Evolution of Human Lactation and Complementary Feeding: Implications for Understanding Contemporary Cross-cultural Variation

  • D. W. Sellen
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 639)

Artistic reconstructions of ancestral hominids1 often depict mothers with bared breasts and suckling infants, reflecting assumptions about the importance of lactation in human evolution. However, anthropologists have published no detailed theories about how our ancestors fed young children. In the absence of a scientific model of the evolution of human lactation and complementary feeding, it is difficult to evaluate claims made about the long duration of ancient breast-feeding or the “naturalness” of lactation patterns observed in some human societies. This chapter therefore has two main goals. First, I review several lines of evidence that suggest how changes in birth spacing, foraging strategy and sociality may have increased the selective advantages of a more flexible pattern of lactation and a behavioural shift towards complementary feeding in past environments. Second, I develop a hypothesis that the complementary feeding of young children is a fundamental component of life and socio-behavioural adaptations that evolved among our human ancestors as an ecological strategy for increasing maternal fitness. I suggest that the ancestral habit of introducing safe complementary feeding after a period of exclusive breast-feeding is unique to humans. It is linked to the evolution of a species-typical care giving “package”, which includes social foraging, food sharing, food processing, and a capacity to invent technological solutions to dietary challenges. I conclude with a brief review of how changes in social organisation, time allocation and diet quality that accompanied the agricultural and industrial revolutions have created an environment in which the evolved tendency to introduce foods to breast-feeding young undermines the health of populations.

Keywords

Carbohydrate Lactate Marketing Cretaceous Carotenoid 

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References

  1. 1.
    Ford CS (1945) A comparative study of human reproduction, in: Yale University Publications in Anthropology, Yale University Press, New Haven.Google Scholar
  2. 2.
    Raphael D & Davis F (1985) Only mothers know: Patterns of infant feeding in traditional cultures. In: Contributions in Women’s Studies, Greenwood Press, prepared under the auspices of The Human Lactation Center, Ltd, Westport, CT.Google Scholar
  3. 3.
    Winikoff B, Castle MA, Laukaran VH (1988) Feeding infants in four societies: Causes and consequences of mothers’ choices. In: Contributions in Family Studies, Greenwood Press, New York.Google Scholar
  4. 4.
    Maher V (1992) The anthropology of breast-feeding: Natural law or social contract. In: Cross-Cultural Perspectives on Women, Berg, Oxford University Press/Providence, pp. 185.Google Scholar
  5. 5.
    DeLoache J & Gottlieb A (2000) A World of Babies: Imagined Childcare Guides for Seven Societies. Cambridge University Press, Cambridge.Google Scholar
  6. 6.
    Wickes IG (1953) A history of infant feeding. Part I. Primitive peoples: ancient works: Renaissance writers. Arch Dis Child 28:151–158.PubMedGoogle Scholar
  7. 7.
    Wickes IG (1953) A history of infant feeding. Part V. Nineteenth century concluded and twentieth century, Arch Dis Child 28:495–502.PubMedGoogle Scholar
  8. 8.
    Wickes IG (1953) A history of infant feeding. Part Ii. Seventeenth and eighteenth centuries. Arch Dis Child 28:232–240.PubMedGoogle Scholar
  9. 9.
    Wickes IG (1953) A history of infant feeding. Part Iii. Eighteenth and nineteenth century writers. Arch Dis Child 28:332–340.PubMedGoogle Scholar
  10. 10.
    Hrdy SB (1992) Fitness tradeoffs in the history and evolution of delegated mothering with special reference to wet-nursing, abandonment, and infanticide. Ethol Sociobiol 13:409–442.CrossRefGoogle Scholar
  11. 11.
    Whitaker ED (2000) Measuring mamma’s milk: Fascism and the medicalization of maternity in Italy. The University of Michigan Press, Ann Arbor.Google Scholar
  12. 12.
    WHO (1991) Indicators for Assessing Breast-Feeding Practices. Report of Informal Meeting 11–12 June 1991. WHO, Geneva.Google Scholar
  13. 13.
    Labbok M & Coffin C (1997) A call for consistency in definition of breast-feeding behaviors. Soc Sci Med 44:1931–32.PubMedCrossRefGoogle Scholar
  14. 14.
    Ruel MT, Brown KH, Caulfield LE (2003) Moving forward with complementary feeding: Indicators and research priorities. Food Nutr Bull 24:289–290.PubMedGoogle Scholar
  15. 15.
