Origins and Evolution of Genus Homo: New Perspectives

Susan C. Antón and J. Josh Snodgrass
Current Anthropology
Vol. 53, No. S6, Human Biology and the Origins of Homo (December 2012), pp. S479-S496
DOI: 10.1086/667692
Stable URL:
Page Count: 18
  • Download PDF
  • Cite this Item

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:


Log in to your personal account or through your institution.

Origins and Evolution of Genus Homo
We're having trouble loading this content. Download PDF instead.


Recent fossil and archaeological finds have complicated our interpretation of the origin and early evolution of genus Homo. Using an integrated data set from the fossil record and contemporary human and nonhuman primate biology, we provide a fresh perspective on three important shifts in human evolutionary history: (1) the emergence of Homo, (2) the transition between non-erectus early Homo and Homo erectus, and (3) the appearance of regional variation in H. erectus. The shift from Australopithecus to Homo was marked by body and brain size increases, a dietary shift, and an increase in total daily energy expenditure. These shifts became more pronounced in H. erectus, but the transformation was not as radical as previously envisioned. Many aspects of the human life history package, including reduced dimorphism, likely occured later in evolution. The extant data suggest that the origin and evolution of Homo was characterized by a positive feedback loop that drove life history evolution. Critical to this process were probably cooperative breeding and changes in diet, body composition, and extrinsic mortality risk. Multisystem evaluations of the behavior, physiology, and anatomy of extant groups explicitly designed to be closely proxied in the fossil record provide explicit hypotheses to be tested on future fossil finds.

Notes and References

This item contains 130 references.

References Cited
  • ['Aiello, Leslie C., and Susan C. Antón. 2012. Human biology and the origins of Homo: an introduction to supplement 6. Current Anthropology 53(suppl. 6):S269–S277.']
  • ['Aiello, Leslie C., and Peter Wheeler. 1995. The expensive-tissue hypothesis: the brain and the digestive system in human and primate evolution. Current Anthropology 36:199–221.']
  • ['Altmann, Jeanne, and Susan C. Alberts. 2005. Growth rates in a wild primate population: ecological influences and maternal effects. Behavioral Ecology and Sociobiology 57:490–501.']
  • ['Antón, Susan C. 2003. A natural history of Homo erectus. Yearbook of Physical Anthropology 46:126–170.']
  • ['———. 2008. Framing the question: diet and evolution in early Homo. In Primate craniofacial function and biology. Christopher J. Vinyard, Matthew J. Ravosa, and Christine E. Wall, eds. Pp. 443–482. New York: Springer.']
  • ['———. 2012. Early Homo: who, when, and where. Current Anthropology 53(suppl. 6):S278–S298.']
  • ['Antón, Susan C., William R. Leonard, and Marcia Robertson. 2002. An ecomorphological model of the initial hominid dispersal from Africa. Journal of Human Evolution 43:773–785.']
  • ['Antón, Susan C., and Carl C. Swisher III. 2004. Early dispersals of Homo from Africa. Annual Reviews of Anthropology 33:271–296.']
  • ['Blumenschine, Robert J., Charles C. Peters, Fidelis T. Masao, Ron J. Clarke, Alan L. Deino, Richard L. Hay, Carl C. Swisher, et al. 2003. Late Pliocene Homo and hominid land use from western Olduvai Gorge, Tanzania. Science 299:1217–1221.']
  • ['Boas, Franz. 1912. Changes in bodily form of descendants of immigrants. New York: Columbia University Press.']
  • ['Bogin, Barry B. 1999. Patterns of human growth. 2nd edition. Cambridge: Cambridge University Press.']
  • ['———. 2006. Modern human life history: the evolution of human childhood and fertility. In The evolution of human life history. Kristen Hawkes and Richard R. Paine, eds. Pp. 197–230. Santa Fe, NM: School of American Research.']
  • ['Bogin, Barry, and Luis Rios. 2003. Rapid morphological change in living humans: implications for modern human origins. Comparative Biochemistry and Physiology 136A:71–84.']
