Biological Exuberance: Animal Homosexuality and Natural Diversity - читать онлайн бесплатно полную версию книги . Страница 29

Snow Goose (Quinn et al. 1989); Ring-billed Gull (Kovacs and Ryder 1981); Red-backed Shrike (Pounds 1972); Blue Tit (Blakey 1996); Guianan Cock-of-the-Rock (Trail and Koutnik 1986); Stumptail Macaque (Chevalier-Skolnikoff 1976:522 [table III]); Jackdaw (Röell 1979:126-27); Cheetah (Eaton and Craig 1973:248, 250); Bonobo (Parish 1996:65, 86; de Waal 1997:112—15). Similarly, in citing Hartman’s (1971) original descriptions of homosexuality in West Indian Manatees, Ronald et al. (1978:37) focus on examples of same-sex activity that occur in conjunction with heterosexual behaviors and downplay those that are independent of opposite-sex encounters (even though such independent encounters are equally, if not more, prevalent). On a related point, genes that are thought to control homosexual activity in Fruit Flies have been given names by scientists that refer solely to their (negative) effect on heterosexuality and breeding. One gene has been labeled dissatisfaction (alluding to the fact that carriers of this gene, in addition to being interested in homosexual activity, typically refuse or are “dissatisfied” with heterosexual advances), while another has been called fruitless (alluding to the fact that carriers, in addition to courting individuals of both sexes, are infertile) (Finley et al. 1997:917).

Savanna (Olive) Baboon (Owens 1976:254); Right Whale (Clark 1983:169); Moose (Van Ballenberghe and Miquelle 1993:1688); Cattle Egret (Fujioka and Yamagishi 1981:136).

Squirrel Monkey (Talmage-Riggs and Anschel 1973:70-71); Bonobo (Savage-Rumbaugh and Wilkerson 1978:338; Savage and Bakeman 1978:614); Spotted Hyena (Burr 1996:118-19). For conflicting information on the occurrence of clitoral penetration in Spotted Hyenas, see Glickman (1995). See also Morris (1956:261), who defines courtship as “the heterosexual reproductive communication system leading up to the consummatory sexual act” (Morris, D. [1956] “The Function and Causation of Courtship Ceremonies,” in M. Autuori and Fondation Singer-Polignac, L‘instinct dans le comportement des animaux et de l’homme [Paris: Masson et Cie.])

Savanna (Chacma) Baboon (Marais 1922/1969:215).

Ruff (van Rhijn 1991:21); Bonnet Macaque (Nolte 1955:179).

Walrus (Miller and Boness 1983:305); African Elephant (Shelton 1965:163-64); Gorilla (Maple, T. [1977] “Unusual Sexual Behavior of Nonhuman Primates,” in J. Money and H. Musaph, eds., Handbook of Sexology, pp. 1169-70 [Amsterdam: Excerpta Medica]); Sage Grouse (Scott 1942:495); Hanuman Langur (Mohnot 1984:349); Common Chimpanzee (Kortlandt 1962:132); Musk-ox (Reinhardt 1985:297-98); Mallard Duck (Lebret 1961:111—12); Blue-bellied Roller (Moynihan 1990:17); Lion (Cooper 1942:26-28); Orang-utan (Rijksen 1978:257); Savanna Baboon (Noë 1992:295, 311); Mule Deer (Halford et al. 1987:107); Hammerhead (Brown 1982:171; Campbell 1983:11); Bonobo (Thompson-Handler et al. 1984:358; de Waal 1987:319, 1997:102); Japanese Macaque (Green 1975:14); Rhesus Macaque (Reinhardt et al. 1986:56); Red Fox (Macdonald 1980:137); Squirrels (Ferron 1980; Horwich 1972; Reilly 1972). A few of these terms are also applied to nonreproductive heterosexual activities, in which case the attribution of “falseness” refers to the fact that the behavior does not result in procreation rather than to a same-sex context per se. See chapter 5 for further discussion of the parallel treatment of nonreproductive heterosexual behaviors as “abnormal” in the history of zoology.

The categorization of homosexual activity as less than “genuine” sexual activity is an important issue, and the various ways that same-sex activity is desexualized will be examined in greater detail in the next section.

Bonobo (Kano 1992); Common Chimpanzee (de Waal 1982); Snow Goose (Diamond 1989); Lesser Flamingo (Alraun and Hewston 1997); Oystercatcher (Heg and van Treuren 1998); Black-billed Magpie (Baeyens 1979); Black Stilt (Reed 1993); Fruit Flies (Cook 1975); Long-legged Fly sp. (Dyte 1989).

Gowaty, P. A. (1982) “Sexual Terms in Sociobiology: Emotionally Evocative and Paradoxically, Jargon,” Animal Behavior 30:630—31. The title of the article in question (Abele and Gilchrist 1977, on Acanthocephalan Worms) also contained the word rape, so it is possible that scientists were “snickering” at this as well. Gowaty suggests replacing, along with unisexual for homosexual, all “loaded” terminology with more “neutral” words, e.g., forced copulation for rape, kleptogamy for cuckoldry, one-male social unit for harem. Many of her arguments for such alternate terminology are valid, e.g., that the “loaded” terms are often scientifically inaccurate. Notably, however, her principal argument against the word homosexual is not that it is inaccurate, but that use of this term is “sensationalistic” and triggers the prejudices of other scientists, thereby preventing them from seeing past the word to what it describes. It should also be pointed out that many formerly controversial terms for heterosexual behaviors are now acceptable in scientific circles. The word divorce, for example, was first greeted with an “uproar” when used to describe the break-up of pair-bonds in birds, and numerous scientists suggested replacing it with more “neutral” words; yet the term is now widely used in the ornithological literature (Milius, S. [1998] “When Birds Divorce: Who Splits, Who Benefits, and Who Gets the Nest,” p. 153, Science News 153:153-55).

Giraffe (Coe 1967:320; Leuthold, W. [1977] African Ungulates: A Comparative Review of Their Ethology and Behavioral Ecology, p. 130 [Berlin: Springer-Verlag]).

Connor, J. (1997) “Courtship Testing,” Living Bird 16(3)31-32; Depraz, V, G. Leboucher, L. Nagle, and M. Kreutzer (1997) “‘Sexy’ Songs of Male Canaries: Are They Necessary for Female Nest-Building?” in M. Taborsky and B. Taborsky, eds., Contributions to the XXV International Ethological Conference, p. 122, Advances in Ethology no. 32 (Berlin: Blackwell Wissenschafrs-Verlag); Emlen, S. T., and N. J. Demong (1996) “All in the Family,” Living Bird 15(3):30-34; Savanna Baboon (Smuts 1985:223, 1987:39, 43); Tasmanian Native Hen (Goldizen et al. 1998); Mirande, C. M., and G. Archibald (1990) “Sexual Maturity and Pair Formation in Captive Cranes at the International Crane Foundation,” in AAZPA Annual Conference Proceedings, pp. 216-25 (Wheeling, W.Va.: American Association of Zoological Parks and Aquariums); Bonobo (de Waal 1997:117); Eisner, T., M.A. Goetz, D. E. Hill, S. R. Smedley and J. Meinwald (1997) “Firefiy ‘Femmes Fatales’ Acquire Defensive Steroids (Lucibufagins) from Their Firefly Prey,” Proceedings of the National Academy of Sciences 94:9723-28; Domestic Goat (Shank 1972:500). See also the discussion of red-cockaded woodpecker “family values” in chapter 2.

Greylag Goose (Lorenz 1991:241-43) (see also Lorenz’s own assertion, in this same passage, that such male pairs are not simply platonic “friendships” between males but are equivalent to male-female mated pairs). Analogously, Kortlandt (1949) (Great Cormorant) labels same-sex pairs “pseudohomosexual” rather than “homosexual” if their members later form heterosexual bonds, once again equating “true” homosexuality with lifetime, exclusive same-sex pairing. See chapter 2 for more on the dubious notion of “true” homosexuality and its relation to more sophisticated characterizations of sexual orientation. Lorenz’s unwillingness to apply the term homosexual to gander pairs and thereby invite human-animal comparisons (or imply full heterosexual-homosexual equivalence) is especially problematic in light of his activities during the Third Reich. As a member of the Nazi party in Austria and an official lecturer for its Office of Race Policy, Lorenz did not hesitate to draw analogies between animals and people to support and develop the doctrines of “biological degeneracy,” “racial purity,” and the “elimination” of “inferior” or “asocial” elements (Deichmann, U. [1996] Biologists under Hitler, especially “Konrad Lorenz, Ethology, and National Socialist Racial Doctrine,” pp. 179-205. Cambridge, Mass.: Harvard University Press). Among his most blatant assertions in this regard are statements (in 1943) that physical and moral “decay” in people is “identical” to the effects of domestication on animals and (in 1940) that the “defective type” among humans is like “the domesticated animal that can be bred in the dirtiest stable and with any sexual partner” (ibid., pp. 186, 188; cf. Lorenz’s [1935/1970:203] surmise that same-sex pairing in Jackdaws only occurs in captive animals and is not a feature of “natural” populations). He also asserted (in 1941) that “Precisely in the large field of instinctive behavior, humans and animals can be directly compared … . We confidently venture to predict that these studies will be fruitful for both theoretical as well as practical concerns of race policy” (ibid., p. 186). The subject of how the antihomosexual climate of Nazi Germany and the Nazi sympathies of some biologists helped shape the scientific discourse on animal homosexuality deserves further investigation. Many zoological studies of this phenomenon, after all, were written in Germany and Austria during this period or were heavily influenced by work that had its genesis during this time. Moreover, one of the earliest scientific surveys of animal homosexuality (Karsh, “Päderastie und Tribadie bei den Tieren” [1990]), appeared in the periodical Jahrbuch für sexuelle Zwischenstufen (Yearbook for Sexual Intermediate Types), published by the noted Jewish homosexual Magnus Hirschfield, whose mammoth archives and library of sexology were later destroyed by the Nazis.

Western Gull (Hayward and Fry 1993). See also Diamond and Burns, who suggest that same-sex pairing in Gulls should be referred to as “joint brooding” or “coparenting” rather than as homosexuality, thereby emphasizing its supposed reproductive functions (Diamond, M., and J. A. Burns [1995] “Human-Nonhuman Comparisons in Sex: Valid and Invalid,” paper presented at the 24^th International Ethological Conference, Honolulu, Hawaii). For arguments that same-sex pairing is not primarily a reproductive behavior, see chapters 4 and 5.

For examples of scientists who use the term homosexual (or lesbian or gay) even when no overt sexual activity is involved (i.e., to refer to related behaviors such as courtship, pairing, or parenting), see Sauer 1972 (Ostrich), Nethersole-Thompson 1975 (Scottish Crossbill), Wingfield et al. 1980 (Western Gull), Braithwaite 1981 (Black Swan), Smith 1988 (Lyrebird), Diamond 1989 (Snow Goose), Reed 1993 (Black Stilt).

And in fact just such a “broad” definition of heterosexuality is required in many cases. “Heterosexual pairs” in which little or no sexual activity occurs between partners have been reported for Greylag Geese (as mentioned above) and Lesser Scaup Ducks (Afton 1985:150), among others; see also Loy (1971:26) for “sexual” bonds between male and female Rhesus Macaques that do not involve mounting or copulation, and Smuts (1985:18, 163—66, 199, 213) on the platonic “pair-bonds” or “friendships” between male and female Savanna Baboons. In addition, in some “heterosexual pairs” of splendid fairy-wrens all offspring are fathered by males other than the female’s pair-bonded mate (i.e., she does not copulate—or at least is not fertilized by—her partner); see Russell, E., and L Rowley (1996) “Partnerships in Promiscuous Splendid Fairy-wrens,” in J. M. Black, ed., Partnerships in Birds: The Study of Monogamy, pp. 162-73 (Oxford: Oxford University Press). For an example of a “broad” definition of (hetero)sexuality that encompasses courtship activities in addition to overt copulatory behavior, see Tinbergen, N. (1965) “Some Recent Studies of the Evolution of Sexual Behavior,” in F. A. Beach, ed., Sex and Behavior, pp. 1—33 (New York: John Wiley and Sons).

In discussing the possible dangers of anthropomorphism in terminology, the comments of biologist John Bonner are instructive: “An anthropologist might find the use of words such as slaves or castes for ant colonies most undesirable … . For instance, it implies that the most repugnant human morals are ascribed to the members of some species of ant … . Much worse, it could imply that if ants have slavery, it is a natural thing to do and therefore quite justified in a human society. These arguments are not quite rational and can only be advanced under extreme fervor of one sort or another. A more reasoned objection would be that the motivations of ants and men might differ radically, but by using the same words this distinction is lost. A biologist, on the other hand, feels that the points made above are too obvious to interfere with the dual use of the words. He does not see any problem: in both ant and human slavery individuals forcibly capture members of their own species or related species and cause their captives to do work for the benefit of the captors. It is unnecessary to drag in all the possible political, psychological, or strictly human nuances; a very simple definition of the word is sufficient. There is no need to be tyrannized by words. If a biologist may not use the common words, he will be forced to invent a whole new set of jargon terms for nonhuman societies, an unfortunate direction since there are too many jargon words in any science as it is. I hope it will be sufficient if I make it clear in the beginning that words either invented or frequently used for human societies will also be used for animal societies with the understanding that I am not implying anything human in their meaning; they are to be considered simple descriptions of conditions.” (Bonner, J. T. [1980] The Evolution of Culture in Animals, pp. 9—10. [Princeton, N.J.: Princeton University Press].) Unfortunately, this eminently reasonable position has not been adopted by most biologists where homosexuality is concerned; for a counterview, sec Gowaty, “Sexual Terms in Sociobiology.”