    WHO (2001) Global strategy for infant and young child feeding: The optimal duration of exclusive breastfeeding. World Health Organization, Geneva, pp. 1–5.Google Scholar
  16. 16.
    Kramer MS & Kakuma R (2002) The optimal duration of exclusive breastfeeding: A systematic review. World Health Organization, Geneva, pp. 47.Google Scholar
  17. 17.
    Gibson R, Ferguson E, Lehrfeld J (1998) Complementary foods for infant feeding in developing countries: Their nutrient adequacy and improvement. Eur J Clin Nutr 52:764–770.PubMedCrossRefGoogle Scholar
  18. 18.
    Michaelsen KF & Friis H (1998) Complementary feeding: A global perspective. Nutrition 14:763–766.PubMedCrossRefGoogle Scholar
  19. 19.
    Hotz C & Gibson RS (2001) Complementary feeding practices and dietary intakes from complementary foods amongst weanlings in rural Malawi. Eur J Clin Nutr 55:841–849.PubMedCrossRefGoogle Scholar
  20. 20.
    WHO (2004) The Importance of Caregiver-Child Interactions for the Survival and Healthy Development of Young Children: A Review, World Health Organization, Geneva.Google Scholar
  21. 21.
    WHO (1979) Joint WHO/UNICEF Meeting on Infant and Young Child Feeding. Statement and Recommendations. World Health Organisation, Geneva.Google Scholar
  22. 22.
    Brown KH, Dewey KG, Allen L (1998) Complementary feeding of young children in developing countries: A review of current scientific knowledge. World Health Organisation, Geneva, pp. 178.Google Scholar
  23. 23.
    Dewey K (2003) Guiding principles for complementary feeding of the breastfed child. World Health Organization, Geneva.Google Scholar
  24. 24.
    Allen LH & Pelto GH (1985) Research on determinants of breast-feeding duration: Suggestions for biocultural studies. Med Anthropol 9:97–106.PubMedGoogle Scholar
  25. 25.
    Van Esterik P (1995) The politics of breastfeeding: An advocacy approach. In: Breastfeeding: biocultural perspectives (P Stuart-Macadam, and KA Dettwyler, eds.), Aldine de Gruyter, New York, pp. 145–165.Google Scholar
  26. 26.
    Pelto G, Levitt E, Thairu L (2003) Improving feeding practices: Current patterns, common constraints, and the design of interventions. Food Nut Bull 24:45–82.Google Scholar
  27. 27.
    Darwin C (1964 [1872]) On the Origin of Species. Harvard University Press, Cambridge, MA.Google Scholar
  28. 28.
    Rowe T (1988) Definition, diagnosis, and origin of Mammalia. J Vertebrate Paleontol 8:241–264.Google Scholar
  29. 29.
    Jenness R (1974) Biosynthesis and composition of milk. J Invest Dermatol 63:109–118.PubMedCrossRefGoogle Scholar
  30. 30.
    Kumar S & Hedges B (1998) A molecular timescale for vertebrate evolution, Nature 392:917–920.PubMedCrossRefGoogle Scholar
  31. 31.
    Messer M, Weiss AS, Shaw DC, Westerman M (1998) Evolution of the monotremes: Phylogenetic relationship to marsupials and eutherians, and estimation of divergence dates based on a-lactalbumin amino acid sequences. J Mammalian Evol 5:95–105.CrossRefGoogle Scholar
  32. 32.
    Woodburne MO, Rich TH, Springer MS (2003) The evolution of tribospheny and the antiquity of mammalian clades. Molec Phylogenet Evol 28:360–385.PubMedCrossRefGoogle Scholar
  33. 33.
    Kermack KA, Mussett F, Rigney HW (1981) The skull of Morganucodon. Zoological J Linnean Soc 71:1–158.CrossRefGoogle Scholar
  34. 34.
    Luo ZX, Crompton AW, Sun AL (2002) A new Mammaliaform from the early Jurassic and evolution of mammalian characteristics. Science 292:1535–1540.CrossRefGoogle Scholar
  35. 35.
    Cifelli RL, Rowe TB, Luckett WP, Banta J, Reyes R, Howes RI (1996) Fossil evidence for the origin of the marsupial pattern of tooth replacement. Nature 379:715–718.CrossRefGoogle Scholar
  36. 36.