  • ['Bogin, Barry, and B. Holly Smith. 1996. Evolution of the human life cycle. American Journal of Human Biology 8:703–716.']
  • ['Bogin, Barry, and Maria Inês Varela-Silva. 2010. Leg length, body proportions, and health: a review with a note on beauty. International Journal of Environmental Research and Public Health 7:1047–1075.']
  • ['Borries, Carola, Amy Lu, Kerry Ossi-Lupo, Eileen Larney, and Andreas Koenig. 2011. Primate life histories and dietary adaptations: a comparison of Asian colobines and macaques. American Journal of Physical Anthropology 144:286–299.']
  • ['Braun, David R., Thomas Plummer, Peter Ditchfield, Joseph V. Ferraro, David Maina, Laura C. Bishop, and Richard Potts. 2008. Oldowan behavior and raw material transport: perspectives from the Kanjera Formation. Journal of Archaeological Science 35:2329–2345.']
  • ['Bribiescas, Richard G., Peter T. Ellison, and Peter B. Gray. 2012. Male life history, reproductive effort, and the evolution of the genus Homo. Current Anthropology 53(suppl. 6):S424–S435.']
  • ['Calder, William A. 1984. Size, function, and life history. Cambridge, MA: Harvard University Press.']
  • ['Charnov, Eric L. 1993. Life history invariants: some explanations of symmetry in evolutionary ecology. Oxford: Oxford University Press.']
  • ['Clegg, Margaret, and Leslie C. Aiello. 1999. A comparison of the Nariokotome Homo erectus with juveniles from a modern human population. American Journal of Physical Anthropology 110:81–93.']
  • ['Clutton-Brock, Tim. 2009. Cooperation between non-kin in animal societies. Nature 462:51–57.']
  • ['Collard, Mark, and Bernard Wood. 2007. Defining the genus Homo. In Phylogeny of hominids, vol. 3. of Handbook of paleoanthropology. Winfried Henke and Ian Tattersall, eds. Pp. 1575–1611. Berlin: Springer.']
  • ['Copeland, Sandy R., Matthew Sponheimer, Darryl J. de Ruiter, Julia A. Lee-Thorp, Daryl Codron, Petrus J. le Roux, Vaughan Grimes, and Michael P. Richards. 2011. Strontium isotope evidence for landscape use by early hominins. Nature 474:76–79.']
  • ['Dean, Christopher, Meave G. Leakey, Don Reid, Friedemann Schrenk, Gary T. Schwartz, Christopher Stringer, and Alan Walker. 2001. Growth processes in teeth distinguish modern humans from Homo erectus and earlier hominins. Nature 414:628–631.']
  • ['Dean, Christopher, and B. Holly Smith. 2009. Growth and development of the Nariokotome youth, KNM-WT 15000. In The first humans: origin and early evolution of the genus Homo. Fred E. Grine, John G. Fleagle, and Richard E. Leakey, eds. Pp. 101–120. New York: Springer.']
  • ['Dirks, Wendy, and Jacqui E. Bowman. 2007. Life history theory and dental development in four species of catarrhine primates. Journal of Human Evolution 53:309–320.']
  • ['Domínguez-Rodrigo, Manuel, Travis R. Pickering, and Henry T. Bunn. 2010. Configurational approach to identifying the earliest hominin butchers. Proceedings of the National Academy of Sciences of the USA 107(49):20929–20934.']
  • ['———. 2011. Reply to McPherron et al.: doubting Dikika is about data, not paradigms. Proceedings of the National Academy of Sciences of the USA 108(21):E117.']
  • ['Ellison, Peter T. 2008. Energetics, reproductive ecology, and human evolution. Paleoanthropology 2008:172–200.']
  • ['Eveleth, Phyllis B., and James M. Tanner. 1990. Worldwide variation in human growth. 2nd edition. Cambridge: Cambridge University Press.']
  • ['Fernandez-Duque, Eduardo. 2011. Rensch’s rule, Bergman’s effect and adult sexual dimorphism in wild monogamous owl monkeys of Argentina. American Journal of Physical Anthropology 146:38–48.']
