Sex at Dawn: The Prehistoric Origins of Modern Sexuality (59 page)

brian.htm):
Tribal, “Ethnic,” and Global Wars,
and
Ten
Points on War,
which includes a broad discussion of biology, archaeology, and the Yanomami controversy. Borofsky (2005) offers a balanced account of the controversy and the context in which it occurred. Of course, Chagnon’s work is readily available as well.

30. Quoted in Tierney (2000), p. 32.

31.
Washington Post
review of
Darkness in El Dorado:
Jungle Fever,
by Marshall Sahlins, Sunday, December 10, 2000, p. X01.

32. Chagnon (1968), p. 12.

33. Tierney (2000), p. 14.

34. Sponsel (1998), p. 104.

35. October 23, 2008.

Chapter 14: The Longevity Lie (Short?)
1. Note that these numbers are for demonstration purposes only. To keep it simple (and since it’s meaningless anyway), we haven’t adjusted for male/female size differences, regional variations in average infant skeleton sizes, and so on.

2. October 6, 2008.

3. Adovasio et al. (2007), p. 129.

4. Gina Kolata, “Could We Live Forever?,” November 11, 2003.

5.
Scientific American,
March 6, p. 57.

6. Harris (1989), pp. 211–212.

7. http://www.gendercide.org/case_infanticide.html.

8. These numbers don’t include the selective abortion of female fetuses, which is widespread in these countries. For example, Agence-France Presse reports that selective abortions have left China with 32 million more men than women, and that in just one year (2005), more than 1.1

million more boys than girls were born in China.

9. Philosopher Peter Singer has written thought-provoking books and essays on the question of how to calculate the value of human versus nonhuman life. See, for example, Singer (1990).

10. Cited in Blurton Jones et al. (2002).

11. Blurton Jones et al. (2002).

12. See Blurton Jones et al. (2002).

13. An excellent paper highly recommended to readers interested in these matters is Kaplan et al. (2000). The paper can

be

downloaded

at

Kaplan’s

faculty

website:

www.unm.edu/~hebs/pubs_kaplan.html.

14. From the paper by Kaplan et al. cited above, p. 171.

15. Readers interested in seeing how these same agricultural curses are playing out in the modern world might want to read Michael Pollan’s
In Defense of Food: An Eater’s Manifesto
(2009).

16. Larrick et al. (1979).

17. Source: Diamond (1997).

18. Edgerton (1992), p. 111.

19. Cohen et al. (2009).

20. Horne et al. (2008).

21. While we’re on the subject of hammocks, we’d like to take

this

opportunity

to

formally

propose

that

hammocks—not spear points or stone blades—were the first example of human technology. That no hard evidence for this proposal has been unearthed is due to hammocks being made of perishable fibers. (Who wants a stone hammock?) Even chimps and bonobos fashion primitive hammocks by weaving together tree branches for sleeping platforms.

22. See Sapolsky (1998) for an excellent overview of how stress affects us. On the question of human/bonobo similarities concerning stress, it’s interesting to note that when bombs fell near them in World War II,
all
the bonobos in the zoo died from the stress the explosions caused, while
none
of the chimps perished (according to de Waal and Lanting, 1998).

23.
The New Yorker,
June 26, 2006, p. 76.

Part IV: Bodies in Motion

1. This quote is taken from a debate between Gould on one side and Steven Pinker and Daniel Dennett on the other. Well worth reading, if you like high-brow discussion with plenty of low blows, is “Evolution: The Pleasures of Pluralism,”
The
New York Review of Books
44(11): 47–52.

2. Potts (1992), p. 327.

Chapter 15: Little Big Man

1. Miller (2000), p. 169.

2. Though not always, as other factors can influence body-size dimorphism, apart from the intensity of male-male mating conflict. See Lawler (2009), for example.

3. Male
Australopithecus
(between three and four million years ago) are thought to have been about fifty percent larger than females. Recent papers suggest
Ardipethicus ramidus,
another supposed human ancestor (thought to be a million or so years older than
Australopithecus)
was closer to our 15 to 20 percent levels. But keep in mind that the much-ballyhooed reconstruction of
Ardipethicus ramidus
relied upon bits and pieces of many different individuals, so our sense of body size dimorphism 4.4 million years ago is based upon educated guesses, at best (White et al., 2009).