    Hayssen VD & Blackburn DG (1985) Alpha-lactalbumin and the evolution of lactation. Evol 39:1147–1149.CrossRefGoogle Scholar
  37. 37.
    Goldman AS, Chheda S, Garofalo R (1998) Evolution of immunologic functions of the mammary gland and the postnatal development of immunity. Pediatric Res 43:155–162.CrossRefGoogle Scholar
  38. 38.
    Blackburn DG (1985) The evolution of viviparity and matrotrophy in vertebrates, with special reference to reptiles. Cornell.Google Scholar
  39. 39.
    Pond CM (1977) The significance of lactation in the evolution of mammals. Evol 31:177–199.CrossRefGoogle Scholar
  40. 40.
    Blackburn DG, Hayssen V, Murphy CJ (1989) The origins of lactation and the evolution of milk: A review with hypothesis. Mammal Review 19:1–26.CrossRefGoogle Scholar
  41. 41.
    Bronson FH (1985) Mammalian reproduction: An ecological perspective. Biol Reprod 32:1–26.PubMedCrossRefGoogle Scholar
  42. 42.
    Hartmann PE, Rattigan S, Presser CG, Saint L, Arthur PG (1984) Human lactation: Back to nature. Symp Zool Soc Lond 51:337–368.Google Scholar
  43. 43.
    Fleet IR, Goode JA, Hamon MH, Laurie MS, Linzell JL, Peaker M (1975) Secretory activity of goat mammary glands during pregnancy and the onset of lactation. J Physiol 251:763–773.PubMedGoogle Scholar
  44. 44.
    Hartmann PE (1973) Changes in the composition and yield of the mammary secretion of cows during the initiation of lactation Endocrinol 59:231–247.Google Scholar
  45. 45.
    Hayssen V (1993) Empirical and theoretical constraints on the evolution of lactation. J Dairy Sci 76:3213–3233.PubMedCrossRefGoogle Scholar
  46. 46.
    Ben Shaul DM (1962) The composition of the milk of wild animals. Int Zoological Yearbook 4:333–342.CrossRefGoogle Scholar
  47. 47.
    Oftedal OT (1984) Milk composition, milk yield and energy output at peak lactation: A comparative review. Symp Zool Soc Lond 51:33–85.Google Scholar
  48. 48.
    Blaxter KL (1961) Lactation and growth of the young. In: Milk: The mammary gland and its secretion (SK Kon, AT Cowie, eds.), Academic Press, London, pp. 305–361.Google Scholar
  49. 49.
    Oftedal OT (1984) Body size and reproductive strategy as correlates of milk energy output in lactating mammals. Acta zoologica Fennica 171:183–186.Google Scholar
  50. 50.
    Lee PC (1997) The meaning of weaning: growth, lactation, and life history. Evol Anthropol 5:87–96.CrossRefGoogle Scholar
  51. 51.
    Lee PC (1999) Comparative ecology of postnatal growth and weaning among Haplorhine primates. In: Comparative Primate Socioecology (PC Lee, ed), Cambridge University Press, Cambridge, pp. 111–139.Google Scholar
  52. 52.
    Harvey PH & Clutton-Brock TH (1985) Life history variation in primates. Evol 39:559–581.CrossRefGoogle Scholar
  53. 53.
    Smith BH (1991) Dental development and the evolution of life history in the Hominidae. Am J Phys Anthropol 86:157–174.CrossRefGoogle Scholar
  54. 54.
    Smith BH (1992) Life history and the evolution of human maturation, Evol Anthropol. 1:134–142.CrossRefGoogle Scholar
  55. 55.
    Lee PC, Majluf P, Gordon IJ (1991) Growth, weaning and maternal investment from a comparative perspective. J Zoology 225:99–114.Google Scholar
  56. 56.
    Charnov EL & Berrigan D (1993) Why do female primates have such long lifespans and so few babies? Or life in the slow lane, Evol Anthropol 1:191–194.CrossRefGoogle Scholar
  57. 57.
    Seilen DW, Robson S, Hawkes K. Transitional feeding in nonhuman primates. Unpublished MS, Department of Anthropology, University of Toronto.Google Scholar
  58. 58.
    Kanazawa AT, Miyazawa T, Hirono H, Hayashi M, Fujimoto K (1991) Possible essentiality of docosahexaenoic acid in Japanese monkey neonates: Occurrence in colostrum and low biosynthetic capacity in neonate brains. Lipids 26:53–57.PubMedCrossRefGoogle Scholar
  59. 59.