Examples of species in which homosexual activity is given only cursory treatment compared to heterosexual activity are too numerous to list, but include White-tailed Deer (Hirth 1977), Wapiti (Harper et al. 1967), Fat-tailed Dunnart (Ewer 1968), Matschie’s Tree Kangaroo (Hutchins et al. 1991), Wattled Starling (Sontag 1991), Sage Grouse (Wiley 1973, Gibson and Bradbury 1986), and Canary-winged Parakeet (Arrowood 1988). In a few studies, however, detailed quantitative and descriptive information is provided on homosexual behavior; see, for example, Kitamura 1989, Kano 1992, de Waal 1987, 1995, 1997 (Bonobo); Edwards and Todd 1991 (White-handed Gibbon); Hanby 1974, Eaton 1978, Chapais and Mignault 1991, Vasey 1996 (Japanese Macaque); Pratt and Anderson 1985 (Giraffe); Jamieson and Craig 1987a (Pukeko); van Rhijn and Groothuis 1985, 1987 (Black-headed Gull); Rogers and McCulloch 1981 (Galah). For further discussion of how same-sex activity has frequently not been considered “genuine” sexual behavior, see the next section.

Spinner Dolphin (Wells 1984:468; Bateson 1974); Kob (Buechner and Schloeth 1965:219 [table 21]); Crested Black Macaque (Dixson 1977); Brown Capuchin (Linn et al. 1995); Giraffe (Dagg and Foster 1976:75—77).

Western Gull (Hunt et al. 1984:160) (see Hayward and Fry [1993:16, 18] for a recent reiteration of the findings of this study, in which sexual activity is once again downplayed); Black-crowned Night Heron (Noble et al. 1938:28-29); on comparable levels of crowding in wild colonies, see Gross 1923:13—15; Davis 1993:6; Kazantzidis et al. 1997:512); Laughing Gull (Hand 1985:128); Canary-winged Parakeet (Arrowood 1988. 1991); Greater Rhea (Fernández and Reboreda 1998:341); Zebra Finch (Burley 1981:722).

Gorilla (Harcourt 1979a:255). Harcourt et al. (1981:266) also characterize heterosexual copulation as “rare.” In addition, they report directly observing only 69 episodes of heterosexual mating (other copulations were heard but not seen) compared to 10 episodes between females, which yields an even higher proportion of nearly 13 percent homosexual activity.

Western Gull (Hunt et al 1980:474); Spotted Hyena (Glickman 1993; Burr 1996:118-19); for further discussion of comparisons between wild and captive animals, see the next chapter

Tree Swallow (M. P. Lombardo, personal communication: Venier et al. 1993:413; Lombardo 1986; Leffelaar and Robertson 1984:78). Similarly, homosexual mounting is claimed to be very rare in Northern Fur Seals, yet most heterosexual matings in this species are missed by observers because they occur at night (Gentry 1998:75—77, 107, 145).

For specific examples, see Nilgiri Langur (Poirier 1970; Hohmann 1989). White tailed Deer (Hirth 1977: Rue 1989), Mule Deer (Geist 1981; Halford et al. 1987; Wong and Parker 1988), Red Deer (Lincoln et al. 1970; Guiness et al. 1971; Hall 1983), American Bison (McHugh 1958: Lott 1983 and personal communication), Red Squirrel (Layne 1954; Smith 1968; Ferron 1980), Mallard Duck Ramsey 1956; Lebret 1961; Schutz 1965; Bossema and Roemers 1985; Geh 1987), Ruff (Selous 1906—7; Bogan-Warburg 1966; Scheufler and Stiefel 1985; van Rhijn 1991), Oystercatcher (Makkink 1942; Heg and van Treuren 1998), Hooded Warbler (Niven 1994 and personal communication), Cliff Swallow (Emlen 1954, Barlow et al. 1963; Brown and Brown 1996), Red-backed Shrike (Owen 1946; Ashby 1958; Pounds 1972), Victoria’s Riflebird (Bourke and Austin 1947; Frith and Cooper 1996; C. B. Frith, personal communication), Sage Grouse (Scott 1942; Patterson 1952; Wiley 1973; Gibson and Bradbury 1986), Acorn Woodpecker (MacRoberts and MacRoberts 1976; Troetschler 1976; W. D. Koenig, personal communication), Gentoo Penguin (Robert 1934; Wheater 1976; Stevenson 1983), and the examples of wild versus captive observations in notes 99-100, chapter 4.

Pukeko (Craig 1980:594; Jamieson and Craig 1987a;1252); Blak-headed Gull (van Rhijn and Groothuis 1985:161, 165).

For example, Vasey (“Homosexual Behavior in Primates,” p. 181) sets up a general frequency scale in which homosexual behavior is classified as “rare” if it occurs “5 percent or less frequently as heterosexual behavior” and “occasional” if it occurs “6—24 percent as frequently as heterosexual behavior”; it is regarded as “frequent” only if it occurs “25 percent or more frequently.”Certainly this scale is to be commended for its standardization and multipoint assessment criteria (which also include nonquantitative measures); yet (like most scales) it is not without arbitrarines, and it is at odds with the heterosexual “5 percent” criterion. The “Polygyny threshold” model, which recognizes a frequency of ≥5 percent as significant for “minority” heterosexual mating systems (i.e., polygamy in otherweise monogamous species) was originally proposed by Verner, J., and M. P. Willson (1966) “The Influence of Habitats on Mating Systems of North American Passerine Birds,” Ecology 47:143-47. The 5 percent threshold continues to be widely used as a criterion for “regular” polygyny—for more recent examples, see Quinney 1983 (Tree Swallow); Moller, A. P. (1986) “Mating Systems Among European Passerines. A Review,” Ibis 128:234—50; Petit, L. J. (1991) “Experimentally Induced Polygyny in a Monogamous Bird Species: Prothonotary Warblers and the Polygyny Threshold,” Behavioral Ecology and Sociobiology 29:177—87.

House Sparrow/Cowbird (Griffin 1959); Savanna Baboon (Marais 1922/1969:214-18); Kestrel (Olsen 1985). Regarding the House Sparrow/Cowbird case, a number of subsequent researchers (e.g., Selander and LaRue 1961; Rothstein 1980) have also interpreted this behavior as “aggression” or “appeasement.” Aside from the fact that the activity involving homosexual mounting is not identical to strictly “aggressive” or “preening invitation” displays in Cowbirds (cf. Laskey 1950), a “nonsexual” interpretation cannot explain why Cowbirds “tolerate” homosexual mountings from Sparrows and even actively solicit them. Moreover, the function(s) of these “head-down” displays remain controversial and speculative independent of any homosexual activity (cf. Scott and Grumstrup-Scott 1983). Specific arguments against an “aggressive” or “appeasement” interpretation of these types of behaviors (regardless of whether any same-sex mounting is involved) are presented in Verbeek, N. A. M., R. W. Butler, and H. Richardson (1981) “Interspecific Allopreening Solicitation in Female Brewer’s Blackbirds,” Condor 83:179—80. A parallel example involves Stonor (1937:88), who “reinterprets” Selous’s (1906—7) early descriptions of homosexual mountings by female Ruffs as involving heterosexual activity by “female-plumaged” males. More recent observers (e.g., Hogan-Warburg 1966, van Rhijn 1991) have corroborated Selous’s original observations, confirming not only the existence of both female and male homosexual activity, but also “female plumaged” males (i,e., the so-called naked-nape males) that participate in homosexuality.

Chaffinch (Marjakangas 1981); Regent Bowerbird (Phillipps 1905; Marshall 1954). Similarly, early reports of courtship activity between male Swallow-tailed Manakins by Sick (1959, 1967) were discounted by Foster (1981:174), who tried to claim that the younger male birds being courted by adult males were actually females that had malelike plumage or were male observers or participants in nonsexual aggressive displays. However, Sick (1959:286) verified the male sex of these birds by dissecting them, and he stated explicitly (Sick 1967:17) that no aggression was involved in the displays. Moreover, it is clear from his descriptions (Sick 1959:286) that the display type that Foster (1981) claimed was aggressive occurs in the absence of younger males, not in their presence. Foster’s categorization of such displays as aggressive also appears to be based primarily on the fact that they occur between males, rather than on any inherent differences in the behaviors: as Foster (1981:172; 1984:58) admits, such displays are “extremely similar to” and “strongly reminiscent” of courtship behaviors. That Foster was unable to directly observe courtship displays of the type that Sick reported between males may also be due to geographic or subspecies differences in behaviors: Sick studied a population in Brazil while Foster observed birds in Paraguay. Other elements of the courtship displays between the two populations do appear to differ significantly, such as the vocalizations used and the direction in which males fly during the display (in Brazil, the male farthest from the courted bird begins the courtship “wheel,” while in Paraguay the bird closest to the courted bird begins). It should also be pointed out that Snow (1963) independently observed courtship between males in the closely related Blue-backed Manakin.

Vasey “Homosexual Behavior in Primates,” p. 197; for a similar observation, see Wolfe, “Human Evolution and the Sexual Behavior of Female Primates,” p. 130.

Hyde, H. M. (1970) The Love That Dared Not Speak Its Name: A Candid History of Homosexuality in Britain, p. 1 (Boston: Little, Brown and Company).

Killer Whale (Balcomb et al. 1979:23); published version: Balcomb, K. C., III, J. R. Boran, R. W. Osborne, and N. J. Haenel (1980) “Observations of Killer Whales (Orcinus orca) in Greater Puget Sound, State of Washington,” report no. MMC-78/13 to U.S. Marine Mammal Commission, NTIS# PB80-224728. (Washington, D.C.: U.S. Department of Commerce).

Musk-ox (Smith 1976; Tener 1965; Reinhardt 1985); Walrus (Miller 1976); Harbor Seal (Johnson 1974, 1976; Johnson and Johnson 1977).

Halls, L. K., ed., (1984) White-tailed Deer: Ecology and Management (Harrisburg, Pa.: Stackpole Books); Gerlach, D., S. Atwater, and J. Schnell, eds., (1994) Deer (Mechanicsburg, Pa.: Stackpole Books); Jones, M. L., S. L. Swartz, and S. Leatherwood, eds., (1984) The Gray Whale, Eschrictius robustus (Orlando: Academic Press). In contrast, a similarly comprehensive book on Mule Deer does mention homosexual activity (Geist 1981), as does another volume on White-tailed Deer (Rue 1989).

Woodpeckers (Short 1982; Winkler et al. 1995); Skutch, A. F. (1985) Life of the Woodpecker, p. 44 (Santa Monica: Ibis Publishing). For a similar omission of all information on homosexuality in Parrots by the standard “comprehensive” guide to this bird family, see Forshaw (1989).

See, for example, Fay (1982) on Walruses, Birkhead (1991) on Magpies, Lowther and Cink (1992) on House Sparrows, Davis (1993) on Black-crowned Night Herons, Lowther (1993) on Brown-headed Cowbirds, Telfair (1994) on Cattle Egrets, Burger (1996) on Laughing Gulls, Russell (1996) on Anna’s Hummingbirds, and Ciaranca et al. (1997) on Mute Swans.

Hooded Warbler (Niven 1993:190); Antbirds (Willis 1967, 1972, 1973); Orange-fronted Parakeet (Buchanan 1966); Golden Plover (Nethersole-Thompson and Nethersole-Thompson 1961, 1986); Mallard Duck (Lebret 1961); Black Swan (Braithwaite 1970, 1981); Scottish Crossbill (Nethersole-Thompson 1975); Black-billed Magpie (Baeyens 1981a); Pied Kingfisher (Moynihan 1990). Similar statements have been made by Konrad Lorenz (1991:241 [Greylag Goose]), who claimed that long-term pair-bonding between males only occurs in Geese and Ducks; and Hunt and Hunt (1977:1467 [Western Gull]), who were unaware of any previous reports of homosexual pairing in wild birds.

Black-headed Gull (van Rhijn and Groothuis 1985:165; Kharitonov and Zubakin 1984); Adelie Penguin (Davis et al. 1998:136); Humboldt Penguin (Scholten 1992:8); Kestrel (Olsen 452). Similar statements have been issued by scientists studying other species—Sylvestre (1985:64), for example, reported not being aware of any previous records of homosexual activity in Botos, even though fairly extensive descriptions were available in Layne and Caldwell (1964), Caldwell et al. (1966), Spotte (1967), and Pilleri et al. (1980). Walther (1990:308) claimed that courtship betweeen male hoofed mammals had not been observed in the wild, when in fact such behavior had been reported in numerous prior studies, including in Pronghorn, Blackbuck, Mountain Sheep (Bighorn, Thinhorn, Asiatic Mouflon), Mountain Goats, Musk-oxen, Bharal, and Markhor (Walther, F. R. [1990] “Bovids: Introduction,” in Grzimek’s Encyclopedia of Mammals, vol. 5, pp. 290—324 [New York: McGraw-Hill]).

