Bruce Bagemihl - Biological Exuberance

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As a rough measure of the overwhelming attention devoted to male as opposed to female genitalia, for example, the Zoological Record for 1978—97 lists 539 articles that deal with the penis, compared to only 7 for the clitoris (the Zoological Record is a comprehensive electronic database that indexes more than a million zoological source documents, including articles from over 6,000 journals worldwide; the following keywords/search terms were used in compiling this estimate: penis/penile/penial/penes, phallus/phallic, baculum, hemipenes, clitorislclitorallclitorides, (os) clitoridis ).

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Stumptail Macaque (Goldfoot et al. 1980); Rhesus Macaque (Zumpe, D., and R. P. Michael [1968] “The Clutching Reaction and Orgasm in the Female Rhesus Monkey [ Macaca mulatta ],” Journal of Endocrinology 40:117—23). In what is perhaps the most extreme “experiment” of this type, female Rhesus Macaques were strapped to an apparatus made of iron and wood and forced to undergo stimulation with a dildo or “penis substitute” while their responses were monitored with electrodes (Burton, F. D. [1971] “Sexual Climax in Female Macaca mulatta,” in J. Biegert and W. Leutenegger, eds., Proceedings of the 3rd International Congress of Primatology , vol. 3, pp. 180-91 [Basel: S. Karger]).

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For a sample of some of this debate, see Allen, M. L., and W. B. Lemmon (1981) “Orgasm in Female Primates,” American Journal of Primatology 1:15—34; Rancour- Laferrière, D. (1983) “Four Adaptive Aspects of the Female Orgasm,” Journal of Social and Biological Structures 6:319-33; Baker, R., and M. A. Bellis (1995) Human Sperm Competition: Copulation, Masturbation, and Infidelity, pp. 234-49 (London: Chapman and Hall); Hrdy, S.B. (1996) “The Evolution of Female Orgasms: Logic Please but No Atavism,” Animal Behavior 52:851-52; Thornhill, R., and S. W. Gangstead (1996) “Human Female Copulatory Orgasm: A Human Adaptation or Phylogenetic Holdover,” Animal Behavior 52:853—55. For recent discussions that sidestep the question of sexual pleasure with regard to the “function” of the clitoris, as well as in relation to a variety of specific sexual behaviors (e.g., stimulatory movements such as thrusting during intercourse, multiple ejaculations, lengthy copulations, etc.), see Baker and Bellis, Human Sperm Competition , pp. 126—31; Eberhard, Female Control , pp. 142—46, 204—45, 248—54.

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A similar conundrum pertains to the “function” of the male copulatory organ in birds. Most male birds do not have a penis—insemination is achieved through simple contact of male and female genital apertures—and therefore its occurrence in some birds would appear to be, from a functional standpoint, “superfluous” (which could perhaps also be said about its occurrence in all other species). Moreover, in those species that do have a phallus (about 3 percent of all birds), its precise role in ejaculation and transporting semen remains unclear (see King, A. S. [1981] “Phallus,” in A. S. King and J. McLelland, eds., Form and Function in Birds , vol. 2, pp. 107—47 [London: Academic Press]; Briskie, J. V., and R. Montgomerie [1997] “Sexual Selection and the Intromittent Organ of Birds,” Journal of Avian Biology 28:73-86). In ratites such as Ostriches, Rheas, and Emus, as well as in Ducks and Geese, for example, the penis does not have an orifice connected to the male’s internal reproductive organs, and he simply ejaculates through his cloaca (at the base of the penis) as do all other male birds without a phallus. Although it carries a groove on its outside surface that may help direct semen during penetration, the penis does not transport semen internally. Moreover, in some birds such as buffalo weavers, the phallus has no such groove whatsoever (nor any internal ducts) and its role in sperm transport is even less clear. Consequently, the phallus’s reproductive “function” in these species is nearly as puzzling to biologists as that of the clitoris—the possibility that it could give sexual pleasure (to male and/or female) is rarely, if ever, even considered. Indeed, it is perhaps just as appropriate to speak of a male “clitoris” as it is of an actual “penis” in these cases, since the anatomy and function(s) of this organ may not be directly related to insemination (i.e., sperm transport). In addition, display of the phallus may also be an important element of courtship (as opposed to copulatory) activity in some species, as in the male Ostrich’s “penis-swinging” ceremony (Sauer and Sauer 1966:56-57) and possible penile displays in the white-billed buffalo weaver (Birkhead, T. R., M. T. Stanback, and R. E. Simmons [1993] “The Phalloid Organ of Buffalo Weavers Bubalornis ,” p. 330, Ibis 135:326-31).

