [Google Scholar]
Wood B, Harrison T. The evolutionary context of the first hominins.  Nature 2011, 470, 347–352. [Google Scholar]
Spoor F, Wood B, Zonneveld F. Implications of early hominid labyrinthine morphology for evolution of human bipedal locomotion.  Nature 1994, 369, 645–648. [Google Scholar]
Bramble DM, Lieberman DE.  Endurance running and the evolution of Homo Nature 2004, 432, 345–352. [Google Scholar]
Vaneechoutte M. The origin of articulate language revisited: The potential of a semi-aquatic past of human ancestors to explain the origin of human musicality and articulate language.  Hum. Evol. 2014, 29, 1–33. [Google Scholar]
Kimbel WH, Villmoare B. From Australopithecus to Homo: the transition that wasn’t.  Philos. Trans. R. Soc. B 2016, 371, 20150248. [Google Scholar]
Grabowski M, Voje KL, Hansen TF. Evolutionary modeling and correcting for observation error support a 3/5 brain-body allometry for primates.  J. Hum. Evol. 2016, 94, 106–116. [Google Scholar]
Gunz P, Neubauer S, Falk D, Tafforeau P, Le Cabec A, Smith TM, et al. Australopithecus afarensis endocasts suggest ape-like brain organization and prolonged brain growth.  Sci. Adv. 2020, 6, eaaz4729. [Google Scholar]
Cofran Z. Brain size growth in Australopithecus J. Hum. Evol. 2019, 130, 72–82. [Google Scholar]
Falk D. Ape-like endocast of “ape-man” Taung.  Am. J. Phys. Anthropol. 1989, 80, 335–339. [Google Scholar]
Kano T. The Last Ape: Pygmy Chimpanzee Behavior and Ecology; Stanford University Press: Stanford, CA, USA, 1992.
Zihlman A.  Pygmy chimps, people, and the pundits.  New Sci. 1984, 104, 39–40. [Google Scholar]
Green DJ, Gordon AD, Richmond BG. Limb-size proportions in Australopithecus afarensis and Australopithecus africanus J. Hum. Evol. 2007, 52, 187–200. [Google Scholar]
Reno PL, Meindl RS, McCollum MA, Lovejoy CO. Sexual dimorphism in Australopithecus afarensis was similar to that of modern humans.  Proc. Natl. Acad. USA 2003, 100, 9404–9409. [Google Scholar]
Schultz AH. The Life of Primates; Universe Books: New York, NY, USA, 1969.
Lee S-H. Patterns of size sexual dimorphism in Australopithecus afarensis: another look.  Homo 2005, 56, 219–232. [Google Scholar]
Stern JT Jr, Susman RL. The locomotor anatomy of Australopithecus afarensis Am. J. Phys. Anthropol. 1983, 60, 279–317. [Google Scholar]
Chirchir H, Kivell TL, Ruff CB, Hublin JJ, Carlson KJ, Zipfel B, et al. Recent origin of low trabecular bone density in modern humans.  Proc. Nat. Acad. Sci. USA 2015, 112, 366–371. [Google Scholar]
Lewin R. The earliest “humans” were more like apes.  Science 1987, 236, 1061–1063. [Google Scholar]
Roffman I, Nevo E. Can chimpanzee biology highlight human origin and evolution?  Rambam Maimonides Med. J. 2010, 1, e0009. [Google Scholar]
Rolian C, Gordon AD. Reassessing manual proportions in Australopithecus afarensis Am. J. Phys. Anthropol. 2013, 152, 393–406. [Google Scholar]
McPherron SP, Alemseged Z, Marean CW, Wynn JG, Reed D, Geraads D, et al. Evidence for stone-tool-assisted consumption of animal tissues before 3.39 million years ago at Dikika, Ethiopia.  Nature 2010, 466, 857–860. [Google Scholar]
Goodall J. The Chimpanzees of Gombe: Patterns of Behavior; Harvard University Press: Cambridge, MA, USA, 1986.
Mercader J, Barton H, Gillespie J, Harris J, Kuhn S, Tyler R, et al. 4300-Year-old chimpanzee sites and the origins of percussive stone technology.  Proc. Natl. Acad. Sci. USA 2007, 104, 3043–3048. [Google Scholar]
Fernandes MEB. Tool use and predation of oysters by the tufted capuchin in brackish water mangrove swamp.  Primates 1991, 32, 529–531. [Google Scholar]
Falótico T, Proffitt T, Ottoni EB, Staff RA, Haslam M. Three thousand years of wild capuchin stone tool use.  Nat. Ecol. Evol. 2019, 3, 1034–1038. [Google Scholar]
Motes-Rodrigo A, McPherron SP, Archer W, Hernandez-Aguilar RA, Tennie C. Experimental investigation of orangutans’ lithic percussive and sharp stone tool behaviours.  PLoS ONE 2022, 17, e0263343. [Google Scholar]
Walker A, Leakey R. The Nariokotome Homo erectus Skeleton; Harvard University Press: Cambridge, MA, USA, 1993.