    Patino EM & Borda JT (1997) The composition of primate’s milks and its importance in selecting formulas for hand rearing. Laboratory Primate Newsletter 36:8–9.Google Scholar
  60. 60.
    National Research Council of the National Academies of Science (2003) Nutrient requirements of nonhuman primates, table 9-4. The National Academies Press, Washington, DC, pp. 1–286.Google Scholar
  61. 61.
    Robson SL (2004) Breast milk, diet, and large human brains. Curr Anthropol 45:419–424.CrossRefGoogle Scholar
  62. 62.
    Seilen DW (in press) Lactation, complementary feeding and human life history. In: The Evolution of Human Life History (RL Paine, K Hawkes, eds), School of American Research Press, Santa Fe, NM.Google Scholar
  63. 63.
    Lee PC & Bowman JE (1995) Influence of ecology and energetics on primate mothers and infants. In: Motherhood in Human and Nonhuman Primates (CR Pryce, RD Martin, D Skuse, eds), Karger, New York.Google Scholar
  64. 64.
    Martin RD (1984) Scaling effects and adaptive strategies in mammalian lactation. Symp Zool Soc Lond 51:87–117.Google Scholar
  65. 65.
    Buss DH (1971) Mammary glands and lactation. In: Comparative Reproduction of Nonhuman Primates (ESE Hafez, ed), Charles C Thomas, Springfield, Illinois.Google Scholar
  66. 66.
    Low B (1990) Fat and deception. Ethol Sociobiol 11:67–74.CrossRefGoogle Scholar
  67. 67.
    Marlowe F (1999) The Nubility Hypothesis: The human breast as an honest signal of residual reproductive value. Hum Nat 9:263–271.CrossRefGoogle Scholar
  68. 68.
    Laurence DJ, Monanghan P, Gusterson BA (1991) The development of the normal human breast. Oxf Rev Reprod Biol 13:149–174.PubMedGoogle Scholar
  69. 69.
    Altmann J, Altmann SA, Hausfater G (1978) Primate infant’s effects on mother’s future reproduction. Science 201:1028–1030.PubMedCrossRefGoogle Scholar
  70. 70.
    Altmann J & Samuels A (1992) Costs of maternal care: Infant carrying in baboons. Behav Eco Sociobiol 29:391–398.Google Scholar
  71. 71.
    Dufour DL & Sauther ML (2002) Comparative and evolutionary dimensions of the energetics of human pregnancy and lactation. Am J Hum Biol 14:584–602.PubMedCrossRefGoogle Scholar
  72. 72.
    Harcourt A (1987) Dominance and fertility among female primates. J Zool (Lond) 213:471–487.CrossRefGoogle Scholar
  73. 73.
    Lee P (1987) Nutrition, fertility and maternal investment in primates. J Zool (Lond) 213:409–422.Google Scholar
  74. 74.
    Boinski S (1988) Sex differences in the foraging behavior of Squirrel Monkeys in a seasonal habitat. Behav Ecol Sociobiol 32:177–186.CrossRefGoogle Scholar
  75. 75.
    Sauther ML (1994) Changes in the use of wild plant foods in free-ranging ring-tailed lemurs during pregnancy and lactation: Some implications for human foraging strategies. In: Eating on the wild side: The pharmacologic, ecologic and social implications of using non-cultigens (NL Etkin, ed), University of Arizona Press, Tucson, pp. 240–246.Google Scholar
  76. 76.
    Stacey PB (1986) Group size and foraging efficiency in yellow baboons. Behav Ecol Sociobiol 18:175–187.CrossRefGoogle Scholar
  77. 77.
    Altmann J (1980) Baboon mothers and infants. Harvard University Press, Cambridge, MA.Google Scholar
  78. 78.
    Dunbar RIM & Dunbar P (1988) Maternal time budgets of Gelada baboons. Anim Behav 36:970–980.CrossRefGoogle Scholar
  79. 79.
    Dunbar RTM, Hannah-Stewart L, Dunbar P (2002) Forage quality and the costs of lactation for female Gelada baboons. Animal Behav 64:801–805.CrossRefGoogle Scholar
  80. 80.
    Bercovitch FB (1987) Female weight and reproductive condition in a population of Olive baboons (Papio Anubis). Am J Primat 12:189–195.CrossRefGoogle Scholar
  81. 81.