  • ['Flinn, Mark V. 2010. Evolutionary biology of hormonal responses to social challenges in the human child. In Human evolutionary biology. Michael P. Muehlenbein, ed. Pp. 405–424. Cambridge: Cambridge University Press.']
  • ['Floyd, Bruce, and Judith Littleton. 2006. Linear enamel hypoplasia and growth in an Australian Aboriginal community: not so small, but not so healthy either. Annals of Human Biology 33:424–443.']
  • ['Frisancho, A. Roberto, Stanley M. Garn, and Werner Ascoli. 1970. Unequal influence of low dietary intakes on skeletal maturation during childhood and adolescence. American Journal of Clinical Nutrition 23:1220–1227.']
  • ['Gabunia, Leo, Abesalom Vekua, David Lordkipanidze, Carl C. Swisher, Reid Ferring, Antje Justus, Medea Nioradze, et al. 2000. Earliest Pleistocene cranial remains from Dmanisi, Republic of Georgia: taxonomy, geological setting, and age. Science 288:1019–1025.']
  • ['Gaur, Rajan, and Pawan Kumar. 2012. Effect of undernutrition on deciduous tooth emergence among Rajput children of Shimla District of Himachal Pradesh, India. American Journal of Physical Anthropology 148:54–61.']
  • ['Gettler, Lee T. 2010. Direct male care and hominin evolution: why male-child interaction is more than a nice social idea. American Anthropologist 112:7–21.']
  • ['Godfrey, Laurie R., Karen E. Samonds, William L. Jungers, and Michael R. Sutherland. 2003. Dental development and primate life histories. In Primate life histories and socioecology. Peter M. Kappeler and Michael E. Pereira, eds. Pp. 177–203. Chicago: University of Chicago Press.']
  • ['Graves, Ronda R., Amy C. Lupo, Robert C. McCarthy, Daniel J. Wescott, and Deborah L. Cunningham. 2010. Just how strapping was KNM-WT 15000? Journal of Human Evolution 59:542–554.']
  • ['Guatelli-Steinberg, Debbie. 2009. Recent studies of dental development in Neandertals: implications for Neandertal life histories. Evolutionary Anthropology 18:9–20.']
  • ['Gurven, Michael, and Kim Hill. 2009. Why do men hunt? a reevaluation of “man the hunter” and the sexual division of labor. Current Anthropology 5:51–74.']
  • ['Haile-Selassie, Yohannes, Bruce M. Latimer, Mulugeta Alene, Alan L. Deino, Luis Gibert, Stephanie M. Melillo, Beverly Z. Saylor, Gary R. Scott, and C. Owen Lovejoy. 2010. An early Australopithecus afarensis postcranium from Woranso-Mille, Ethiopia. Proceedings of the National Academy of Sciences of the USA 107:12121–12126.']
  • ['Hill, Kim, and A. Magdalena Hurtado. 1996. Ache life history. New York: Aldine.']
  • ['———. 2009. Cooperative breeding in South American hunter-gatherers. Proceedings of the Royal Society B: Biological Sciences 276:3863–3870.']
  • ['Holliday, Trenton W. 2012. Body size, body shape, and the circumscription of the genus Homo. Current Anthropology 53(suppl. 6):S330–S345.']
  • ['Holliday, Trenton W., and Robert G. Franciscus. 2009. Body size and its consequences: allometry and the lower limb length of Liang Bua 1 (Homo floresiensis). Journal of Human Evolution 57:223–228.']
  • ['Holloway, Ralph L., and Michael S. Yuan. 2004. Endocranial morphology of A.L. 444-2. In The skull of Australopithecus afarensis. William H. Kimbel, Yoel Rak, and Donald C. Johanson, eds. Pp. 123–135. New York: Oxford University Press.']
  • ['Hrdy, Sarah B. 2009. Mothers and others: the evolutionary origins of mutual understanding. Cambridge, MA: Harvard University Press.']
  • ['Indriati, Etty, and Susan C. Antón. 2008. Earliest Indonesian facial and dental remains from Sangiran, Java: a description of Sangiran 27. Anthropological Science 116:219–229.']