4. Lovejoy (2009).

5.

http://www.psychologytoday.com/articles/200706/

ten-politically-incorrect-truths-about-human-nature.

6. Supplemental note. On sexual selection in relation to monkeys. Reprinted from
Nature,
November 2, 1876, p. 18.

http://sacred-texts.com/aor/darwin/descent/dom25.htm.

7. As we’ll discuss in the next chapter, the
genital echo theory
posits that women developed pendulous breasts so that the cleavage would mimic the (is there a scientific term for this?) butt-crack that so enticed our primate ancestors. Following that line of reasoning, some argue that fancily named lipstick serves to re-create the bright red “hinder ends” that so perplexed poor Darwin.

8. See Baker and Bellis (1995) or Baker (1996) for the sperm-team theory.

9. Hrdy (1996) is a wonderfully erudite and engaging discussion of how some of Darwin’s personal sexual hang-ups are reflected still in evolutionary theory.

10. Supplemental note. On sexual selection in relation to monkeys. Reprinted from
Nature,
November 2, 1876, p. 18.

http://sacred-texts.com/aor/darwin/descent/dom25.htm.

11. Diamond (1991), p. 62.

Chapter 16: The Truest Measure of a Man
1. de Waal (2005), p. 113.

2. In Barkow et al. (1992), p. 299.

3. Barash and Lipton (2001), p. 141.

4. Pochron and Wright (2002).

5. Wyckoff et al. (2000). Other research looking into primate testicular genetics has reinforced the impression that ancestral human mating behavior more closely resembled the promiscuity of chimps than the one-male-at-a-time gorillas.

See, for example, Kingan et al. (2003), who conclude that although “predicting the expected intensity of sperm competition in ancestral
Homo
is controversial, … we find patterns of nucleotide variability at SgI in humans to resemble more closely the patterns seen in chimps than in gorillas.” 6. Short (1979).

7. Margulis and Sagan (1991), p. 51.

8. Lindholmer (1973).

9. For more on this, see work by Todd Shackelford, particularly Shackelford et al. (2007). Shackelford generously makes most of his published work available for free download at http://www.toddkshackelford.com/publications/

index.html.

10. Symons (1979), p. 92. Although we probably disagree with half of his conclusions, and much of the science is out of date, Symons’s book is well worth reading for its wit and artistry alone.

11. Harris (1989), p. 261.

12. Sperm competition is an area of passionate debate. Space limitations (and quite possibly, readers’ interest) preclude us from a more thorough discussion—especially concerning the highly controversial claims of Baker and Bellis regarding sperm teams composed of specialized cells acting as

“blockers,” “kamakaze,” and “egg-getters.” For a scientific review of their findings, see Baker and Bellis (1995). For a popularized review, see Baker (1996). For a balanced discussion of the controversy written by a third party, see Birkhead (2000), especially pp. 21–29.

13. Data primarily from Dixson (1998).

14. See, for example, Pound (2002).

15. Kilgallon and Simmons (2005).

16. Some readers will argue that these conventions in contemporary pornography are expressions of female subjugation and degradation rather than eroticism. Whether or not this is the case (a discussion we’re going to sidestep at this juncture), one must still ask why it is being expressed in this way, with these images, given that there are so many ways of visibly humiliating a person. Some authorities believe the practice of
bukkake
originated as a way of punishing adulterous women in Japan—a somewhat less Puritanical
Scarlet Letter,
if you will (see, for example, “Bake a Cake? Exposing the Sexual Practice of Bukkake,” poster presented at the 17th World Congress of Sexology, by Jeff Hudson

and

Nicholas

Doong:

http://abstracts.co.allenpress.com/pweb/sexo2005/document/

50214). If you don’t know what
bukkake
is, and you’re even slightly prone to being offended, please forget we even mentioned it.

Chapter 17: Sometimes a Penis Is Just a Penis
1. Frans de Waal suspects that bonobos have longer penises than humans, at least relative to body size, but most other primatologists seem to disagree with his assessment. In any case, there is no question that the human penis is far thicker than that of any other ape, in absolute terms or relative to body size, and far longer than that of any primate not clearly engaged in extreme sperm competition.