See, for example, Takahata et al. (1996:149), who ask, “Is GG-rubbing a sexual behavior?” and conclude that its “nonsexual” aspects are more prominent, because of its association with tension reduction, feeding, reassurance, participation by nonestrous females, and the fact that Bonobos (unlike Japanese Macaques) do not form “exclusive homosexual female-female pairs.” None of these characteristics, in fact, negate a fully “sexual” interpretation. In particular, the fact that Bonobos do not form same-sex pairs or consortships hardly argues against the sexual nature of their genital rubbing—it simply indicates that homosexual interactions in this species do not involve extensive pair-bonding. By these criteria, Bonobo heterosexual interactions would have to be considered nonsexual as well, since they are often associated with the same “social” or “nonsexual” situations, nor do individuals form “exclusive heterosexual male-female pairs.” See also Kuroda (1980:190), who considers genital rubbing between females to be “uninterpretable” when it occurs in contexts that are not related to tension reduction or food exchange; and Kano (1980:253—54, 1992:139,1990:66—67, 69), who classifies same-sex activities in Bonobos as primarily “social” rather than “sexual” and ascribes to them the primary “functions” of greeting, reassurance, reconciliation, and food-sharing (while nevertheless recognizing that sexual aspects may be secondarily involved in some cases). As recently as 1997, researchers were still speculating about, and emphasizing, the nonsexual “functions” of Bonobo homosexual activity (Hohmann and Fruth 1997).

Mountain Sheep (Geist 1975:97—98).

Vasey, P. L. (1997, August 19) “Summary: Homosexual or Dominance Behavior? (Discussion),” message posted to Primate Talk (on-line discussion list).

Rhesus Macaque (Hamilton 1914). A standard and widely cited exposition of the dominance interpretation is Wickler, W. (1967) “Socio-sexual Signals and Their Intra-specific Imitation Among Primates,” in D. Morris, ed., Primate Ethology, pp. 69-147 (London: Weidenfield and Nicolson).

On the occurrence of dominance hierarchies in various mammals and birds without homosexuality, and further references, see Wilson, E. O. (1975) Sociobiology: The New Synthesis, p. 283 (Cambridge and London: Belknap Press); Welty, J. C., and L. Baptista (1988) The Life of Birds, 4th ed., pp. 206-210 (New York: W. B. Saunders).

For explicit statements on the absence, unimportance, or irrelevance of dominance hierarchies in these species or populations, see Gorilla (Yamagiwa 1987a:25; Robbins 1996:957); Savanna (Olive) Baboon (Rowell 1967b:507-8); Bottlenose Dolphin (Shane et al. 1986:42); Zebras (Penzhorn 1984:113; Schilder 1988:300); Musk-ox (Smith 1976:92-93); Koala (Smith 1980:187); Buff-breasted Sandpiper (Lanctot and Laredo 1992:7); Tree Swallow (Lombardo et al. 1994:556). In Gorilla all-male groups, dominance is not a central organizing feature of social interactions (including homosexual interactions) even though some semblance of a dominance “hierarchy” may exist and males clearly have different ranks. The same may also be true for Hanuman Langur all-male groups (Weber and Vogel 1970:75) and Collared Peccary mixed-sex groups (Sowls 1997:151-53) in which same-sex interactions occur. In Buff-breasted Sandpipers, although mounting between males may be accompanied by aggression and therefore superficially appears related to “dominance,” there is in fact no evidence that a dominance hierarchy exists in this species or constitutes an important aspect of its social organization. In some of these species (e.g., Zebras, Musk-oxen, Bottlenose Dolphins) dominance hierarchies are more prominent in captivity, although homosexual activity occurs in both wild and captive contexts. Finally, J. Steenberg (personal communication) suggests that mounting between female Matschie’s Tree Kangaroos is a dominance display, yet Hutchins et al. (1991:154-56, 161) found no clear-cut dominance hierarchy in the study population where this behavior was observed.

Tasmanian Native Hen (Ridpath 1972:81) (in this species, hierarchies can be induced in wild birds by provisioning them with food, but dominance plays no role in their unprovisioned activities—including homosexual mounting, which is not associated in any way with induced dominance); Little Blue Heron (Werschkul 1982:383-84); white-browed sparrow weaver and other weavers (Collias, N. E., and E. C. Collias [1978] “Cooperative Breeding Behavior in the White-browed Sparrow Weaver,” Auk 95:472-84; Collias, N. E., and E. C. Collias [1978] “Group Territory, Dominance Hierarchy, Co-operative Breeding in Birds, and a New Factor,” Animal Behavior 26:308—9). Likewise, dominance systems occur in most Macaques, yet homosexual behavior is apparently absent in some species, e.g., the Barbary Macaque (Macaca sylvanus)—see Vasey, “Homosexual Behavior in Primates,” pp. 178-79; for an extensive summary of research on this species with no mention of same-sex mounting, see Fa, J. E., ed. (1984) The Barbary Macaque: A Case Study in Conservation (New York: Plenum Press). However, recent work seems to suggest that same-sex mounting may in fact occur: Di Trani, C. M. P. (1998) “Conflict Causes and Resolution in Semi-Free-Ranging Barbary Macaques (Macaca sylvanus ),” Folia Primatologica 69:47-48. Therefore, this example must be interpreted with caution, like many other instances involving an apparent “absence” of homosexual behavior (see chapter 4 for further discussion).

Wolf (Zimen 1976, 1981); Spotted Hyena (Frank 1986); Squirrel Monkey (Baldwin and Baldwin 1981:294—95; Castell and Heinrich 1971:187-88); Bottlenose Dolphin (Samuels and Gifford 1997:82, 88—90). In Red Squirrels, both sexes have dominance systems yet same-sex mounting is much more prominent among males (Ferron 1980:135—36); in Bonobos, a dominance system is much more developed or important among males (de Waal 1997:72—74), yet homosexual activities occur in both sexes. A related observation is that in Bighorn Sheep, both sexes have well-defined dominance systems and exhibit same-sex mounting, yet only among males does it have some correlation with homosexual activity.

For examples of animals that participate in interspecies homosexual mounting, see the profiles for Crabeating Macaque, Bottlenose Dolphin, Walrus, Greenshank, Orange Bishop Bird, and House Sparrow. On the occurrence of interspecies dominance hierarchies, see, for example, Fisler, G. F. (1977) “Interspecific Hierarchy at an Artificial Food Source,” Animal Behavior 25:240-44; Morse, D. H. (1974) “Niche Breadth as a Function of Social Dominance,” American Naturalist 108:818-30.

Rhesus Macaque (Reinhardt et al. 1986:56); Japanese Macaque (Chapais and Mignault 1991:175-76; Vasey et al. 1998); Common Chimpanzee (Nishida and Hosaka 1996:122 [table 9.7]). See also Bygott 1974—cited in Hanby 1974:845 [Japanese Macaque]—who found that 59 percent of mounts between male Chimps were by subordinates on dominants or by equally ranked participants.

Musk-ox (Reinhardt 1985:298). In Cattle Egrets, Fujioka and Yamagishi (1981:139) stated that males attempting homosexual copulations always rank higher than or equal to the males they mount. Yet two males in their study population who mounted other males were apparently not part of the dominance hierarchy (cf. their table 3), while the highest-ranking male did not participate in any same-sex mounts. M. Fujioka (personal communication) concedes that the rank of the males may not actually be an important factor in their homosexual mounting.

Crested Black Macaque (Dixson 1977:77; Poirier 1964:96); American Bison (Reinhardt 1985:218, 222, 1987:8); Pig-tailed Macaque (Oi 1990a:350); Red Deer (Hall 1983:278); Pukeko (Jamieson and Craig 1987b:319-22); Japanese Macaque (Chapais and Mignault 1991:175-76); Bighorn Sheep (Shackleton 1991:179-80).

A further argument is provided by “pile-up mounts,” i.e., when three individuals are all mounted (stacked) on each other. In this case, the mounter-mountee relations rarely if ever follow dominance lines: either they occur in species without dominance hierarchies (e.g., Sage Grouse, Common Murre), or else it is not the case that the middle animal is both higher-ranking than the animal it is mounting but lower-ranking than the animal who is mounting it (e.g., Wolf, Bonobo). For more on pile-up mounts, see chapter 4.

Common Chimpanzee (Nishida and Hosaka 1996:122; Bygott 1974 [cited in Hanby 1974:845 (Japanese Macaque)]); White-faced Capuchin (Manson et al. 1997:771, 780); Blackbuck (Dubost and Feer 1981:89— 90); Cavies (Rood 1972:36); Gray-capped Social Weaver (Collias and Collias 1980:218, 220). Although mounting between male Musk-oxen in captivity seems to follow dominance lines (Reinhardt 1985), in wild herds Smith (1976) found no dominance hierarchy within (as opposed to between) sex/age classes. Same-sex mounting in the wild occurs among age-mates (who are therefore essentially equal in rank, e.g., two-year-old males mount each other).

See, for example, Bertrand 1969:191 (Stumptail Macaque); Simonds 1965:183, Sugiyama 1971:259 (Bonnet Macaque); Bernstein 1972:406 (Pig-tailed Macaque); Dixson et al. 1975:195-96 (Talapoin Monkey); Kaufmann 1974:309 (Whiptail Wallaby).

A distinction between consensual and nonconsensual homosexual mounts is found in more than 30 different species of mammals and birds. Direct evidence of sexual arousal and stimulation on the part of animals being mounted is also available in many species, including orgasmic (and other) responses in female Japanese, Rhesus, Stumptail, and Pig-tailed Macaques being mounted; erection and masturbation by male mountee Rhesus, Pig-tailed, and Crested Black Macaques; thrusting by male Bonobos being mounted; and stimulation of the mountee’s clitoris by her partner’s thrusting in Hanuman Langurs and Japanese Macaques. In addition to direct and indirect genital stimulation during mounting, it is quite likely that male animals being penetrated during anal intercourse also experience stimulation of the prostate gland (which presses against the wall of the rectum). In human males, direct stimulation of the prostate—for instance, during anal intercourse—can be highly arousing and may precipitate or enhance orgasm. A similar capacity is probably present in all male mammals. Although direct evidence (in the form of firsthand accounts) of the pleasurable or arousing nature of this activity is, of course, lacking in nonhuman animals, there is some indirect evidence. A standard technique of inducing erection and ejaculation (for purposes of artificial insemination) in male mammals is through anal and/or prostate stimulation. Known as electroejaculation, this technique involves insertion of an anal probe and stimulation of the rectum—especially in the area of the prostate gland—with a mild electrical current as well as back-and-forth (thrusting) movements of the probe. This technique has proven effective in numerous species of mammals, including virtually all of those in which male homosexual mounting and /or anal penetration occur. For further information on electroejaculation, see Watson, P. F., ed. (1978) Artificial Breeding of Non-Domestic Animals, Symposia of the Zoological Society of London no. 43, especially pp. 109, 129, 208—10, 221, 295 (London: Academic Press).

Hanuman Langur (Srivastava et al. 1991:506–7); for a similar assessment with regard to homosexual activity between males in this species, see Weber and Vogel (1970:77–78). See also Rowell (1967a:23), who states that “sexual” and “dominance” mounts in Savanna (Yellow) Baboons are virtually indistinguishable, and Enomoto (1990:473), who remarks on the difficulty of discriminating between sexual and ritualized dominance mounting in Bonobos because of the gradation between the two. Weinrich (Sexual Landscapes, p. 294), in discussing mounting between male Mountain Sheep, also points out how sexuality and dominance can both be part of the same behavior and suggests an analogy with human sexuality. Indeed, elements of consensual “dominance” or power-play, although rarely acknowledged, are often a part of human lovemaking and sexual pleasure, ranging along a continuum from gentle “love bites” to full sadomasochism (and nonconsensual dominance also figures prominently in many human sexual interactions, especially heterosexual ones).

Japanese Macaque (Wolfe 1986:268); Rhesus Macaque (Akers and Conaway 1979:78); Greylag Goose (Lorenz 1991:206); Black-winged Stilt (Kitagawa 1989:65, 69) (see also the distinction between same-sex courtship and aggressive/appeasing kantling in Ostriches [Sauer 1972:731; Bertram 1992:15, 50–51]). For species such as these that have a clear distinction between mounts in sexual and nonsexual contexts, only the former are considered (in this book and in most sources) to be homosexual behavior. As noted in chapter 1, some species classified by Dagg (1984) as exhibiting homosexuality (e.g., bush squirrels and degus) are excluded from our roster on the basis of this criterion, because all same-sex mounting in these species appears to fall into this genuinely nonsexual category; see Viljoen, S. (1977) “Behavior of the Bush Squirrel, Paraxerus cepapi cepapi,” Mammalia 41:119—66; Fulk, G. W. (1976) “Notes on the Activity, Reproduction, and Social Behavior of Octodon degus,” Journal of Mammology 57:495–505.

Walrus (Miller 1975:607); Gray Seal (Anderson and Fedak 1985); Oystercatcher (Ens, B. J., and J. D. Goss-Custard [1986] “Piping as a Display of Dominance by Wintering Oystercatchers Haematopus ostralegus,” Ibis 128:382—91). Early observers of this species (e.g., Makkink 1942) misinterpreted the piping display as a courtship activity because it often occurs between males and females.

For details of the way that dominance is expressed in these species, see Savanna (Yellow) Baboon (Maxim and Buettner-Janusch 1963:169); Hamadryas Baboon (Stammbach, E. [1978] “On Social Differentiation in Groups of Captive Female Hamadryas Baboons,” Behavior 67:322-38); Bottlenose Dolphin (Samuels and Gifford 1997); Killer Whale (Rose 1992:108-9); Caribou (Espmark, J. [1964] “Studies in Dominance-Subordination Relationship in a Group of Semi-Domestic Reindeer (Rangifer tarandus L.),” Animal Behavior 12:420-26); Blackbuck (Dubost and Feer 1981:97-100); Wolf (Zimen 1976, 1981); Bush Dog (Macdonald 1996); Spotted Hyena (Frank 1986:1511); Grizzly Bear (Craighead et al. 1995:109ff); Black Bear (Stonorov and Stokes 1972:235, 242); Red-necked Wallaby (Johnson 1989:267); Canada Goose (Collias and Jahn 1959:500-501); Scottish Crossbill (Nethersole-Thompson 1975:53); Black-billed Magpie (Birkhead 1991); Jackdaw (Roell 1978); Acorn Woodpecker (Stanback 1994); Galah (Rowley 1990:57). In Pronghorns, mounting between males was originally claimed to represent a dominance activity (Kitchen 1974), yet more recent studies of dominance in this species have not included same-sex mounting (Bromley 1991).