  • ['Isler, Karin, and Carel P. van Schaik. 2009. The expensive brain: a framework for explaining evolutionary changes in brain size. Journal of Human Evolution 57:392–400.']
  • ['———. 2012. How our ancestors broke through the gray ceiling: comparative evidence for cooperative breeding in early Homo. Current Anthropology 53(suppl. 6):S453–S465.']
  • ['Jolly, Clifford J. 2001. A proper study for mankind: analogies from the papionin monkeys and their implications for human evolution. Yearbook of Physical Anthropology 44:177–204.']
  • ['Kaplan, Bernice A. 1954. Environment and human plasticity. American Anthropologist 56:780–800.']
  • ['Kaplan, Hillard S., Kim Hill, Jane Lancaster, and A. Magdalena Hurtado. 2000. A theory of human life history evolution: diet, intelligence, and longevity. Evolutionary Anthropology 9:156–183.']
  • ['Katzmarzyk, Peter T., and William R. Leonard. 1998. Climatic influences on human body size and proportions: ecological adaptations and secular trends. American Journal of Physical Anthropology 106:483–503.']
  • ['Key, Catherine, and Leslie C. Aiello. 2000. A prisoner’s dilemma model of the evolution of paternal care. Folia Primatologica (Basel) 71:77–92.']
  • ['Kramer, Karen L. 2010. Cooperative breeding and its significance to the demographic success of humans. Annual Review of Anthropology 39:417–436.']
  • ['Kuzawa, Christopher W. 1998. Adipose tissue in human infancy and childhood: an evolutionary perspective. Yearbook of Physical Anthropology 41:177–209.']
  • ['———. 2007. Developmental origins of life history: growth, productivity, and reproduction. American Journal of Human Biology 19:654–661.']
  • ['Kuzawa, Christopher W., and Jared M. Bragg. 2012. Plasticity in human life history strategy: implications for contemporary human variation and the evolution of genus Homo. Current Anthropology 53(suppl. 6):S369–S382.']
  • ['Kuzawa, Christopher W., Thomas W. McDade, Linda S. Adair, and Nanette Lee. 2010. Rapid weight gain after birth predicts life history and reproductive strategy in Filipino males. Proceedings of the National Academy of Sciences of the USA 107:16800–16805.']
  • ['Lancaster, Jane B., and Chet S. Lancaster. 1983. Parental investment: the hominid adaptation. In How humans adapt: a biocultural odyssey. Donald J. Ortner, ed. Pp. 33–69. Washington, DC: Smithsonian Institution.']
  • ['Lappan, Susan. 2009. The effects of lactation and infant care on the adult energy budgets in wild siamangs (Symphalangus syndactylus). American Journal of Physical Anthropology 140:290–301.']
  • ['Lasker, Gabriel W. 1969. Human biological adaptability. Science 166:1480–1486.']
  • ['Leakey, Louis S. B., Phillip V. Tobias, and John R. Napier. 1964. A new species of the genus Homo from Olduvai Gorge. Nature 202:7–9.']
  • ['Leakey, Meave G., Fred Spoor, M. Christopher Dean, Craig S. Feibel, Susan C. Antón, Christopher Kiarie, and Louise N. Leakey. 2012. New early Homo fossils from Koobi Fora, northern Kenya, highlight facial diversity. Nature 488:201–204.']
  • ['Leigh, Stephen R. 2001. Evolution of human growth. Evolutionary Anthropology 10:223–236.']
  • ['Leigh, Stephen R., and Gregory E. Blomquist. 2007. Life history. In Primates in perspective. Christina J. Campbell, Agustín Fuentes, Katherine C. MacKinnon, Melissa Panger, and Simon K. Bearder, eds. Pp. 396–407. New York: Oxford University Press.']
  • ['———. 2011. Life history. In Primates in perspective. 2nd edition. Christina J. Campbell, Agustín Fuentes, Katherine C. MacKinnon, Simon K. Bearder, and Rebecca M. Stumpf, eds. Pp. 418–428. New York: Oxford University Press.']
  • ['Leonard, William R., Marcia L. Robertson, J. Josh Snodgrass, and Christopher W. Kuzawa. 2003. Metabolic correlates of hominid brain expansion. Comparative Biochemistry and Physiology 136A:5–15.']