    Roberts SB, Cole TJ, Coward WA (1985) Lactational performance in relation to energy intake in the baboon. Am J Clin Nutr 41:1270–1276.PubMedGoogle Scholar
  82. 82.
    Harrison MJS (1983) Age and sex differences in the diet and feeding strategies of the Green Monkey. Cercopithecus Sabaeus. Anim Behav 31:969–977.CrossRefGoogle Scholar
  83. 83.
    Tardif SD, Harrison ML, Simek MA (1993) Communal infant care in marmosets and tamarins: Relation to energetics, ecology, and social organization. In: Marmosets and tamarins: systematics, behaviour, and ecology (AB Rylands, ed), Oxford University Press, New York.Google Scholar
  84. 84.
    Prentice AM, Spaaij CJ, Goldberg GR et al (1996) Energy requirements of pregnant and lactating women. Eur J Clin Nutr 50(Suppl. 1): S82–S111.PubMedGoogle Scholar
  85. 85.
    Durnin JVGA (1987) Energy requirements of pregnancy: An integration of the longitudinal data from the Five-Country Study. Lancet 2:1131.PubMedCrossRefGoogle Scholar
  86. 86.
    Lawrence M, Coward W, Lawrence F, Cole T, Whitehead R (1987) Fat gain during pregnancy in rural African women: The effect of season and dietary status. Am J Clin Nutr 45:1442–14450.PubMedGoogle Scholar
  87. 87.
    Prentice AM & Goldberg GR (2000) Energy adaptations in human pregnancy: Limits and long-term consequences. Am J Clin Nutr 71(5 Suppl):1226S–1232S.PubMedGoogle Scholar
  88. 88.
    Leutenegger W (1973) Maternal-fetal weight relationship in primates. Folia Primate 20:280–293.CrossRefGoogle Scholar
  89. 89.
    Kuzawa CW (1998) Adipose tissue in human infancy and childhood: An evolutionary perspective. Yrbk Phys Anthropol 41:177–209.CrossRefGoogle Scholar
  90. 90.
    Bogin B (1999) Evolutionary perspective on human growth. Ann Rev Anthropol 28:109–153.CrossRefGoogle Scholar
  91. 91.
    Hawkes K (in press) Life history and the evolution of the human lineage: Some ideas and findings. In: The evolution of human life histories (K Hawkes, RL Paine, eds), School of American Research Press, Santa Fe, New Mexico.Google Scholar
  92. 92.
    Butte NF (1996) Energy requirements of infants. Eur J Clin Nutr 50:S24–S36.PubMedGoogle Scholar
  93. 93.
    Butte NF, Wong WW, Hopkinson JM, Heinz CJ, Mehta NR, Smith, EOB (2000) Energy requirements derived from total energy expenditure and energy deposition during the first 2 y of life. Am J Clin Nutr 72:1558–1569.PubMedGoogle Scholar
  94. 94.
    Altmann SA (1998) Appendix 1. Primate nutrient requirements and toxin limits. In: Foraging for survival: yearling baboons in Africa, Chicago University Press, Chicago, pp. 373–393.Google Scholar
  95. 95.
    National Academy of Sciences (1978) Nutritional requirements of nonhuman primates, National Academy Press, Washington, DC, pp. 1–14.Google Scholar
  96. 96.
    Nicolosi RJ, Hunt RD (1979) Dietary allowances for nutrients in nonhuman primates. In: Primates in nutritional research (KC Hayes, ed), Academic Press, New York, pp. 11–37.Google Scholar
  97. 97.
    Altmann SA (1998) Foraging for survival: yearling baboons in Africa, Chicago University Press, Chicago, pp. 609.Google Scholar
  98. 98.
    Heinig MJ (2001) Host defense benefits of breastfeeding for the infant. Effect of breastfeeding duration and exclusivity. Ped Clinics N Amer 48:105–123.CrossRefGoogle Scholar
  99. 99.
    Blurton Jones N, Hawkes K, O’Connell JF (1999) Some current ideas about the evolution of the human life history. In: Comparative primate socioecology (PC Lee, ed), Cambridge University Press, Cambridge, pp. 140–166.Google Scholar
  100. 100.
    Galdikas BMF & Wood JW (1990) Birth spacing patterns in humans and apes. Am J Phys Anthropol 83:185–191.PubMedCrossRefGoogle Scholar
  101. 101.
