Abstract
All primates except human beings have thick coats of body hair. This suggests the primate ancestors of human beings likewise had such body hair and that, for some evolutionary reason, lost their body hair. Various theories have been put forward but none is fully adequate. This article presents the “naked love theory.” This theory locates the origin of human hairlessness in the ancestral mother-infant relationship. In this view, hairlessness is ultimately the adaptive consequence of bipedalism. Because of bipedalism, ancestral infants lost their prehensile feet and thus lost the ability to grasp the mother’s fur with their feet, as do other primate infants. Early bipedal mothers were thus under pressure to carry the infant. Therefore infants survived only if mothers had a strong desire to hold them. Because of the pleasure of skin-to-skin contact, the desire to hold the infant would have been stronger in mothers possessing a hairless mutation that enabled them to give birth to hairless infants. Survival of these infants would have then been greater than that of hair-covered infants. The hairlessness that began to appear in this context of maternal selection was then reinforced by sexual selection in the male-female sexual relationship. This is because a hairless sexual partner would have enabled the hairless individual to recreate the pleasure of skin-to-skin contact in the mother-infant relationship. This theory then helps to explain the evolutionary origins of romantic love.
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References
Amiel-Tison C, Grenier A (1986) A Neurological Assessment During the First Year of Life. New York: Oxford University Press.
Avery MD, Duckett L, Frantzich CR (2000) The experience of sexuality during breastfeeding among primiparous women. Journal of Midwifery & Woman’s Health 45: 227–237.
Bard KA (1995) Parenting in primates. In: Handbook of Parenting. Vol. 2, Biology and Ecology of Parenting (Bornstein MH, ed), 27–58. Mahwah, NJ: Erlbaum.
Boesch C, Boesch H (1984) Mental maps in chimpanzees: An analysis of hammer transports for nut cracking. Primates 25: 160–170.
Cantrill R (2006) Influence of Naked Body Contact Between Mother and Newborn on Effective Breastfeeding. Doctoral dissertation, Griffith University, Queensland, Australia.
Cavalli-Sforza LL, Feldman MW (1981) Cultural Transmission and Evolution: A Quantitative Approach. Princeton, NJ: Princeton University Press.
Cutler WB, Preti G, Krieger A, Huggins GR, Garcia CR, Lawley HJ (1986) Human axillary secretions influence women’s menstrual cycles: The role of donor extract from men. Hormones and Behavior 20: 463–473.
Darwin C (1871) The Descent of Man, and Selection in Relation to Sex, Vol. 2. London: John Murray.
De Waal F (1995) Bonobo sex and society: The behavior of a close relative challenges assumptions about male supremacy in human evolution. Scientific American 272(3): 82–88.
Frayer DW, Wolpoff MH (1985) Sexual dimorphism. Annual Review of Anthropology 14: 429–473.
Gallup GG, Burch RL, Zappieri ML, Parvez RA, Stockwell ML, Davis JA (2003) The human penis as a semen displacement device. Evolution and Human Behavior 24: 277–289.
Giles J (1994) A theory of love and sexual desire. Journal for the Theory of Social Behaviour 24: 339–357.
Giles J (1999) Sartre, sexual desire, and relations with others. In: French Existentialism: Consciousness, Ethics, and Relations with Others (Giles J, ed), 155–174. Amsterdam: Rodopi.
Giles J (2004) The Nature of Sexual Desire. Westport, CT: Praeger.
Giles J (2006) Social constructionism and sexual desire. Journal for the Theory of Social Behaviour 36: 226–238.
Giles J (2008) Sex hormones and sexual desire. Journal for the Theory of Social Behaviour 38: 45–66.
Goodall J (1986) The Chimpanzees of Gombe: Patterns of Behavior. Cambridge, MA: Harvard University Press.
Hardy A (1960) Was man more aquatic in the past? New Scientist 7: 642–645.
Harlow HF, Zimmermann RR (1958) The development of affectional responses in infant monkeys. Proceedings of the American Philosophical Society 102: 501–509.
Harris JR (2006) Parental selection: A third selection process in the evolution of human hairlessness and skin color. Medical Hypotheses 66: 1053–1059.
Herbenick D, Schick V, Reece M, Sanders S, Fortenberry JD (2010) Pubic hair removal among women in the United States: Prevalence, methods, and characteristics. Journal of Sexual Medicine 7: 3322–3330.
Hewes GW (1961) Food transport and the origin of hominin bipedalism. American Anthropologist 63: 687–710.
Hunt M (1974) Sexual Behavior in the 1970s. Chicago: Playboy Press.
Hupka RB (1981) Cultural determinants of jealousy. Alternative Lifestyles 4: 310–356.