2. Sherfey (1972), p. 67.

3. One species of gibbon, the black-crested gibbon
(Hylobates
concolor),
does in fact have an external, pendulous scrotum.

Interestingly, this type of gibbon may also be exceptional in
not
being strictly monogamous (see Jiang et al., 1999).

4. Gallup (2009) offers an excellent summary of this material.

5. Dindyal (2004).

6.

http://news.bbc.co.uk/go/pr/fr/-/2/hi/health/7633400.stm 2008/09/24.

7. Harvey and May (1989), p. 508.

8. Writing in the
Encyclopedia of Human Evolution,
Robert Martin notes, “Relative to body size, humans have a very low value for rmax—even in comparison with other primates.

This suggests that selection has favoured a low breeding potential during human evolution. Any model of human evolution should take this into account.” A low rmax value along with the very high levels of sexual activity typical of humans is yet another indication that sex has long functioned for nonreproductive purposes in our species.

Similarly, while Dixson (1998) characterizes the seminal vesicles of monogamous and polygynous primates (except the gelada baboon) as vestigial or small, he classifies the human seminal vesicles as medium—noting that “it is reasonable to propose that natural selection might have favoured reduction in size of the vesicles under conditions where copulation is relatively infrequent and the need for large ejaculate volume and coagulum formation is reduced.” He goes on to propose that “this might explain the very small size of the vesicles in primarily monogamous [primates].”

9.
BBC News
online, July 16, 2003.

10.
BBC News
online, October 15, 2007.

11.
Psychology Today,
March/April 2001.

12. Barratt et al. (2009).

13. Hypothetically, one could try to falsify this hypothesis using data on testicular volume and sperm production from some of the societies we’ve discussed where sperm competition and partible paternity are in effect. To this end, we’ve contacted every anthropologist we could locate who has worked in the Amazon (or anywhere else with hunter-gatherers), but no one seems to have managed to gather these delicate data. Still, even if it were found that males in these societies showed higher testicular volume and sperm production, as our hypothesis predicts, definitive confirmation of the hypothesis would be precluded by the relative absence of the environmental toxins that are presumably at least partly responsible for testicular atrophy in industrialized societies.

14.
BBC News
online, December 8, 2006.

15. Diamond (1986).

16. W. A. Schonfeld, “Primary and Secondary Sexual Characteristics. Study of Their Development in Males from Birth through Maturity, with Biometric Study of Penis and Testes,”
American Journal of Diseases in Children
65, 535–549 (cited in Short, 1979).

17. Harvey and May (1989).

18. Baker (1996), p. 316.

19. Bogucki (1999), p. 20.

Chapter 18: The Prehistory of O

1. Maines’s book has become an underground sensation.

Written as a serious cultural history of the vibrator, the story she tells is surprising and compelling. As we write, a play based on the book written by Sarah Ruhl
(In the Next Room)
is playing on Broadway. A National Public Radio story on the play

is

here:

http://www.npr.org/templates/story/

story.php?storyId=20463597&ps = cprs.

2. Quotes taken from Margolis (2004).

3. See Money (2000). Interestingly, semen depletion is central to the ancient Taoist understanding of male health and sexuality as well. See, for example, Reid (1989).

4. On Baker Brown, see Fleming (1960) and Moscucci (1996).

5. Coventry (2000).

6. Although the clitoris is often referred to as “the only organ in the human body whose sole function is to provide pleasure,” there are two problems with this observation. First, if female orgasm (pleasure) is functional in the senses we outline

(increases

chances

of

fertilization,

inspires

vocalizations, and thereby promotes sperm competition), then there is clearly a purpose to the pleasure. Secondly, what about male nipples? Not all men find them to be a site of pleasure, but they are certainly highly enervated and serve no functional purpose.

7. Margolis (2004), pp. 242–243.

8. Ironically, according to archaeologist Timothy Taylor (1996), this image of the Devil is thought to be derived from
Cernunnos,
the horned god, who was the Celtic translation of Indian tantric practice and thus originally a symbol of spiritual transcendence via sexual practice.