Straus WL. Studies in primate ilia.  Am. J. Anat. 1929, 43, 403–460. [Google Scholar]
Lovejoy CO. Natural history of human gait and posture. Part 1. Spine and pelvis.  Gait Posture 2005, 21, 95–112. [Google Scholar]
Steudel KL. Locomotor energetics and hominid evolution.  Evol. Anthropol. 1994, 3, 42–48. [Google Scholar]
Verhaegen M, Munro S. The continental shelf hypothesis.  Nutr. Health 2002, 16, 25–27. [Google Scholar]
Harcourt-Smith WEH. Early hominin diversity and the emergence of the genus Homo J. Anthropol. Sci. 2016, 94, 19–27. [Google Scholar]
Berillon G. In what manner did they walk on two legs? In From Biped to Strider; Springer: Boston, MA, USA, 2004, pp. 85–100.
Leakey MD, Hay RL. Pliocene footprints in the Laetolil Beds at Laetoli, northern Tanzania. Nature 1979, 278, 317–323. [Google Scholar]
Meldrum DJ, Lockley MG, Lucas SG, Musiba C. Ichnotaxonomy of the Laetoli trackways: The earliest hominin footprints.  J. Afr. Sci. 2011, 60, 1–12. [Google Scholar]
Harcourt-Smith WEH. The origins of bipedal locomotion. In Handbook of Paleoanthropology; Springer: Berlin, Germany, 2013, pp. 1–36.
1Harper CM, Ruff CB, Sylvester AD. Calcaneal shape variation in humans, nonhuman primates, and early hominins.  J. Hum. Evol. 2021, 159, 103050. [Google Scholar]
Anaya A, Patel BA, Orr CM, Ward CV, Almécija S. Evolutionary trends of the lateral foot in catarrhine primates: Contextualizing the fourth metatarsal of Australopithecus afarensis J. Hum. Evol. 2021, 161, 103078. [Google Scholar]
Harcourt-Smith WE, Aiello LC. Fossils, feet and the evolution of human bipedal locomotion.  J. Anat. 2004, 204, 403–416. [Google Scholar]
Rein TR, Harrison T, Carlson KJ, Harvati K. Adaptation to suspensory locomotion in Australopithecus sediba J. Hum. Evol. 2017, 104, 1–12. [Google Scholar]
Wiseman ALA. Three-dimensional volumetric muscle reconstruction of the Australopithecus afarensis pelvis and limb, with estimations of limb leverage.  R. Soc. Open Sci. 2023, 10, 230356. [Google Scholar]
Prado-Martinez J, Sudmant PH, Kidd JM, Li H, Kelley JL, Lorente-Galdos B, et al. Great ape genetic diversity and population history.  Nature 2013, 499, 471–475. [Google Scholar]
Pilbeam D. Genetic and morphological records of the Hominoidea and hominid origins: A synthesis.  Mol. Phylogenet. Evol. 1996, 5, 155–168. [Google Scholar]
Zihlman AL, Bolter DR. Body composition in Pan paniscus compared with Homo sapiens has implications for changes during human evolution.  Proc. Natl. Acad. Sci. USA 2015, 112, 7466–7471. [Google Scholar]
Yohn CT, Jiang Z, McGrath SD, Hayden KE, Khaitovich P, Johnson ME, et al. Lineage-specific expansions of retroviral insertions within the genomes of African great apes but not humans and orangutans.  PLoS Biol. 2005, 3, 1–11. [Google Scholar]
Kaiser SM, Malik HS, Emerman M. Restriction of an extinct retrovirus by the human TRIM5 antiviral protein.  Science 2007, 316, 1756–1758. [Google Scholar]
Benveniste RE, Todaro GJ. Evolution of type C viral genes. Evidence for an Asian origin of man.  Nature 1976, 261, 101–108. [Google Scholar]
Perez-Caballero D, Soll SJ, Bieniasz PD. Evidence for restriction of ancient primate gammaretroviruses by APOBEC3 but not TRIM5α proteins.  PLoS Pathog. 2008, 4, e1000181. [Google Scholar]
Joordens JCA, Feibel CS, Vonhof HB, Schulp AS, Kroon D. Relevance of the eastern African coastal forest for early hominin biogeography.  J. Hum. Evol. 2019, 131, 176–202. [Google Scholar]
Speth JD. Early hominid hunting and scavenging: The role of meat as an energy source.  J. Hum. Evol. 1989, 18, 329–343. [Google Scholar]
Derricourt R. The enigma of Raymond Dart.  Int. J. Afr. Hist. Stud. 2009, 42, 257–282. [Google Scholar]
Antón SC, Potts R, Aiello LC. Evolution of early Homo: An integrated biological perspective.  Science 2014, 344, 1236828. [Google Scholar]
Dominguez-Rodrigo M. Is the “Savanna hypothesis” a dead concept for explaining the emergence of the earliest hominins?  Curr. Anthropol. 2014, 55, 59–69. [Google Scholar]
Morgan E. The Aquatic Ape Hypothesis; Souvenir Press: London, UK, 1997.
Schweitzer MH, Schroeter ER, Cleland TP, Zheng W. Paleoproteomics of Mesozoic dinosaurs and other Mesozoic fossils.  Proteomics 2019, 19, 1800251. [Google Scholar]
Creative Commons

© 2024 by the authors; licensee SCIEPublish, SCISCAN co. Ltd. This article is an open access article distributed under the CC BY license (https://creativecommons.org/licenses/by/4.0/).