In some cases, sexual behaviors other than mounting can be correlated with dominance. For example, grooming between males in Nilgiri Langurs and Crested Black Macaques is often performed by a subordinate animal on a more dominant one. Nevertheless, it is apparent that this activity has a clearly sexual component as well: one or both males may become intensely aroused, developing an erection and even ejaculating during the grooming (see Poirier 1970a:334 for Nilgiri Langurs and Poirier 1964:146—47 for Crested Black Macaques). Similarly, adult (dominant) Bonobos often masturbate or massage the genitals of adolescent (subordinate) males, but again, the activity involves clear sexual stimulation (cf. de Waal 1987, 1995, 1997). Also, Squirrel Monkey genital displays are sometimes correlated with dominance, but there are also cases where the association is less than definitive, or where they occur in clearly sexual contexts between animals of the same sex (cf. Talmage-Riggs and Anschel 1973:70; Travis and Holmes 1974:55; Baldwin and Baldwin 1981:295-97; Castell and Heinrich 1971:187-88).

One cannot help but surmise that it is the heterosexism of many biologists that has led them to focus on mounting behavior to the exclusion of other activities in their appeal to dominance factors—for only in mounting can the positions of the participants be clearly analogized to those of a male and female in a heterosexual interaction. As Fedigan (1982:101 [Japanese Macaque]) points out, underlying the entire discussion of dominance in same-sex interactions is the assumption that homosexual mounting is essentially a transposition from heterosexual copulation—and that males “dominate” females in such interactions. For further evidence against this view, see the discussion of homosexuality as a form of “pseudoheterosexuality” in chapter 4.

Possible exceptions are same-sex courtship interactions in Mountain Sheep (Geist 1968, 1971), Musk-oxen (Reinhardt 1985), and Cavies (Rood 1972), which have been interpreted as reflecting dominance. Additionally, mounting or other sexual behaviors within a same-sex pair-bond—common in many bird species—does not fit easily into a dominance interpretation, since this usually involves ongoing interaction with only one other animal (rather than the establishment of hierarchical positions within a network of individuals).

Giraffe (Pratt and Anderson 1985:774—75, 780—81); Crested Black Macaque (Dixson 1977:77-78; Reed et al. 1997:255); Stumptail Macaque (Bernstein 1980:40); Pig-tailed Macaque (Giacoma and Messeri 1992:187); Savanna (Olive) Baboon (Owens 1976:250-51); Squirrel Monkey (Baldwin and Baldwin 1981:295-97; Baldwin 1968:296, 311); Red Squirrel (Ferron 1980:136); Spinifex Hopping Mouse (Happold 1976:147); American Bison (Reinhardt 1985:222-23); Pukeko (Lambert et al. 1994); Sociable Weaver (Collias and Collias 1980:246, 248; in the latter instance, the inconsistency in dominance status was not one of the cases of temporary reversals of dominance that were occasionally seen in this species). In female Squirrel Monkeys, dominance hierarchies are not considered to be a salient feature of social organization in the wild (Baldwin and Baldwin 1981:294-95). However, even when dominance systems appear to develop (e.g., in some captive situations), investigators have found that the rank of females based on their homosexual activities does not agree with other measures of rank (Anschel and Talmage-Riggs 1978:602 [table 1]).

For some reevaluation and/or critiques of the concept of dominance, see Gartlan, J. S. (1968) “Structure and Function in Primate Society,” Folia Primatologica 8:89-120; Bernstein 1970 (Crab-eating Macaque); Richards, S. M. (1974) “The Concept of Dominance and Methods of Assessment,” Animal Behavior 22:914— 30; Ralls, K. (1976) “Mammals in Which Females Are Larger Than Males,” Quarterly Review of Biology 51:245-76; Lockwood, R. (1979) “Dominance in Wolves: Useful Construct or Bad Habit?” in E. Klingham-mer, ed., Behavior and Ecology of Wolves, pp. 225-44 (New York: Garland); Baldwin and Baldwin 1981 (Squirrel Monkey); Bernstein, I. S. (1981) “Dominance: The Baby and the Bathwater,” Behavioral and Brain Sciences 4:419-57; Hand, J. L. (1986) “Resolution of Social Conflicts: Dominance, Egalitarianism, Spheres of Dominance, and Game Theory,” Quarterly Review of Biology 61:201-20; Walters, J. R., and R. M. Seyfarth (1987) “Conflict and Cooperation,” in B. B. Smuts, D. L. Cheney, R. M. Seyfarth, R. W. Wrangham, and T. T. Struhsaker, eds., Primate Societies, pp. 306-17 (Chicago and London: University of Chicago Press); Drews, C. (1993) “The Concept and Definition of Dominance in Animal Behavior,” Behavior 125:283-313; Lambert et al. 1994 (Pukeko).

Fedigan 1982:92-93 (Japanese Macaque).

Bonobo (Kano 1992:253-54; Kitamura 1989:57, 63); Gorilla (Harcourt et al. 1981:276; Yamagiwa 1987a:25; Harcourt 1988:59); Hanuman Langur (J. J. Moore, in Weinrich 1980:292); Japanese Macaque (Vasey 1996:549; Chapais and Mignault 1991:175-76; Tartabini 1978:433, 435; Hanby 1974:841); Rhesus Macaque (Akers and Conaway 1979:78; Reinhardt et al. 1986:55; Gordon and Bernstein 1973:224); Pig-tailed Macaque (Tokuda et al. 1968:293); Crested Black Macaque (Dixson 1977:77-78; Poirier 1964:20, 49; Reed et al. 1997:255); Savanna Baboon (Owens 1976:256); Gelada Baboon (Mori 1979:134-35; R.Wrangham, in Weinrich 1980:291); Squirrel Monkey (Talmage-Riggs and Anschel 1973:70); Bottlenose Dolphin (Caldwell and Caldwell 1972:427); Blackbuck (Dubost and Feer 1981:89-90); Giraffe (Pratt and Anderson 1985:774— 75, 780); American Bison (Reinhardt 1985:222, 1987:8); Red Squirrel (Ferron 1980:136); Little Blue Heron (Werschkul 1982:383-84); Tree Swallow (Lombardo et al. 1994:556).

For examples of earlier claims of a dominance connection being refuted by later studies, see Common Chimpanzee (Yerkes 1939:126-27; Nishida 1970:57—Bygott 1974 [cited in Hanby 1974:845 (Japanese Macaque)]; Nishida and Hosaka 1996:122 [table 9.7]); Hanuman Langur (Weber 1973:484—Srivastava et al. 1991:506— 7; J. J. Moore, in Weinrich 1980:292); Rhesus Macaque (Carpenter 1942—Akers and Conaway 1979:78; Reinhardt et al. 1986; Gordon and Bernstein 1973:224); Japanese Macaque (Sugiyama 1960:136—Hanby 1974:841; Chapais and Mignault 1991:175-76); Bonnet Macaque (Rahaman and Parthasarathy 1968:68, 263—Makwana 1980:10); Pig-tailed Macaque (Tokuda et al. 1968—Oi 1990a:353-54); Killer Whale (Balcomb et al. 1979:23—Rose 1992:108-9); Giraffe (Dagg and Foster 1976, Leuthold 1979:27—29—Pratt and Anderson 1985:774-75); Blackbuck (Schaller 1967—Dubost and Feer 1981:89—90); American Bison (Lott 1974:391—Reinhardt 1986:222-23); Wolf (Schenkel 1947—van Hooff and Wensing 1987:232). In addition, a parallel example in Laughing Gulls involves an indirect refutation of the relevance of dominance. Noble and Wurm (1943:205-6) linked homosexual mounting in Laughing Gulls to the supposedly lower rank of the male being mounted, citing as evidence of his lower status the fact that the mounted male did not “dominate” his female mate. In a more recent detailed study of interactions between partners in heterosexual pairs, however, Hand (1985) concluded that males do not in general dominate their female mates in this species—thus invalidating the earlier claim that being mounted homosexually was correlated with “lower status.” Studies that attribute homosexual activity to dominance with little or no supporting evidence include Orang-utan (Rijksen 1978:257); Squirrel Monkey (DuMond 1968:124); West Indian Manatee (Rathbun et al. 1995:150); Pied Kingfisher (Moynihan 1990:19).

Whiptail Wallaby (Kaufmann 1974:307, 309); Rhesus Macaque (Gordon and Bernstein 1973:224). Kaufmann concluded that Whiptail Wallaby homosexual mountings are themselves probably not dominance-related, however, because dominant animals generally invite subordinate ones to mount (the opposite of the “usual” dominance pattern).

Bighorn Sheep (Hogg 1987:120; Hass and Jenni 1991:471); Crested Black Macaque (Poirier 1964:54).

Vasey, “Homosexual Behavior in Primates,” p. 191.

100

Orang-utan (Maple 1980:118).

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West Indian Manatee (Rathbun et al. 1995:150). See also the suggestion in Buss (1990:19-21) that sexual arousal in male African Elephants during same-sex play-fighting serves to dull pain. While this is possible, it is rather far-fetched, considering that such ritual fights (described by Buss as “erotic”) are rarely violent.

102

Vasey, P. L. (in press) “Homosexual Behavior in Male Birds,” in W. R. Dynes, ed., Encyclopedia of Homosexuality, 2nd ed., vol. 1: Male Homosexuality (New York: Garland Press).

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American Bison (Reinhardt 1985:222) (cf. also Kaufmann [1974:107] on Whiptail Wallabies, who asserts, “Though tail-lashing seems clearly a sign of sexual arousal, it was occasionally performed by males when they were approached by subordinate males in nonsexual situations”); Asiatic Mouflon (McClelland 1991:80); Stumptail Macaque (O’Keefe and Lifshitz 1985:149); Dugong (Nair et al. 1975:14); Laysan Albatross (Frings and Frings 1961:311); Dwarf Mongoose (Rasa 1979a:365); Bonnet Macaque (Nolte 1955:179). Similarly, Frank et al. (1990:308) state that genital erections in Spotted Hyenas have no “sexual significance” unless displayed by a male toward a female during courtship. The “desexing” of this behavior stems, in large part, from the fact that erections are frequently displayed between animals of the same sex (especially females) and in situations that do not involve (heterosexual) mounting (e.g., during the “meeting ceremony”). While erections undoubtedly have “nonsexual” connotations outside of a mounting context (see, for example, East et al. 1993), it seems overly restrictive to eliminate all “sexual significance” from situations that do not fall into the category of heterosexual courtship and mating.

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Redshank (Hale and Ashcroft 1983:21). For a summary of the historical interpretation of this behavior, see also Cramp and Simmons 1983:533.

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Crested Black Macaque (Dixson 1977:71, 76; Poirier 1964:147). Dixson (1977:77) does concede that the distinction between sexual and nonsexual mounts and solicitations is a subjective one, but only in heterosexual contexts—homosexual interactions are assumed to be self-evidently nonsexual.

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Vicuna (Koford 1957:183, 184); Musk-ox (Smith 1976:51); Giraffe (Dagg and Foster 1976:127; Pratt and Anderson 1985:777-78; Leuthold 1979:27, 29); Bank Swallow (Beecher and Beecher 1979:1284); Savanna Baboon (Smuts 1985:18, 148—49, 163-66, 199, 213); Rhesus Macaque (Loy 1971:26); Oystercatcher (Makkink 1942; Ens and Goss-Custard, “Piping as a Display of Dominance”).

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Crested Black Macaque (Dixson 1977:70—71); Bottlenose Dolphin (Ostman 1991:313; Dudok van Heel and Mettivier 1974:12; Saayman and Tayler 1973); Spinner Dolphin (Norris and Dohl 1980a:845; Norris et al. 1994:199); Common Murre (Birkhead 1978a:326); Blue-bellied Roller (Moynihan 1990).

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Rhesus Macaque (see, for example, Sade 1968:32-33); Japanese Macaque (Hanby 1974:843, 845; Wolfe, “Human Evolution and the Sexual Behavior of Female Primates,” p. 129).

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For further discussion see chapter 5. On a related point, aggressive behaviors may accompany homosexual interactions in some species and are therefore used to argue that such behavior is not “really” sexual. However, aggression is also characteristic of heterosexual relations in many species, where such male-female interactions are still classified as “sexual.”

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Kob (Buechner and Schloeth 1965:218); Giraffe (Pratt and Anderson 1985:774-75); northern jacana (del Hoyo, J., A. Elliott, and J. Sargatal, eds. [1996] Handbook of the Birds of the World, vol. 3: Hoatzin to Auks, p. 282. [Barcelona: Lynx Edicións]); Orang-utan (Galdikas 1981:286).

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Walrus (Dittrich 1987:168); Musk-ox (Smith 1976:62); Bighorn Sheep (Hogg 1984:527; Geist 1971:139); Asiatic Mouflon (McClelland 1991:81); Grizzly Bear (Craighead et al. 1995:161); Olympic Marmot (Barash 1973:212); White-tailed Deer (Hirth 1977:43); Orang-utan (Galdikas 1981:286); White-faced Capuchin (Manson et al. 1997:775); Northern Fur Seal (Gentry 1998:172); Ruff (Hogan-Warburg 1966:167-68). Additionally, in one study of Matschie’s Tree Kangaroos—a species in which researchers deny that mounting between females is (homo)sexual (J. Steenberg, personal communication)—all mounts observed between animals of the opposite sex were “incomplete” in that they did not involve penetration or thrusting (Hutchins et al. 1991:158). Another study of the same population found both that “full” copulations between males and females were infrequent, and that in heterosexual contexts females showed few overt signs of sexual interest, since the behavioral cues for female sexual arousal are extremely subtle (Dabek 1994:84, 93—94, 116).