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Scientists who have recognized that sexual pleasure (or related aspects such as sexual arousal, gratification, or libido, and/or sexual, affectionate, or “erotic” attraction) may play a significant role in homosexual and/or heterosexual interactions include: primates (Wolfe, “Human Evolution and the Sexual Behavior of Female Primates,” p. 144; Vasey, “Homosexual Behavior in Primates,” p. 196); Bonobo (Kano 1992:195-96, 1990:66; Thompson-Handler et al. 1984; de Waal 1995:45—46, 1997:1,4,104, 111, 158); Orang-utan (Maple 1980: 158—59); Rhesus Macaque (Hamilton 1914:317-18; Akers and Conaway 1979:78-79; Erwin and Maple 1976:13); Japanese Macaque (Vasey 1996); Stumptail Macaque (Chevalier-Skolnikoff 1976:525); Killer Whale (Rose 1992:116-17); Gray Whale (Darling 1978:60; 1977:10); Northern Elephant Seal (Rose et al. 1991:186); African Elephant (Buss 1990:20); Silver Gull (Mills 1994:57—58); Laughing Gull (Hand 1981:139-40); Sage Grouse (Scott 1942:495). See also M. O’Neil’s and J. D. Paterson’s replies to Small (Small, M. F. (1988) “Female Primate Sexual Behavior and Conception: Are There Really Sperm to Spare?” pp. 91-92, Current Anthropology 29:81—100), and P. Vasey’s recent comments in Adler, T. (1996) “Animals’ Fancies: Why Members of Some Species Prefer Their Own Sex,” Science News 151:8-9.

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Birkhead, T. (1995) “The Birds in the Trees Do It,” BBC Wildlife 13(2):46-50; Brown-headed Cowbird (Rothstein et al. 1986:127-28).

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For some specific examples, see Marais 1922/1969:196-97 (Savanna Baboon); Fradrich 1965:379 (Warthog); Greenhall 1965:450 (Vampire Bat); Kear 1972:85-86 (Swans); Kharitonov and Zubakin 1984:103 (Black-headed Gull), Coulson and Thomas 1985:20 (Kittiwake); Nuechterlein and Storer 1989:341 (Grebes); Székely et al., “An Evolutionary Approach to Offspring Desertion in Birds,” pp. 272—73.

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Common Murre (Birkhead and Nettleship 1984:2123-25).

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Virtually any of the references provided in the preceding notes will offer a sense of the ongoing debate and confusion about the “function” of each of these phenomena. For further examples, see: Adoption —Hansen, T. F. (1995) “Does Adoption Make Evolutionary Sense?” Animal Behavior 51: 474-75.

Nonreproductive copulations —Hatchwell 1988 (Common Murre); Small, “Female Primate Sexual Behavior and Conception.”

Multiple copulations —Gowaty, P. A. (1996) “Battles of the Sexes and Origins of Monogamy,” in J. M. Black, ed., Partnerships in Birds: The Study of Monogamy, pp. 21-52 (Oxford: Oxford University Press); Hunter, F. M., M. Petrie, M. Otronen, T. Birkhead, and A. P. Møller (1993) “Why Do Females Copulate Repeatedly With One Male?” Trends in Ecology and Evolution 8:21-26; Petrie, M. (1992) “Copulation Behavior in Birds: Why Do Females Copulate More Than Once with the Same Male?” Animal Behavior 44:790-92.