    Hill K & Hurtado M (1996) Ache life history: The ecology and demography of a foraging people. In: Foundations of Human Behavior, Aldine de Gruyter, Hawthorne, NY.Google Scholar
  102. 102.
    WHO Collaborative Study Team on the Role of Breastfeeding on the Prevention of Infant Mortality (2000) Effect of breastfeeding on infant and child mortality due to infectious diseases in less developed countries: A pooled analysis. Lancet 355:451–455.Google Scholar
  103. 103.
    Shahidullah M (1994) Breast-feeding and child survival in Matlab, Bangladesh. J. Biosoc Sci 26:143–154.PubMedCrossRefGoogle Scholar
  104. 104.
    Manda SOM (1999) Birth intervals, breastfeeding and determinants of childhood mortality in Malawi. Soc Sci Med 48:301–312.PubMedCrossRefGoogle Scholar
  105. 105.
    Hewlett B (1991) Demography and childcare in preindustrial societies. J Anthropol Res 47:1–37.PubMedGoogle Scholar
  106. 106.
    Kaplan H, Hill K, Hurtado AM, Lancaster J (2001) The embodied capital theory of human evolution. In: Reproductive ecology and human evolution (PT Ellison, ed), Aldine de Gruyter, New York, pp. 293–317.Google Scholar
  107. 107.
    Seilen DW & Mace R (1999) A phylogenetic analysis of the relationship between sub-adult mortality and mode of subsistence. J Biosoc Sci 31:1–16.CrossRefGoogle Scholar
  108. 108.
    Nishida T, Corp N, Hamai M. et al (2003) Demography, female life history, and reproductive profiles among the chimpanzees of Mahale. Am J Primat 59:99–121.CrossRefGoogle Scholar
  109. 109.
    Hartmann P & Arthur P (1986) Assessment of lactation performance in women. In: Human lactation 2: Maternal and environmental factors (M Hamosh, A Goldman, eds), Plenum Press, New York, pp. 215–230.Google Scholar
  110. 110.
    Blurton Jones N (1993) The lives of hunter-gatherer children: Effects of parental behavior and parental reproductive strategy. In: Juvenile primates: Life history, development, and behavior (ME Pereira, LA Fairbanks, eds), Oxford University Press, New York.Google Scholar
  111. 111.
    Caro TM & Seilen DW (1990) On the reproductive advantages of fat in women. Ethol Sociobiol 11:51–66.CrossRefGoogle Scholar
  112. 112.
    Ellison PT (1994) Advances in human reproductive ecology. Ann Rev Anthropol 23:255–275.CrossRefGoogle Scholar
  113. 113.
    Hrdy S (1999) Mother nature: A history of mothers, infants and natural selection, Random House, New York, pp. 944.Google Scholar
  114. 114.
    McDade TW & Worthman CM (1998) The weanling’s dilemma reconsidered: A biocultural analysis of breastfeeding ecology. J Devel Behav Ped 19:286–299.Google Scholar
  115. 115.
    Baumslag N & Michels DL (1995) Milk, money, and madness: The culture and politics of breastfeeding, Bergin & Garvey, Westport, London, pp. 256.Google Scholar
  116. 116.
    Seilen DW (2001) Weaning, complementary feeding, and maternal decision making in a rural East African pastoral population. J Hum Lact 17:233–244.CrossRefGoogle Scholar
  117. 117.
    Hawkes K (in press) Slow life histories and human evolution. In: The evolution of human life histories (K Hawkes, RL Paine, eds), School of American Research Press, Santa Fe, New Mexico.Google Scholar
  118. 118.
    Charnov EL (1991) Evolution of life history variation among female mammals. Proc Natl Acad Sci USA 88:1134–1137.PubMedCrossRefGoogle Scholar
  119. 119.
    Charnov EL (1993) Life history invariants, Oxford University Press, Oxford, pp. 191–194.Google Scholar
  120. 120.
    Charnov EL (2001) Evolution of mammal life histories. Evolut Ecol Res 3:521–535.Google Scholar
  121. 121.
    Janson CH & Van Schaik CP (1993) Ecological risk aversion in juvenile primates: Slow and steady wins the race. In: Juvenile primates: Life history, development and behavior (ME Pereira, LA Fairbanks, eds), Oxford University Press, New York.Google Scholar
  122. 122.