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Morrill and Robertson 1990 (Tree Swallow); Scott, M. P., and T. N. Tan (1985) “A Radiotracer Technique for the Determination of Male Mating Success in Natural Populations,” Behavioral Ecology and Sociobiology 17:29-33. More recently, a copulation-verification technique using fluorescent powder has been tested for rodents. Dusted on males, the powder is transferred to females during mating and can be checked using ultraviolet light. Ironically, during the testing of this procedure, pairs of females were used as “controls” since it was assumed that they would not engage in mounting behavior with one another. Nevertheless, 12 percent of female pairs showed transfer of powder—but of course this was interpreted by researchers as evidence of nonsexual contact between such females (Ebensperger, L. A., and R. H. Tamarin [1997] “Use of Fluorescent Powder to Infer Mating Activity of Male Rodents,” Journal of Mammalogy 78:888-93).

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Rhesus Macaque (Erwin and Maple 1976); field report of penetration and ejaculation (Sade 1968:27); see also Kempf (1917:134) for an even earlier documentation of anal penetration between (captive) male Rhesus Macaques. Walther (1990:308) makes a parallel claim that mounting activity between male hoofed mammals does not constitute (homo)sexual behavior because erection and anal penetration are not always observed (Walther, “Bovids: Introduction”). On a related point, Tuttle (1986:289) takes great pains to point out that rump-rubbing and mounting between male Bonobos do not “qualify” as genital contact because, “pace certain sodomites, the anus is not a genital organ (International Anatomical Nomenclature Commitee, 1977, p. A49).” Tuttle does, however, accept that sexual activity between females—which he calls “bizarre homosexual hunching” (ibid., p. 282)—qualifies as genital contact (Tuttle, R. H. [1986] Apes of the World: Their Social Behavior, Communication, Mentality, and Ecology [Park Ridge, N.J.: Noyes Publications]). For a recent survey of homosexual behavior in primates that (wisely) drops the occurrence of penetration, arousal, and/or orgasm as a defining criterion of the behavior, see Vasey, “Homosexual Behavior in Primates,” p. 175.

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On a similar gradation of mounting behavior in male birds, see Moynihan 1955:105 (Black-headed Gull).

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For specific arguments against homosexual activity as a form of tension reduction in various species, see Yamagiwa 1987a:23, 1987b:37 (Gorilla); Edwards and Todd 1991:234-35 (White-handed Gibbon); Vasey 1996:549-50 (Japanese Macaque); R. Wrangham, in Weinrich 1980:291 (Gelada Baboon). Against homosexuality as a form of play, see Talmage-Riggs and Anschel 1973:71 (Squirrel Monkey); Lombardo et al. 1994:556 (Tree Swallow). Against homosexuality as reconciliation or reassurance behavior, see Vasey 1996:550 (Japanese Macaque); Akers and Conaway 1979:78 (Rhesus Macaque); Lombardo et al. 1994:556 (Tree Swallow). Against homosexual activities as a means of forging coalitions or alliances, see Silk 1994:285—87 (Bonnet Macaque) (and also Silk 1993:187 for arguments that coalition-bonding between males in this species is not “functional” in terms of enhancing the males’ status, access to resources, or inclusive fitness). Against homosexuality as a gesture of appeasement or placation, see Manson et al. 1997:783 (White-faced Capuchin); Ferron 1980:136 (Red Squirrel); Lombardo et al. 1994:556 (Tree Swallow). Against homosexual relations as “kinship alliances” between individuals who associate with each other primarily because they are related (so-called kin selection), see Fernández and Reboreda 1995:323 (Greater Rhea); Heg and van Treuren 1998:688-89, Ens 1998:635 (Oystercatcher); Afton 1993:232 (Lesser Scaup Duck); Rose 1992:104, 112 (Killer Whale); Hashimoto et al. 1996:316 (Bonobo). See also Vasey, “Homosexual Behavior in Primates,” for a summary and review of the evidence against many of these nonsexual “explanations.”

116

Japanese Macaque (Vasey 1996).

117

Bonobo (de Waal 1987, 1995 [among others]; Savage-Rumbaugh and Lewin 1994:110); Gorilla (Yamagiwa 1987a:23, 1987b:37).

118

See Silk 1994:285-87 (Bonnet Macaque) for more detailed discussion.

119

Signs of sexual arousal such as these have been documented for homosexual interactions in more than 90 species of mammals and birds. In addition, a number of scientists have themselves asserted the clearly sexual character of same-sex interactions (in addition to, or instead of, nonsexual aspects); see, for example, de Waal 1995:45—46 (Bonobo); Yamagiwa 1987a, Harcourt 1988:59, Porton and White 1996:724 (Gorilla); Edwards and Todd 1991 (White-handed Gibbon); Weber and Vogel 1970:76-77 (Hanuman Langur); Vasey 1996:550, Rendall and Taylor 1991:324, Wolfe 1984:147 (Japanese Macaque); Akers and Conaway 1979:78-79 (Rhesus Macaque); Chevalier-Skolnikoff 1976:525 (Stumptail Macaque); Srivastava et al. 1991 (Hanuman Langur); R. Wrangham, in Weinrich 1980:291 (Gelada Baboon); Manson et al. 1997:775-76 (White-faced Capuchin); Herzing and Johnson 1997:85, 90 (Bottlenose/Atlantic Spotted Dolphins); Saulitis 1993:58 (Killer Whale); Darling 1978:60, 1977:10—11 (Gray Whale); Coe 1967:320 (Giraffe); Rue 1989:313 (White-tailed Deer); Buss 1990:20 (African Elephant); Heg and van Treuren 1998:688 (Oystercatcher); Davis et al. 1998 (Adélie Penguin); Stiles 1982:216 (Anna’s Hummingbird). For use of the word erotic to characterize same-sex interactions, see, for example, de Waal 1987:323, 1997:103-4, Kano 1992:192, 1990:66 (Bonobo); Darling 1977:10—11 (Gray Whale); Mathews 1983:72 (Walrus); Buss 1990:19 (African Elephant).

120

Occasionally, however, multiple “functions” are granted to heterosexual behavior; see, for example, Lindburg 1971 (Rhesus Macaque); de Waal 1987, 1995, 1997, Kano 1990:67 (Bonobo); Manson et al. 1997 (White-faced Capuchin); Hanby, J. (1976) “Sociosexual Development in Primates,” in P. P. G. Bateson and P. H. Klopfer, eds., Perspectives in Ethology, vol. 2, pp. 1-67 (New York: Plenum Press).

Chapter 4. Explaining (Away) Animal Homosexuality

M. Grober, opening remarks to the plenary session on Sexual Orientation, 24^th International Ethological Conference, Honolulu, Hawaii, August 12, 1995.

Among the attendees who had previously documented or written extensively on animal homosexual behavior, but who were not speaking on this topic, were B. Le Boeuf (Northern Elephant Seals), C. Clark (Right Whales), W. D. Koenig (Acorn Woodpeckers), M. Moynihan (Rufous-naped Tamarins, Pied Kingfishers, Blue-bellied Rollers), A. Srivastava (Hanuman Langurs), F. B. M. de Waal (Bonobos, other primates), and J. C. Wingfield (Gulls). A number of other disconcerting trends were also in evidence among the papers presented during this symposium: for example, many were based on studies of laboratory or captive animals to the exclusion of information on homosexuality/transgender in wild animals. One presenter (Ulibarri) actually went so far as to state that no information was available in English on any behavior of wild Mongolian gerbils, when in fact at least one such study had been published several years earlier in a prominent zoology journal (Ulibarri, C. [1995] “Gonadal Steroid Regulation of Differentiation of Neuroanatomical Structures Underlying Sexual Dimorphic Behavior in Gerbils,” paper presented at the 24^th International Ethological Conference, Honolulu, Hawaii; Ågren, G., Q. Zhou, and W. Zhong [1989] “Ecology and Social Behavior of Mongolian Gerbils, Meriones unguiculatus, at Xilinhot, Inner Mongolia, China,” Animal Behavior 37:11—27).

Caprio, F. S. (1954) Female Homosexuality, pp. 19, 76 (New York: Grove); Northern Fur Seal (Bartholomew 1959:168).

This idea appears in the descriptions of homosexuality in more than 40 different species of mammals and birds.

Homosexuality and related phenomena in animals have even been labeled “heterotypical behavior” (cf. Haug, M., P. F. Brain, and C. Aron, eds., [1991] Heterotypical Behavior in Man and Animals [New York: Chapman and Hall]). The intended meaning of this term is that the behavior of at least one of the partners during same-sex interactions is supposedly “typical” of participants in heterosexual activity, but transposed onto a same-sex context—in other words homosexuality is simply recast as a modified version of heterosexuality.

Orange-fronted/Aztec Parakeets (Hardy 1966:77, 1963:171). In a related vein, the vocal and sexual responses of female Stumptail Macaques during orgasm were studied primarily in homosexual, rather than heterosexual, interactions; this information was then generalized or extrapolated to opposite-sex contexts (cf. Goldfoot et al. 1980; Leinonen et al. 1991:245). Likewise, the synchronization of pair-bonding activities in Galahs was typified in one study with quantitative information from same-sex rather than opposite-sex pairs (Rogers and McCulloch 1981:87).

Freud, S. (1905/1961) Drei Abhandlungen zur Sexualtheorie (Frankfurt: Fischer); see also Ellis, H. (1936) Sexual Inversion: Studies in the Psychology of Sex (New York: Random House).

Morris 1954 (Zebra Finch); Morris 1952 (Ten-spined Stickleback). For a more recent article, see Schlupp et al. 1992 (Amazon Molly). See also Lorenz 1972:21 (Raven) for an early (errroneous) statement to the effect that during same-sex interactions animals only exhibit “purely” masculine or feminine behaviors (as defined by a heterosexual context) rather than any intermediate forms.

Takhi (Boyd 1986:661); Mallard Duck (Ramsay 1956:277); Snow Goose (Starkey 1972). Another notable example of the conflation of “inverted” gender traits (and other “deviant” characteristics) with playing the “opposite-sex” role in homosexual interactions involves the Common Chimpanzee. A female Chimp that was apparently exclusively lesbian for many years (and consorted with otherwise “heterosexual” females) was described by a scientist—in addition to being sexually “aberrant”—as having a “burly manner,” being “masculine-looking,” “two-faced and mean,” “malevolent,” and “deceitful.” Comments from untrained observers that compared her to a witch were also repeated without qualification (de Waal 1982:64—65). While some of these traits may have reflected genuine aspects of her physical appearance, behavior, and personality, it is striking how loaded and anthropomorphic these descriptions are, and how many of the characteristics singled out for mention correspond precisely to the negative and distorted stereotypes of “butch” lesbians among humans. Moreover, in many animals, (heterosexual) females may display greater levels of aggression when they are in “heat”—one scientist even described female Chimpanzees as being “masculinized” by the onset of their estrus (Nishida 1979:103). Aside from being inappropriate in specific cases, then, it is inaccurate to ascribe greater aggression solely to “malelike” females in homosexual contexts when this may in fact be an independent feature of female sexual arousal. In addition, a recent comprehensive survey of over 700 mammal species found no correlation between the occurrence of “masculinized” female genitalia and female aggression or dominance (Teltscher, C., H. Hofer, and M. L. East [1997] “Virilized Genitalia are Not Required for the Evolution of Female Dominance,” in M. Taborsky and B. Taborsky, eds., Contributions to the XXV International Ethological Conference, p. 281, Advances in Ethology no. 32. [Berlin: Blackwell Wissenschafts-Verlag]). Incidentally, the female Chimpanzee referred to above was also nicknamed “the Madam” because of her apparent regulation of the sexual activity of other females, echoing an earlier nicknaming of an intersexual Savanna Baboon as “the Prostitute” (Marais 1922/1969:205—6). These examples offer striking parallels to the association, among humans, of female homosexuality/gender variance with prostitution. Both are seen as “deviant” activities and are linked not only in the mythic and popular imagination, but also sometimes in actual historical and social realities (cf. Nestle, J. [1987] “Lesbians and Prostitutes: A Historical Sisterhood,” in A Restricted Country, pp. 157—77 [Ithaca: Firebrand Books]; Salessi, J. [1997] “Medics, Crooks, and Tango Queens: The National Appropriation of a Gay Tango,” pp. 151, 161-62, in C. F. Delgado and J. E. Muñoz, eds., Everynight Life: Culture and Dance in Latin/o America, pp. 141—74 [Durham: Duke University Press]).

Although many zoologists have uncritically advocated such an “explanation” or interpretation of homosexuality, a few scientists have presented explicit arguments against such an analysis: Wolfe 1979:532, Lunardini 1989:183 (Japanese Macaque); Srivastava et al. 1991:506—7 (Hanuman Langur); Huber and Martys 1993:160 (Greylag Goose); Hunt et al. 1984 (Western Gull); Rogers and McCulloch 1981:90 (Galah).

This is especially true for “penis fencing” between male Bonobos, less so for mutual genital rubbing between females in this species. The latter usually involves one female “mounting” or embracing the other in a face-to-face position, hence it could be analogized with positions used in heterosexual interactions.