Islam MA, Feeroz MM (1992) Ecology of Hoolock gibbon of Bangladesh. Primates 33: 451–464.
Jablonski NG (2010) The naked truth. Scientific American (February): 42–49.
Jolly C (1970) The seed-eaters: A new model of hominin differentiation based on a baboon analogy. Man 5: 5–28.
Kaplan G, Rogers LJ (1999) The Orang-Utans. London: Allen and Unwin.
Kasai K (1995) Nihon Josei no Gaiseishokuki (External Genitalia of Japanese Females). Tokyo: Free Press.
Kingston JD, Marino BD, Hill A (1994) Isotopic evidence of neogene hominin paleoenvironments in Kenya Rift Valley. Science 264: 955–959.
Kittler R, Kayser M, Stoneking M (2003) Molecular evolution of Pediculus humanus and the origin of clothing. Current Biology 13: 1414–1417.
Lewis B, Jurmain R, Kilgore L (2010) Understanding Humans: Introduction to Physical Anthropology and Archaeology, 10th ed. Belmont, CA: Wadsworth.
Lindenfors P, Gittleman JL, Jones KE (2007) Sexual size dimorphism in mammals. In: Sex, Size, and Gender Roles: Evolutionary Studies of Sexual Size Dimorphism (Fairbairn DJ, Blanckenhorn WU, Székely T, eds), 16–26. Oxford: Oxford University Press.
Miller SL, Maner JK (2009) Scent of a woman: Men’s testosterone responses to olfactory ovulation cues. Psychological Science 1: 276–283.
Mitani JC (1984) The behavioral regulation of monogamy in gibbons Hylobates muelleri. Behavioral Ecology and Sociobiology 15: 225–230.
Montagu A (1972) Touching: The Human Significance of the Skin. New York: Harper and Row.
Moore ER, Anderson GC, Bergman N (2007) Early skin-to-skin contact for mothers and their healthy newborn infants. Cochrane Database of Systematic Reviews 3: CD003519. DOI:10.1002/14651858.CD003519.pub2
Morgan E (1997) The Aquatic Ape Hypothesis. London: Souvenir Press.
Oakley K (1961) On man’s use of fire, with comments on tool-making and hunting. In: Social Life of Early Man (Washburn SL, ed), 176–193. Chicago: Aldine.
Pagel M, Bodmer W (2003) A naked ape would have fewer parasites. Proceedings of the Royal Society of London B 270: S117–S119.
Post PW, Szabó G, Keeling ME (1975) A quantitative and morphological study of the pigmentary system of the chimpanzee with the light and electron microscope. Amercian Journal of Physical Anthropology 43: 435–444.
Reichard U, Sommer V (1997) Group encounters in wild gibbons (Hylobates lar): Agonism, affiliation, and the concept of infanticide. Behaviour 134: 1135–1174.
Rogers AR, Iltis D, Wooding S (2004) Genetic variation at the MC1R locus and the time since loss of human body hair. Current Anthropology 45: 105–108.
SØrensen B (2009) Energy use by Eem Neanderthals. Journal of Archaeological Science 36: 2201–2205.
Stoddart DM (1990) The Scented Ape: The Biology and Culture of Human Odour. Cambridge: Cambridge University Press.
van Schaik CP, Hodges JK, Nunn CL (2000) Paternity confusion and the ovarian cycles of female primates. In: Infanticide by Males and its Implications (van Schaik CP, ed) 361–387. Cambridge: Cambridge University Press.
Widström AM, Ransjo-Arvidson AB, Christensson K, Matthiesen AS, Winberg J, Uvnas-Moberg K (1987) Gastric suction in healthy newborn infants: Effects on circulation and developing feeding behaviour. Acta Paediatrica Scandinavica 76: 566–572.
Wrangham R (2002) The cost of sexual attraction: Is there a trade off in female Pan between sex appeal and received coercion? In: Behavioural Diversity in Chimpanzees and Bonobos (Boesch C, Hohmann G, Marchant LF, eds), 204–215. Cambridge: Cambridge University Press.
Wyart C, Webster WW, Chen JH, Wilson SR, McClary A, Khan RM, Sobel N (2007) Smelling a single component of male sweat alters levels of cortisol in women. Journal of Neuroscience 27: 1261–1265.
Wyatt D (2003) Pheromones and Animal Behaviour: Communication by Smell and Taste. Cambridge: Cambridge University Press.
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Giles, J. Naked Love: The Evolution of Human Hairlessness. Biol Theory 5, 326–336 (2010). https://doi.org/10.1162/BIOT_a_00062
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DOI: https://doi.org/10.1162/BIOT_a_00062