    Bird DW (2001) Human foraging strategies: Human diet and food practices. In: Encyclopedia of evolution (M Pagel, ed), Oxford University Press.Google Scholar
  123. 123.
    Wrangham R, Jones JH, Laden G, Pilbeam D, Conklin-Brittain N (1999) The raw and the stolen: Cooking and the ecology of human origins. Curr Anthropol 40:567–594.PubMedCrossRefGoogle Scholar
  124. 124.
    Conklin-Brittain N, Wrangham R, Smith CC (2002) A two-stage model of increased dietary quality in early hominid evolution: The role of fiber. In: Human diet: Perspectives on its origin and evolution (PS Ungar, MF.Teaford eds), Greenwood Publishing Group.Google Scholar
  125. 125.
    Trevathan WR & McKenna JJ (1994) Evolutionary environments of human birth and infancy: Insights to apply to contemporary life. Children’s Environments 11:88–104.Google Scholar
  126. 126.
    Brown K, Dewey K, Allen L (1998) Complementary feeding of young children in developing countries: A review of current scientific knowledge. World Health Organization, Geneva.Google Scholar
  127. 127.
    WHO (2001) The optimal duration of exclusive breastfeeding. World Health Organization, Geneva.Google Scholar
  128. 128.
    Seilen D (2001) Comparison of infant feeding patterns reported for nonindustrial populations with current recommendations. J Nutr 131:2707–2715.Google Scholar
  129. 129.
    Seilen DW & Smay DB (2001) Relationship between subsistence and age at weaning in “pre-industrial societies”. Hum Nature Interdiscip J 12:47–87.CrossRefGoogle Scholar
  130. 130.
    Cohen MN, Armelagos GJ (1984) Paleopathology at the origins of agriculture, Academic Press, New York.Google Scholar
  131. 131.
    Larson C (1995) Biological changes in human populations with agriculture. Ann Rev Anthropol 24:185–213.CrossRefGoogle Scholar
  132. 132.
    Nerlove SB (1974) Women’s workload and infant feeding practices: A relationship with demographic implications Ethnol 13:207–214.CrossRefGoogle Scholar
  133. 133.
    Lutter CK (2000) Breastfeeding promotion: Is its effectiveness supported by scientific evidence and global changes in breastfeeding behaviors? In: Short and long term effects of breastfeeding on infant health (B Koletzo, O Hernell, K Michaelson, eds), Plenum Press, New York.Google Scholar
  134. 134.
    Seilen DW (2001) Of what use is an evolutionary anthropology of weaning? Hum Nature Interdiscip J 12:1–7.CrossRefGoogle Scholar
  135. 135.
    Moffat T (2001) A biocultural investigation of the weanling’s dilemma in Kathmandu, Nepal: Do universal recommendations for weaning practices make sense? J Biosoc Sci 33:321–338.PubMedCrossRefGoogle Scholar
  136. 136.
    Panter-Brick C (1992) Women’s working behaviour and maternal-child health in Rural Nepal. In: Physical activity and health (N Norgan, ed), Cambridge University Press, Cambridge, pp. 190–206.Google Scholar
  137. 137.
    Marriot H (1997) Juggling time and dropping the baby?: Constraints faced by Malian women. In: Population dynamics: Some past and emerging issues (R Powell, E Mwafeni, A Ankomah, eds), University of Exeter, Exeter, pp. 74–83.Google Scholar
  138. 138.
    Hausman BL (2000) Rational management: Medical authority and ideological conflict in Ruth Lawrence’s Breastfeeding: A guide for the medical profession, Tech Comm Quarterly 9:271–289.Google Scholar
  139. 139.
    Hausman BL (2003) Mother’s milk: Breastfeeding controversies in American culture, Routledge.Google Scholar
  140. 140.
    Hawkes K, O’Connell JF, Blurton Jones NG, Alvarez H, Charnov EL (1998) Grandmothering, menopause, and the evolution of human life histories. PNAS 95:1336–1339.PubMedCrossRefGoogle Scholar
  141. 141.
    Binford SR & Binford LR (1969) Stone tools and human behavior. Sci. Amer 220:555–565.CrossRefGoogle Scholar

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© Springer Science + Business Media B.V. 2009

Authors and Affiliations

  • D. W. Sellen
    • 1
  1. 1.Departments of Anthropology, Nutritional Sciences and Public Health Sciences, and Centre for International HealthUniversity of TorontoTorontoCanada

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