Even in some of these cases, however, a “pseudoheterosexual” framework has been imposed on the behavior. Mutual rump rubbing, in which two animals back up toward each other and rub their anal and genital regions together, has been interpreted as both animals adopting a “female” heterosexual invitation-to-mate posture in some species (e.g., Bonobos [Kitamura 1989:56—57]; Stumptail Macaques [Chevalier-Skolnikoff 1976:518]). This ignores the fact that both participants often actively rub their rumps together and make pelvic thrusts rather than simply passively presenting their hindquarters, and the two animals may also simultaneously fondle and stimulate each other’s genitals with their hands—clearly making this a distinct sexual activity rather than simply a version of a heterosexual practice or posture.

Bottlenose Dolphin (Ostman 1991). For more on reverse heterosexual mounting, see chapter 5 and the species profiles in part 2.

See, for example, Huber and Martys (1993:160) for explicit refutation of the idea that one member of a Greylag gander pair adopts a “pseudofemale” role.

This is true, for example, in Mallard Ducks, Black-crowned Night Herons, Black-headed Gulls, Emus, and Jackdaws.

Red Deer (based on table 2, Hall 1983:278).

Byne, W. (1994) “The Biological Evidence Challenged,” p. 53, Scientific American 270(5):50—55.

Northern jacana (del Hoyo, J., A. Elliott, and J. Sargatal, eds. [1996] Handbook of the Birds of the World, vol. 3, Hoatzin to Auks, p. 282 [Barcelona: Lynx Edicións]); arctic tern and other species (Weldon, P. J., and G. M. Burghardt [1984] “Deception Divergence and Sexual Selection,” Zeitschrift für Tierpsychologie 65:89—102, especially table 1).

Mountain Zebra (Penzhorn 1984:119); Chaffinch (Marler 1956:69, 96—97, 119) (Marler misleadingly labels some cases of opposite-sex mimicry as “homosexual behavior” while noting explicitly that no same-sex mounting occurs in these contexts); Rufous-naped Tamarin (Moynihan 1970:48, 50); Black-crowned Night Heron (Noble and Wurm 1942:216); Kittiwake (Paludan 1955:16-17); Koala (Smith 1980:49). Two species in which opposite-sex mimicry does appear to be a component of at least some homosexual interactions are Buff-breasted Sandpipers and Ocher-bellied Flycatchers.

Northern Elephant Seal (Le Boeuf 1974:173); Black-headed Gull (van Rhijn 1985:87, 100); Red Deer (Darling 1937:170); Common Garter Snake (Mason and Crews 1985:59). Researchers have also found that transvestite paketi (a fish species) have huge testes that are about five times larger than that of nontransvestite males and are thus able to fertilize more eggs (Ayling, T. [1982] Sea Fishes of New Zealand, p. 255 [Auckland: Collins]; Jones, G. P. [1980] “Growth and Reproduction in the Protogynous Hermaphrodite Pseudolabrus celidotus [Pisces: Labridae] in New Zealand,” Copeia 1980:660-75).

Tasmanian Native Hen (Ridpath 1972:30); Rhesus Macaque (Akers and Conaway 1979:76). On a related point, male Laysan Albatrosses may be stimulated to mount birds of either sex when the latter happen to assume a posture that resembles a female’s invitation to mate (typically involving drooping and spread wings)—to the extent that if only a bird’s right wing is drooping, for example, males on the bird’s right side will attempt to mount while those on the left will not. However, this “triggering” effect can only be a partial explanation, since males do not generally try to mount females who are sitting on a nest, even though the posture and drooping wings of such birds greatly resemble the mating invitation. Researchers studying this species (e.g., Fisher 1971:45-46) have expressed puzzlement over the apparent failure of the triggering effect in this context, suggesting that perhaps the height of the incubating females (nests in this species are six to eight inches high) is an inhibiting factor. This is not consistent, however, with the fact that males sometimes mount even taller “stacks” of up to three other males that are simultaneously mounting one another. Similarly, scientists once observed a Red Deer stag mount another male whose posture, as it was beginning to undergo the effects of a tranquilizer, supposedly “resembled” a female’s (Lincoln et al. 1970:101; cf. Klingel [1990:578] for a similar observation concerning anesthetized Plains Zebra stallions). Consequently, they attributed the homosexual behavior to the “triggering” effect of the supposedly femalelike visual cues presented by the other animal. Aside from the fact that the resemblance between a female Red Deer ready to mate and a drugged male is questionable, same-sex mounting in this species occurs commonly in contexts that have nothing to do with opposite-sex “resemblance” (cf. Hall 1983, Guiness et al. 1971; the same holds for Zebras).

Bighorn Sheep (Berger 1985:334; Geist 1971:161—63, 185, 219). Another possible case of heterosexual interactions being modeled on homosexual ones occurs in Atlantic Spotted Dolphins: during heterosexual copulations some individuals have been observed apparently “mimicking” the sideways mounting position used during interspecies homosexual copulations with Bottlenose Dolphins (Herzing and Johnson 1997:96). Interestingly, the patterning of heterosexual relations after homosexual ones is also found in some human cultures. In medieval Baghdad and Andalusia, for example, the preeminence of (largely intergenerational) homosexual relations was such that heterosexual women often cross-dressed as male youths—sometimes even with painted mustaches—in order to compete with boys for the attentions of men (Murray and Roscoe, Islamic Homosexualities, pp. 99, 151). In contemporary North America, some men cross-dress as women when having sex with their wives/girlfriends because they enjoy imagining themselves as a lesbian couple, or they become transsexual/transgendered women and live with their female partners in a lesbian relationship (see, for example, Money, J. [1988] Gay, Straight, and In-Between: The Sexology of Erotic Orientation, pp. 105-6 [New York: Oxford University Press]; Bolin, A. [1994] “Transcending and Transgendering: Male-to-Female Transsexuals, Dichotomy and Diversity,” p. 484, in G. Herdt, ed., Third Sex, Third Gender: Beyond Sexual Dimorphism in Culture and History, pp. 447-85 [New York: Zone Books]; Rothblatt, M. [1995] The Apartheid of Sex: A Manifesto on the Freedom of Gender, pp. 159-60 [New York: Crown]).

This is to some extent an arbitrary classification, since these three “types” may overlap with each other or even co-occur to varying degrees within the same species or individual. Nevertheless, they represent broad patterns that are a useful point of departure for discussion.

In the words of the scientists studing this species, “Female sexual displays formed a continuum from male-behaving females to normal females” (Buechner and Schloeth 1965:219).

Gorilla (Yamagiwa 1987a:13 [table 7], 1987b:36-37 [table 4]); Hanuman Langur (Srivastava et al. 1991:492— 93 [table II]); Bonnet Macaque (Sugiyama 1971:260 [table 9]); Pig-tailed Macaque (Tokuda et al. 1968:291 [table 7]).

Western Gull (Hunt et al. 1984).

On the rarity of incubation feeding in male-female pairs, see Evans Ogden and Stutchbury 1994:8.

Some cases of apparently role-differentiated behavior are not so clearly gendered when examined in more detail. Kitagawa (1988a:65—66) suggests that females in homosexual pairs of Black-winged Stilts can be divided into “malelike” and “femalelike” partners. However, many of the courtship and pair-bonding behaviors that are used to make this distinction, such as “splashing water” or “irrelevant preening,” are described by other sources (e.g., Goriup 1982; Hamilton 1975) as being performed by both sexes in heterosexual pairs. Even if we accept Kitagawa’s classification of some behaviors as more typical of males or females, though, in at least one of the homosexual pairs described, it is difficult to see how this translates into gendered behavior. Both partners in this case performed putatively female activities such as “extending neck” and egg laying, putatively male behaviors such as “half-circling round,” and putatively nongendered activities such as “showing nest spot” and incubation.

This behavior is exhibited by females when initiating pair-directed courtships, and by males when pursuing promiscuous matings (cf. Coddington and Cockburn 1995).

Swallow-tailed Manakin (Foster 1987:555; Sick 1967:17, 1959:286).

On the role differentiation of these parental duties in heterosexual pairs, see Martin et al. 1985:258.

Black-headed Gull (based on figs. 3-6, van Rhijn 1985:92-94). These comparisons are drawn from studies of captive birds; however, the behavior of wild Gulls appears to be similar—in a homosexual pair observed in the wild by Kharitonov and Zubakin (1984:103), for example, at least one partner exhibited a combination of both “male” and “female” behaviors.

For more extensive discussion of the full complexity and diversity of lesbian butch-femme, see Nestle, J. (1981) “Butch-Fem Relationships: Sexual Courage in the 1950’s,” Heresies No. 12, 3(4):21-24; Nestle, J., ed. (1992) The Persistent Desire: A Femme-Butch Reader (Boston: Alyson); Burana, L., Roxxie, and L. Due, eds. (1994) Dagger: On Butch Women (Pittsburgh and San Francisco: Cleis Press); Newman, L. (1995) The Femme Mystique (Boston: Alyson); Pratt, M. B. (1995) S/HE (Ithaca: Firebrand Books); Harris, L., and E. Crocker, eds. (1997) Femme: Feminists, Lesbians, and Bad Girls (New York: Routledge).

Australian Shelduck (Riggert 1977:60-61); Ring-billed Gull (Conover and Hunt 1984a); Mute Swan (Kear 1972:85-86); Mountain Sheep (Geist 1971:162); Bottlenose Dolphin (Tavolga 1966:729—30); Killer Whale (Rose 1992:112); White-handed Gibbon (Edwards and Todd 1991:234); West Indian Manatee (Hartman 1979:107-8); Hanuman Langur (Srivastava et al. 1991:508—9); Asiatic Elephant (Ramachandran 1984); Lion (Chavan 1981); Sage Grouse (Scott 1942:488).

For explicit rejection of (and evidence against) the shortage hypothesis by various zoologists studying animal homosexuality, see Gorilla (Harcourt et al. 1981:276); Japanese Macaque (Fedigan and Gouzoules 1978:494; Vasey 1996:550, 1998:17); Rhesus Macaque (Akers and Conaway 1979:77); Flamingo (King 1994:107); Common Gull (Riddiford 1995:112); Jackdaw (Röell 1978:103); Galah (Rogers and McCulloch 1981:90; Rowley 1990:59-60).

Orang-utan (Rijksen 1978:259); Japanese Macaque (Vasey 1996 and personal communication; Corradino 1990:360; Wolfe 1984); Stumptail Macaque (Chevalier-Skolikoff 1976:520); Rhesus Macaque (Akers and Conaway 1979:76–77); Common Gull (Riddiford 1995:112); Black-headed Gull (van Rhijn 1985:91–93); King Penguin (Murphy 1936:340—41); Galah (Rogers and McCulloch 1981:90; Rowley 1990:59–60).

Bottlenose Dolphin (Ostman 1991:310); Squirrel Monkey (Mendoza and Mason 1991:476–77; Travis and Holmes 1974:55, 63); Bonobo (Kano 1992:149; Savage-Rumbaugh and Wilkerson 1979:338); Stumptail Macaque (Chevalier-Skolikoff 1976:524); Savanna (Yellow) Baboon (Maxim and Buettner-Janusch 1963:176); West Indian Manatee (Hartman 1979:101, 106); Pukeko (Jamieson and Craig 1987a:1251); Common Murre (Birkhead et al. 1985:614); Sociable Weaver (Collias and Collias 1980b:248); Bonnet Macaque (Sugiyama 1971:252, 259—60); Japanese Macaque (Vasey 1996:543 and personal communication). Homosexual mounting rates can also be independent of the presence of animals of the opposite sex: in an all-female group of Pig-tailed Macaques, for example, the rate of same-sex mounting was virtually identical both before and after introduction of a male into the group (Giacoma and Messeri 1992:183 [table I]). The finding of a positive correlation between homosexual and heterosexual rates is paralleled by some data on humans in sex-segregated environments. Researchers found that married men in prisons who receive conjugal visits with their wives are actually more likely to have sex with other male prisoners than men without conjugal visits (Wooden, W. S., and J. Parker [1982] Men Behind Bars: Sexual Exploitation in Prison, pp. 55–56 [New York: Plenum]).

For species with skewed sex ratios but no homosexuality, see Welty, J. C., and L. Baptista (1988) The Life of Birds, 4th ed., p. 154 (New York: W. B. Saunders); Newton, I. (1986) The Sparrowhawk, pp. 37, 151 (Calton, England: T. and A. D. Poyser); Taborsky, B., and M. Taborsky (1991) “Social Organization of North Island Brown Kiwi: Long-Term Pairs and Three Types of Male Spacing Behavior,” Ethology 89:47-62. For verification of balanced sex ratios in populations exhibiting homosexuality, see Bonobo (Thompson-Handler et al. 1984:349); Bonnet Macaque (Simonds 1965); West Indian Manatee (Hartman 1979:139); Snow Goose (Quinn et al. 1989:184); California Gull (Conover et al. 1979); Pukeko (Craig 1980:594).

For sex ratios of various Seals and Sea Lions, see Fay 1982:256 (Walrus); for lunulated and salvin’s antbirds, see Willis, E. O. (1968) “Studies of the Behavior of Lunulated and Salvin’s Antbirds,” Condor 70:128—48; for other antbird species with a “surplus” of unmated males but no homosexual pairs, see Willis, E. O. (1969) “On the Behavior of Five Species of Rhegmatorhina, Ant-Following Antbirds of the Amazon Basin,” Wilson Bulletin 81:363–95.

Crab-eating Macaque (Poirier and Smith 1974); Pukeko (Craig 1980:594); Rhesus Macaque (Lindburg 1971:14, 69); Tree Swallow (Stutchbury and Robertson 1985, 1987b); Galah (Rogers and McCulloch 1981:90); Scarlet Ibis (Elbin and Lyles 1994:90–91); Flamingo (King 1994:104–5); Nilgiri Langur (Hohmann 1989:449); Little Egret (M. Fujioka, personal communication); Little Blue Heron (Werschkul 1982:382).