  • ['Lepre, Christopher J., Hélène Roche, Dennis V. Kent, Sonia Harmand, Rhonda L. Quinn, Jean-Philippe Brugal, Pierre-Jean Texier, Arnaud Lenoble, and Craig S. Feibel. 2011. An earlier origin for the Acheulian. Nature 477:82–85.']
  • ['Lockwood, Charles A., William H. Kimbel, and Donald C. Johanson. 2000. Temporal trends and metric variation in the mandibles and dentition of Australopithecus afarensis. Journal of Human Evolution 39:23–55.']
  • ['McPherron, Shannon P., Zeresenay Alemseged, Curtis W. Marean, Jonathan G. Wynn, Denné Reed, Denis Geraads, René Bobe, and Hamdallah A. Béarat. 2010. Evidence for stone-tool-assisted consumption of animal tissues before 3.39 million years ago at Dikika, Ethiopia. Nature 466:857–860.']
  • ['———. 2011. Tool-marked bones from before the Oldowan change the paradigm. Proceedings of the National Academy of Sciences of the USA 108(21):E116.']
  • ['Melis, Alicia P., and Dirk Semmann. 2010. How is human cooperation different? Philosophical Transactions of the Royal Society B: Biological Sciences 365:2663–2674.']
  • ['Migliano, Andrea Bamberg. 2005. Why pygmies are small: ontogenetic implications of life history evolution. PhD dissertation, University of Cambridge.']
  • ['Migliano, Andrea Bamberg, and Myrtille Guillon. 2012. The effects of mortality, subsistence, and ecology on human adult height and implications for Homo evolution. Current Anthropology 53(suppl. 6):S359–S368.']
  • ['Migliano, Andrea Bamberg, Lucio Vinicius, and Marta Mirazón Lahr. 2007. Life history trade-offs explain the evolution of human pygmies. Proceedings of the National Academy of Sciences of the USA 104:20216–20219.']
  • ['Mitani, John C., and David Watts. 1997. The evolution of non-maternal caretaking among anthropoid primates: do helpers help? Behavioral Ecology and Sociobiology 40:213–220.']
  • ['Muchlinski, Magdalena N., J. Josh Snodgrass, and Carl J. Terranova. 2012. Muscle mass scaling in primates: an energetic and ecological perspective. American Journal of Primatology 74:395–407.']
  • ['Pfeiffer, Susan. 2012. Conditions for evolution of small adult body size in southern Africa. Current Anthropology 53(suppl. 6):S383–S394.']
  • ['Plavcan, J. Michael. 2012. Body size, size variation, and sexual size dimorphism in early Homo. Current Anthropology 53(suppl. 6):S409–S423.']
  • ['Pond, Caroline M. 1998. The fats of life. Cambridge: Cambridge University Press.']
  • ['Pontzer, Herman. 2012. Ecological energetics in early Homo. Current Anthropology 53(suppl. 6):S346–S358.']
  • ['Pontzer, Herman, and Jason M. Kamilar. 2009. Great ranging associated with greater reproductive investment in mammals. Proceedings of the National Academy of Sciences of the USA 106(1):192–196.']
  • ['Pontzer, Herman, David A. Raichlen, Robert W. Shumaker, Cara Ocobock, and Serge A. Wich. 2010. Metabolic adaptation for low energy throughput in orangutans. Proceedings of the National Academy of Sciences of the USA 107(32):14048–14052.']
  • ['Potts, Richard. 2012. Environmental and behavioral evidence pertaining to the evolution of early Homo. Current Anthropology 53(suppl. 6):S299–S317.']
  • ['Potts, Richard, Anna K. Behrensmeyer, Alan Deino, Peter Ditchfield, and Jennifer Clark. 2004. Small mid-Pleistocene hominin associated with East African Acheulean technology. Science 305:75–78.']
  • ['Roberts, Derek F. 1978. Climate and human variability. 2nd edition. Menlo Park, CA: Cummings.']