Black Stilt (Reed 1993:772); Humboldt Penguin (Scholten 1992:6 and personal communication); Savanna (Yellow) Baboon (Rowell 1967a:16, 22—23 [tables 2, 3]); Mallard Duck (Lebret 1961:108 [table I]).

Pig-tailed Macaque (Oi 1990a:340); Bottlenose Dolphin (Wells 1991:222); Cheetah (Eaton and Craig 1973:252); Koala (Smith 1980:184); Canada Goose (Collias and Jahn 1959:484); Flamingo (C. E. King, personal communication); Lesser Flamingo (Alraun and Hewston 1997:175–76).

Japanese Macaque (Chapais and Mignault 1991:172; Wolfe 1984:155); Giraffe (Dagg and Foster 1976:28, 124, 144); Greylag Goose (Huber and Martys 1993:160). Likewise, in Northern Fur Seal populations with up to 40 or more females for every male, a number of behavioral and other factors insure that nearly every female is still able to mate heterosexually (Gentry 1998:167, 192–93). For Macaques, some researchers have suggested that females resort to homosexuality when deprived of “novel” male partners rather than of males per se (i.e., when they “run out” of new partners or become overly familiar with them) (Wolfe 1984:155, 1986:274 [Japanese Macaque]; Huynen 1997 [Rhesus Macaque]). As Vasey (1996:550) points out, however, this explanation is flawed because the females they turn to are no more “novel” than the males are (and probably even less so, owing to the high levels of female bonding and familiarity in these species). In addition, some females continue to choose other females as partners even in populations that have novel males.

Gorilla (Robbins 1996; Fossey 1983, 1984; Harcourt et al. 1981); Hanuman Langur (Weber and Vogel 1970) Crested Black Macaque (Reed et al. 1997; Dixson 1977); Squirrel Monkey (DuMond 1968; Travis and Holmes 1974; Akers and Conaway 1979; Denniston 1980; Mendoza and Mason 1991); Walrus (Miller and Boness 1983; Sjare and Stirling 1996); Lion (Schaller 1972; Chavan 1981); Mallard Duck (Bossema and Roemers 1985; Schutz 1965:457–59); Black-headed Gull (Kharitonov and Zubakin 1984); West Indian Manatee (Hartman 1971, 1979); Cheetah (Eaton and Craig 1973; Eaton 1974a). In some of these cases (e.g., Gorillas, Hanuman Langurs) homosexual activity among males is much more common in same-sex groups although it still occurs sporadically or “residually” in mixed groups; in other cases (e.g., Squirrel Monkeys, Crested Black Macaques) homosexual activity is equally if not more common in at least some mixed-sex groups.

Squirrel Monkey (Talmage-Riggs and Anschel 1973:68, 71); Long-eared Hedgehog (Poduschka 1981:81).

Silver Gull (Mills 1991:1523, 1526); Mallard Duck (Schutz 1965:442); Canada Goose (Collias and Jahn 1959:500); Jackdaw (Röell 1979:126, table 1); Lesser Scaup Duck (Bellrose 1976:344); Caribou (Bergerud 1974:432).

Flamingo (Wilkinson 1989:53-54; King 1994:105; C. E. King, personal communication); Laughing Gull (Hand 1981:138-39); Humboldt Penguin (Scholten 1992:5); Gentoo Penguin (Stevenson 1983:192); Pied Kingfisher (Moynihan 1990:19; Reyer 80:220); Peach-faced Lovebird (Fischdick et al 1984:314); Galah (Rogers and McCulloch 1981:90); Bicolored Antbird (Willis 1967:112).

Cattle Egret (Fujioka 1986b:421-22); emperor and other penguins (Williams, T. D. [1995] The Penguins: Spheniscidae, pp. 80, 160 [Oxford: Oxford University Press]); dipper (Wilson, J. D. [1996] “The Breeding Biology and Population History of the Dipper Cinclus cinclus on a Scottish River System,” Bird Study 43:108—18); Oystercatcher (Heg and van Treuren 1998); Australian noisy miner (Dow, D. D., and M. J. Whitmore [1990] “Noisy Miners: Variations on the Theme of Communality,” in P. B. Stacey and W. D. Koenig, eds., Cooperative Breeding in Birds: Long-Term Studies in Behavior, pp. 559--92 [Cambridge: Cambridge University Press]); spotted sandpiper (Oring, L. W., J. M. Reed, and S. J. Maxson [1994] “Copulation Patterns and Mate Guarding in the Sex-Role Reversed, Polyandrous Spotted Sandpiper, Actitis macularia,” Animal Behavior 47:1065-72).

Redshank (Nethersole-Thompson and Nethersole-Thompson 1986:228); mustached warbler (Fessl, B., S. Kleindorfer, and H. Hoi [1996] “Extra Male Parental Behavior: Evidence for an Alternative Mating Strategy in the Moustached Warbler Acrocephalus melanopogon,” Journal of Avian Biology 27:88—91); Ostrich (Bertram 1992:125-26, 178); Greater Rhea (Navarro et al. 1998:117-18); Tree Swallow (Leffelaar and Robertson 1985); tropical house wren (Freed, L. A. [1986] “Territory Takeover and Sexually Selected Infanticide in Tropical House Wrens,” Behavioral Ecology and Sociobiology 19:197-206); barn swallow (Crook, J. R., and W. M. Shields [1985] “Sexually Selected Infanticide by Adult Male Barn Swallows,” Animal Behavior 33:754-61); Black Stilt (Pierce 1996:85); Silver Gull (Mills 1989:388); Herring Gull (Burger and Gochfeld 1981:128); African Elephant (Buss and Smith 1966:385—86; Kühme 1963:117).

White-handed Gibbon (Edwards and Todd 1991:234; Reichard 1995 a,b; Mootnick and Baker 1994); Ostrich (Sauer 1972:737); Buff-breasted Sandpiper (Lanctot and Laredo 1994:8; Pruett-Jones 1988:1748).

American Bison (Komers et al. 1994:324; D. F. Lott, personal communication); Bonobo (Hashimoto 1997:12— 13).

Musk-ox (Smith 1976:37, 56, 75-77; Gray 1979; Reinhardt 1985); Asiatic Elephant (Poole et al. 1997:304, 306—7 [fig. 5]); New Zealand Sea Lion (Marlow 1975:186, 203); Wolf (Zimen 1981:140); Killer Whale (Rose 1992:73, 83—84, 112, 116).

Ruff (Hogan-Warburg 1966:178—79, 199-200; van Rhijn 1991:69); Pukeko (Jamieson et al. 1994:271; Jamieson and Craig 1987a); Ocher-bellied Flycatcher (Westcott 1993:450); Ruffed Grouse (Gullion 1981:377, 379—80); Oystercatcher (Heg and van Treueren 1998: 689—90); Brown-headed Cowbird (Rothstein et al. 1986:150, 154—55, 167; Darley 1978); Guianan Cock-of-the-Rock (Trail and Koutnik 1986:209).

Giraffe (Dagg and Foster 1976:123; Innis 1958:258-60); Japanese Macaque (Vasey 1996 and personal communication; Corradino 1990:360; Wolfe 1984); Hanuman Langur (Srivastava et al. 1991); Gray Seal (Backhouse 1960:310); Killer Whale (Jacobsen 1990:75-78); Zebras (Rasa and Lloyd 1994:186); Great Cormorant (Kortlandt 1949); Orange-fronted Parakeet (Hardy 1965:152-53); Wapiti (Lieb 1973:61; Graf 1955:73; Harper et al. 1967:37); Ducks (McKinney et al. 1983). Most of these cases are also examples of a “preference” for homosexual activity in the participating individuals.

White-fronted Amazon Parrot (Clarke 1982:71); Long-eared Hedgehog (Poduschka 1981:81); Steller’s Sea Eagle (Pringle 1987:104); Barn Owl (Jones 1981:54); Rhesus Macaque (Erwin and Maple 1976:12-13); Crab-eating Macaque (Hamilton 1914:307-8); Bottlenose Dolphin (McBride and Hebb 1948:121); Cheetah (Ruiz-Miranda et al. 1998:7, 12); Black-headed Gull (van Rhijn and Groothuis 1987:142-43; van Rhijn 1985:91-93); Mallard Duck (Schutz 1965:442, 449—50, 460).

Ring-billed Gull (Conover and Hunt 1984a); Greylag Goose (Huber and Martys 1993:157[fig.1]).

Willson, M. F., and E. R. Pianka (1963) “Sexual Selection, Sex Ratio, and Mating Systems,” American Naturalist 97:405-7; Verner, J. (1964) “Evolution of Polygamy in the Long-billed Marsh Wren,” Evolution 18:252— 61; Verner, J., and M. F. Willson (1966) “The Influence of Habitats on Mating Systems of North American Passerine Birds,” Ecology 47:143—47; Wittenberger, J. E (1976) “The Ecological Factors Selecting for Polygyny in Altricial Birds,” American Naturalist 109:779-99; Wittenberger, J. E (1979) “The Evolution of Vertebrate Mating Systems,” in P. Marler and J. Vandenbergh, eds., Handbook of Neurobiology: Social Behavior and Communication, pp. 271-349 (New York: Plenum Press); Goldizen et al 1998 (Tasmanian Native Hen). For examples of (heterosexual) mating systems actually determining the sex ratio rather than vice versa, see Hamilton, W. D. (1967) “Extraordinary Sex Ratios,” Science 156:477-88; Wilson, D. S., and R. K. Colwell (1981) “Evolution of Sex Ratio in Structured Demes,” Evolution 35:882-97.

In Roseate Terns, for example, homosexual pairs were initially taken as evidence of skewed sex ratios, even though the sex ratio in this species had not yet been reliably determined (owing to the difficulty, until recently, of accurately determining the sex of individuals) (Sabo et al. 1994:1023, 1026).

Western Gull (Hunt and Hunt 1977; Hunt et al. 1980; Wingfield et al. 1980; Fry and Toone 1981; Fry et al. 1987; Hayward and Fry 1993); Herring Gull (Fitch 1979; Shugart et al. 1987, 1988; Pierotti and Good 1994).

For explicit refutation of an association between female homosexual pairs and environmental toxins, see Hunt 1980 (Western Gull); Lagrenade and Mousseau 1983; and Conover 1984c (Ring-billed Gull).

Fry et al. 1987; Fry, D. M., and C. K. Toone (1981) “DDT-induced Feminization of Gull Embryos,” Science 213:922-24.

Fry et al. 1987:37, 39; Fry and Toone 1981:923. Behavioral changes that could potentially be relevant have only been observed in other bird species, and only as a result of direct injection with estrogen, a female hormone, and not as a result of exposure to toxins (which mimic some of the effects of estrogen).

Indeed, if toxin-induced “feminization” resulted in behavioral changes, one might even expect this to be manifested directly as male homosexuality (especially under a “pseudoheterosexual” interpretation, or one in which homosexuality is equated with intersexuality), yet this has not been reported for these populations either. Even if such homosexuality were to occur, however, it would not necessarily argue for reduced numbers of breeding males: homosexually paired males in several bird species (including Black-headed and Laughing Gulls) sometimes continue to copulate with females (i.e., they are functionally bisexual and their same-sex pair bonds are nonmonogamous).

Herring Gull and other species (Fitch and Shugart 1983:6).

Western Gull (Fry et al. 1987); Herring Gull (Burger and Gochfeld 1981; Nisbet and Drury 1984:88). In these populations scientists have suggested that perhaps a cofactor is involved: availability of nest sites (Fry et al. 1987:40). The hypothesis is that homosexual pairs will only form in sex-skewed populations if there are vacant nest sites, since female pairs presumably are less able to compete for territories in dense colonies. However, Hand (1980:471) argues that homosexual pairs can effectively obtain (and defend) territories even in dense colonies. In addition, Fetterolf et al. (1984) show that female pairs of Ring-billed Gulls in crowded colonies are simply relegated to less optimal nest sites, rather than failing to form in the first place (or disbanding) because of competition or crowding. This “cofactor” is also of limited applicability to other bird species. In Orange-fronted Parakeets, for example, female pairs compete successfully against heterosexual pairs for possession of nest sites (Hardy 1963:187), while in many species female pairs form regardless of whether they acquire nesting sites (i.e., homosexual pair-formation is independent of nesting).

Herring Gull (Shugart et al. 1987, 1988); Ring-billed Gull (Conover and Hunt 1984a,b).

Watson, A., and D. Jenkins (1968) “Experiments on Population Control by Territorial Behavior in Red Grouse,” Journal of Animal Ecology 37:595–614; Weatherhead, P. J. (1979) “Ecological Correlates of Monogamy in Tundra-Breeding Savannah Sparrows,” Auk 96:391-401; Smith, J. N. M., Y. Yom-Tov, and R. Moses (1982) “Polygyny, Male Parental Care, and Sex Ratio in Song Sparrows: An Experimental Study,” Auk 99:555–64; Hannon, S. J. (1984) “Factors Limiting Polygyny in the Willow Ptarmigan,” Animal Behavior 32:153–61; Greenlaw, J. S., and W. Post (1985) “Evolution of Monogamy in Seaside Sparrows, Ammodramus maritimus: Tests of Hypotheses,” Animal Behavior 33:373-83; Gauthier, G. (1986) “Experimentally-Induced Polygyny in Buffleheads: Evidence for a Mixed Reproductive Strategy?” Animal Behavior 34:300-302; Björk-lund, M., and B. Westman (1986) “Adaptive Advantages of Monogamy in the Great Tit (Parus major): An Experimental Test of the Polygyny Threshold Model,” Animal Behavior 34:1436–40; Stenmark, G., T. Slagsvold, and J. T. Lifjeld (1988) “Polygyny in the Pied Flycatcher, Ficedula hypoleuca: A Test of the Deception Hypothesis,” Animal Behavior 36:1646-57; Brown-headed Cowbird (Yokel and Rothstein 1991).