  • ['Robson, Shannen L., and Bernard Wood. 2008. Hominin life history: reconstruction and evolution. Journal of Anatomy 212:394–425.']
  • ['Roche, Hélène, Robert J. Blumenschine, and John J. Shea. 2009. Origins and adaptations of early Homo: what archaeology tells us. In The first humans: origin and early evolution of the genus Homo. Fred E. Grine, John G. Fleagle, and Richard E. Leakey, eds. Pp. 197–207. New York: Springer.']
  • ['Ross, Caroline, and Ann MacLarnon. 2000. The evolution of non-maternal care in anthropoid primates: a test of the hypotheses. Folia Primatologica 71:93–113.']
  • ['Ruff, Christopher B. 2008. Femoral/humeral strength in early African Homo erectus. Journal of Human Evolution 54:383–390.']
  • ['———. 2009. Relative limb strength and locomotion in Homo habilis. American Journal of Physical Anthropology 138:90–100.']
  • ['———. 2010. Body size and body shape in early hominins: implications of the Gona pelvis. Journal of Human Evolution 58:166–178.']
  • ['Schmidt-Nielsen, Knut. 1984. Scaling: why is animal size so important? Cambridge: Cambridge University Press.']
  • ['Schoenemann, P. Thomas. 2006. Evolution of the size and functional areas of the human brain. Annual Review of Anthropology 35:379–406.']
  • ['Schroepfer, Kara K., Brian Hare, and Herman Pontzer. 2012. Energy expenditure in semi free-ranging chimpanzees measured using doubly labeled water. American Journal of Physical Anthropology 147(suppl. 54):263.']
  • ['Schwartz, Gary T. 2012. Growth, development, and life history throughout the evolution of Homo. Current Anthropology 53(suppl. 6):S395–S408.']
  • ['Sellen, Daniel W. 2001. Comparison of infant feeding patterns reported for nonindustrial populations with current recommendations. Journal of Nutrition 131:2707–2715.']
  • ['Semaw, Sileshi, Michael J. Rogers, Jay Quade, Paul R. Renne, Robert F. Butler, Dietrich Stout, Manuel Dominguez-Rodrigo, William Hart, Travis Pickering, and Scott Simpson. 2003. 2.6-million-year-old stone tools and associated bones from OGS-6 and OGS-7, Gona, Afar, Ethiopia. Journal of Human Evolution 45:169–177.']
  • ['Šešelj, Maja. 2011. Human growth evolving: integrating dental and skeletal growth proxies to understand ontogeny in Pleistocene Homo. PhD dissertation, New York University.']
  • ['Shapiro, Harry L. 1939. Migration and environment: a study of the physical characteristics of the Japanese immigrants to Hawaii and the effects of environment on their descendants. London: Oxford University Press.']
  • ['Shipman, Pat, and Alan Walker. 1989. The costs of becoming a predator. Journal of Human Evolution 18:373–392.']
  • ['Simpson, Scott W., Jay Quade, Naomi E. Levin, Robert Butler, Guillaume Dupont-Nivet, Melanie Everett, and Sileshi Semaw. 2008. A female Homo erectus pelvis from Gona, Ethiopia. Science 322:1089–1092.']
  • ['Smith, Jennifer E., Eli M. Swanson, Daphna Reed, and Kay E. Holekamp. 2012. Evolution of cooperation among mammalian carnivores and its relevance to hominin evolution. Current Anthropology 53(suppl. 6):S436–S452.']
  • ['Snodgrass, J. Josh. 2012. Human energetics. In Human biology: an evolutionary and biocultural approach. 2nd edition. Sara Stinson, Barry Bogin, and Dennis O’Rourke, eds. Pp. 327–386. New York: Wiley.']
  • ['Snodgrass, J. Josh, William R. Leonard, and Marcia L. Robertson. 2009. The energetics of encephalization in early hominids. In Evolution of hominid diets: integrating approaches to the study of Palaeolithic subsistence. Jean-Jacques Hublin and Michael Richards, eds. Pp. 15–29. Dordrecht: Springer.']
  • ['Spoor, Fred, Meave G. Leakey, Patrick N. Gathogo, Frank H. Brown, Susan C. Antón, Ian McDougall, Christopher Kiarie, Frederick K. Manthi, and Louise N. Leakey. 2007. Implications of new early Homo fossils from Ileret, east of Lake Turkana, Kenya. Nature 448:688–691.']
  • ['Stahl, Walter R. 1965. Organ weights in primates and other mammals. Science 150:1039–1042.']
  • ['Stearns, Stephen C. 1992. The evolution of life histories. Oxford: Oxford University Press.']
  • ['Stini, William A. 1972. Reduced sexual dimorphism in upper arm muscle circumference associated with a protein-deficient diet in a South American population. American Journal of Physical Anthropology 36:341–352.']
  • ['———. 1975. Adaptive strategies of human populations under nutritional stress. In Biosocial interrelations in population adaptation. Elizabeth S. Watts, Frances E. Johnson, and Gabriel W. Lasker, eds. Pp. 19–41. The Hague: Mouton.']
  • ['Stinson, Sara. 1985. Sex differences in environmental sensitivity during growth and development. Yearbook of Physical Anthropology 28:125–147.']
  • ['———. 2012. Growth variation: biological and cultural factors. In Human biology: an evolutionary and biocultural approach. 2nd edition. Sara Stinson, Barry Bogin, and Dennis O’Rourke, eds. Pp. 587–635. New York: Wiley.']
  • ['Swedell, Larissa, and Thomas Plummer. 2012. A papionin multilevel society as a model for hominin social evolution. International Journal of Primatology, doi:10.1007/s10764-012-9600-9.']
  • ['Swisher, Carl C., III, Garniss H. Curtis, Teuku Jacob, Ann G. Getty, Agus Suprijo, and Widiasmoro. 1994. Age of the earliest known hominids in Java, Indonesia. Science 263:1118–1121.']
  • ['Thompson, Jennifer L., and Andrew J. Nelson. 2011. Middle childhood and modern human origins. Human Nature 22:249–280.']
  • ['Trevathan, Wenda R. 1987. Human birth: an evolutionary perspective. Hawthorne, NY: Aldine de Gruyter.']
  • ['Ungar, Peter S. 2012. Dental evidence for the reconstruction of diet in African early Homo. Current Anthropology 53(suppl. 6):S318–S329.']
  • ['Ungar, Peter S., Kristin L. Krueger, Robert J. Blumenschine, Jackson Njau, and Robert S. Scott. 2012. Dental microwear texture analysis of hominins recovered by the Olduvai Landscape Paleoanthropology Project, 1995–2007. Journal of Human Evolution 63:429–437.']
  • ['Ungar, Peter S., and Robert S. Scott. 2009. Dental evidence for diets of early Homo. In The first humans: origin and early evolution of the genus Homo. Fred E. Grine, John G. Fleagle, and Richard E. Leakey, eds. Pp. 121–134. New York: Springer.']
  • ['Ungar, Peter S., and Matt Sponheimer. 2011. The diets of early hominins. Science 334:190–193.']
  • ['Valeggia, Claudia R., and Peter T. Ellison. 2001. Lactation, energetics and postpartum fecundity. In Reproductive ecology and human evolution. Peter T. Ellison, ed. Pp. 85–105. New York: Aldine.']
  • ['Walker, Robert, Michael Gurven, Kim Hill, Andrea Migliano, Napolean Chagnon, Roberta De Souza, Gradimir Djurovic, et al. 2006. Growth rates and life histories in twenty-two small-scale societies. American Journal of Human Biology 18:295–311.']
  • ['Wells, Jonathan C. K. 2006. The evolution of human fatness and susceptibility to obesity: an ethological approach. Biological Reviews 81:183–205.']
  • ['———. 2010. The evolutionary biology of human body fatness: thrift and control. Cambridge: Cambridge University Press.']
  • ['———. 2012. The capital economy in hominin evolution: how adipose tissue and social relationships confer phenotypic flexibility and resilience in stochastic environments. Current Anthropology 53(suppl. 6):S466–S478.']
  • ['Wood, Bernard, and Mark Collard. 1999. The human genus. Science 284:65–71.']