Western Gull (Hunt and Hunt 1977); Herring Gull (Shugart et al. 1988). Fertility rates for homosexual pairs in other Gull species (not associated with environmental toxins) vary considerably, from 0 percent fertile eggs in Kittiwake female pairs (Coulson and Thomas 1985), 33 percent for Silver Gulls (Mills 1991), and 8-94 percent for Ring-billed Gulls (Ryder and Somppi 1979; Kovacs and Ryder 1983). Incidentally, only some of the males that copulate with female Western Gulls in homosexual pairs are known to be already paired; the remainder may in fact be single males that females are bypassing for pair-bonding, while utilizing them to fertilize their eggs (see Pierotti 1981:538-39). Also, some Silver Gulls in homosexual pairs may be raped by males, i.e., their particiption in breeding may be “forced” rather than “consensual” (Mills 1989:397).

Herring Gull (Fitch and Shugart 1984:123); Ring-billed Gull (Conover 1984b:714–16; Fetterolf and Blokpoel 1984:1682); Western Gull (Pierotti 1980:292); Roseate Tern (Spendelow and Zingo 1997:553). In Roseate Terns, females with proven single-parenting abilities nevertheless sometimes still form homosexual pairs, indicating that their same-sex partnership is not due solely to the “necessity” of finding a coparent (e.g., one female formed a homosexual pair even though she had successfully raised a chick on her own when her male partner died the previous year).

For an extensive list of species in which supernormal clutches have been found—only a fraction of which involve verified female pairs—see Conover 1984c (Ring-billed Gull). For other sources of supernormal clutches (and the occurrence of female pairs with regular-sized clutches), see Western Gull and other species (Conover 1984); Ring-billed Gull and other species (Conover and Aylor 1985; Conover and Hunt 1984; Ryder and Somppi 1979); Common Gull (Trubridge 1980); Terns (Penland 1984; Shealer and Zurovchak 1995; Gochfeld and Burger 1996:631); loons (McNicholl, M. K. [1993] “Supernumerary Clutches of Common Loons, Gavia immer, in Ontario,” Canadian Field-Naturalist 107:356–58); sandpipers and related species (Mundahl, J. T., O. L. Johnson, and M. L. Johnson [1981] “Observations at a Twenty-Egg Killdeer Nest,” Condor 83:180-82; Sordahl, T. A. [1997] “Breeding Biology of the American Avocet and Black-necked Stilt in Northern Utah,” pp. 350, 352, Southwestern Naturalist 41:348-54); Laysan Albatross (Fisher 1968). On the nonoccurrence of female pairs in certain species with supernormal clutches, see Narita, A. (1994) “Occurrence of Super Normal Clutches in the Black-tailed Gull Larus crassirostris,” Journal of the Yamashina Institute of Ornithology 26:132–34; Chardine, J. W., and R. D. Morris (1996) “Brown Noddy (Anous stolidus),” in A. Poole and F. Gill, eds., The Birds of North America: Life Histories for the 21st Century no. 220, pp. 10, 18 (Philadelphia: Academy of Natural Sciences; Washington, D.C.: American Ornithologists’ Union).

And sometimes the correlation between the two end points is itself suspect. For example, it has been claimed that supernormal clutches are more common in Great Lakes populations of Herring Gulls than they are in New England, a fact that is attributed to greater levels of DDT poisoning in the Great Lakes (Conover 1984c:254) and/or the absence of available nesting sites in New England (Fry et al. 1987:40; see note 65 above). However, Nisbet and Drury (1984:88) show that the “higher rate” of supernormal clutches in the Great Lakes can be traced to only one particular colony site; in three other Great Lakes areas censused, the prevalence of supernormal clutches was no greater than in New England. Moreover, even if such clutches are more common in the Great Lakes area, the fact that they still occur in New England indicates that their presence cannot be due entirely to pollutant-related (or nest-site availability) factors.

In Western Gulls, the correlation between toxins and supernormal clutches is claimed to be supported by chronological evidence: larger clutches were supposedly not common prior to the widespread use of pesticides in the 1950s–1970s in southern California, while female pairs are claimed to occur at a “much lower” rate (Hayward and Fry 1993:19) or to have all but disappeared (Pierotti and Annett 1995:11) now that pesticide use has stopped. However, no comprehensive survey of the affected areas has in fact been conducted to assess the actual incidence of female pairs today (even if such a study were to find consistently low levels, this would still be significant, since it would demonstrate a “residual” component of same-sex activity that is independent of toxin effects and of a “shortage” of the opposite sex, as is true for many other species). Nor have detailed longitudinal or geographic studies been conducted to track the putative correlations during this entire five-to-six-decade period. In fact, records of supernormal clutches in Ring-billed Gulls go back much earlier, to the early 1900s (and in other species back to the late 1800s), while in some Terns their frequency has actually decreased since the 1950s (Conover 1984c), so the chronological question is far from resolved. At least one researcher who has addressed the temporal issue rejects the DDT (or other pollutant) connection for the majority of cases: Conover (1984c:254) conducted an extensive survey of the occurrence of supernormal clutches in 34 species, including comparing pre- and post-1950 rates, and concluded that their frequency is not higher since the 1940s for most Gull and Tern species. Finally, no studies have yet determined the incidence of homosexual pairing/supernormal clutches in other regions of the world that have the highest levels of contamination from DDT and related pollutants, such as the Baltic Sea, the Waddensee, the Irish Sea, the Gulf of St. Lawrence, and the northern Gulf of Mexico (Nisbet, I. C. T. [1994] “Effects of Pollution on Marine Birds,” p. 13, in D. N. Nettleship, J. Burger, and M. Gochfeld, eds. Seabirds on Islands: Threats, Case Studies, and Action Plans, pp. 8–25. [Cambridge: BirdLife International]).

Hayward and Fry 1993:19; Luoma, J. R. (1995) “Havoc in the Hormones,” Audubon 97(4):60-67; Robson, B. (1997) “A Chemical Imbalance,” Nature Canada 26(1):29-33; see also Coulson 1983 (Caspian Tern). The equating of homosexuality with environmental and physiological “havoc” has also entered the more popular discourse, as in a recent public radio broadcast that referred to lesbian pairs in Gulls as evidence of hormonal imbalances caused by environmental contamination (“Gator Envy,” All Things Considered, National Public Radio, February 1, 1995). Some things not considered in this report were the broader context of same-sex pairing in other species and the intricacies of the specific cases. For more on the pathologizing of homosexuality, see the following section “Gross Abnormalities of Behavior.”

See, for example, Aiken (1981) on Water Boatman Bugs. Even this case is somewhat less than definitive, however, since more than half of all mating attempts in this species are by males on other males.

Guianan Cock-of-the-Rock (Trail 1985a:238, 240); Giraffe (Spinage 1968:130); Black-billed Magpie (Baeyens 1979:39–40); Mountain Sheep (Geist 1968:208). For examples of homosexual interactions that are explicitly labeled “mistakes” or “errors” (including, but not limited to, cases of sex misrecognition), see Asiatic Mouflon (Schaller and Mirza 1974:318-20); Common Murre (Birkhead et al. 1985:610-11); Oystercatcher (Makkink 1942:60); Laughing Gull (Hand 1981:139–40); Greater Rhea (Fernández and Reboreda 1995:323).

Redshank (Hale and Ashcroft 1982:471). Other species in which the occurrence of homosexuality is taken as the sole evidence of faulty sex recognition or “indiscriminate” mating or courtship include Cavies (Rood 1970:449), Little Brown Bats (Thomas et al. 1979:134), Shags (Snow 1963:93-94), Little Egrets (Fujioka 1988), Oystercatchers (Makkink 1942:67–68), Black-headed Gulls (van Rhijn 1985:87, 93), Superb Lyrebirds (Lill 1979a:496), and King Penguins (Murphy 1936:340). It should also be pointed out that the claim of “indiscriminate” sexual activity is often quite exaggerated: it is not uncommon for the mere existence of same-sex activity to be interpreted as evidence that the sex of the partner is immaterial, even when the animals show clear partner preferences, sometimes even favoring homosexual activity. For example, Trail and Koutnik (1986:210–11) claim that yearling Guianan Cock-of-the-Rock will mount any bird that sits still long enough; in fact, only one attempted heterosexual mount by a yearling was recorded during their study, compared to hundreds of homosexual mounts, and certain adult males were clearly mounted more often than others (ibid., 211–12, 215).

Yellow-eyed penguin (Richdale, L. E. [1951] Sexual Behavior in Penguins, p. 73 [Lawrence, Kans.: University of Kansas Press]); Silvery Grebe (Nuechterlein and Storer 1989:344); Red-faced Lovebird (Dilger 1960:667).

For species with adult-female/younger-male resemblances, see Rohwer, S., S. D. Fretwell, and D. M. Niles (1980) “Delayed Maturation in Passerine Plumages and the Deceptive Acquistion of Resources,” American Naturalist 115:400-437; for species with adult-female/adult-male resemblances, see Burley, N. (1981) “The Evolution of Sexual Indistinguishability,” in R. D. Alexander and D. W. Tinkle, eds., Natural Selection and Social Behavior, pp. 121-37 (New York: Chiron Press). A caveat about these cases is that the absence of homosexuality in a species is not necessarily a reliable form of evidence, since (as discussed in chapters 1-3) homosexual behavior is often hard to observe, easy to overlook, or deliberately ignored in the field.

Blackbuck (Dubost and Feer 1981:74-75); Guianan Cock-of-the-Rock (Trail and Koutnik 1986:199; Trail 1983); Swallow-tailed Manakin (Foster 1987:549; Sick 1967:17; 1959:286); Blue-backed Manakin (Snow 1963:172); Raggiana’s Bird of Paradise, Victoria’s Riflebird (Gilliard 1969:113, 223); Regent Bowerbird (Gilliard 1969:337); Superb Lyrebird (Smith 1982 and personal communication).

Mountain Goat (Chadwick 1983:14, 189–91); Bishop Birds (Craig and Manson 1981:13); Galah (Rogers and McCulloch 1981:81; Rowley 1990:4); Humboldt Penguin (Scholten 1987:200); King Penguin (Stonehouse 1960:11); Superb Lyrebird (Smith 1982 and personal communication); Ocher-bellied Flycatcher (Westcott and Smith 1994:678, 681; Snow and Snow 1979:286); Tree Swallow (Stutchbury and Robertson 1987c); Anna’s Hummingbird (Ortiz-Crespo 1972; Wells et al. 1996).

Andersson, S., J. Ornborg, and M. Andersson (1998) “Ultraviolet Sexual Dimorphism and Assortative Mating in Blue Tits,” Proceedings of the Royal Society of London, Series B 265:445–50; Hunt, S., A. T. D. Bennett, I. C. Cuthill, and R. Griffiths (1998) “Blue Tits Are Ultraviolet Tits,” Proceedings of the Royal Society of London, Series B 265:451-55; Witte, K., and M. J. Ryan (1997) “Ultraviolet Ornamentation and Mate Choice in Bluethroats,” in M. Taborsky and B. Taborsky, eds., Contributions to the XXV International Ethological Conference, p. 201, Advances in Ethology no. 32 (Berlin: Blackwell Wissenschafts-Verlag); Roper, T. J. (1997) “How Birds Use Sight and Smell,” Journal of Zoology, London 243:211-13; Bennett, A. T. D., I. C. Cuthill, J. C. Partridge, and E. J. Maier (1996) “Ultraviolet Vision and Mate Choice in Zebra Finches,” Nature 380:433-35; Waldvogel, J. A. (1990) “The Bird’s Eye View,” American Scientist 78:342-53; Cabbage White Butterfly (Obara 1970 and personal communication; Obara, Y [1995] “The Mating Behavior of the Cabbage White Butterfly,” paper presented at the 24^th International Ethological Conference, Honolulu, Hawaii); Superb Lyrebird (Reilly 1988:45).

Mountain Goat (Geist 1964:565); Musk-ox (Smith 1976:56); Cavies (Rood 1972:27, 54, 1970:443); Bighorn Sheep (Geist 1968:208); Common Murre (Birkhead et al. 1985:610-11); Flamingo (C. E. King, personal communication); Pronghorn (Kitchen 1974:44 [table 22]). In addition, some homosexual activity in Mountain Goats and Pronghorns also involves age-mates interacting with each other (adult males in Mountain Goats, younger males in Pronghorns). See also Wagner (1996) on Razorbills.

Swallow-tailed Manakin (Foster 1987:555); Laughing Gull (Noble and Wurm 1943:205); Black-headed Gull (van Rhijn and Groothuis 1985:163). Conversely, homosexuality has sometimes been attributed to behavioral identity between males and females. In Ruffed Grouse, for example, the nonaggressive or “submissive” posture of a male is similar to the behavior of a female during courtship, and that males court both sexes is attributed to their inability to distinguish “female-acting” males from actual females (Allen 1934:185; see also the discussion of “pseudoheterosexuality” earlier in this chapter). Aside from the fact that males and females are very different visually from each other in this species and therefore “there is no excuse for a male not recognizing a female” (as Allen [1934:180-81] observes), in the related red grouse there is a parallel identity between male “submissive” and female courtship behavior, yet males do not court other males in this species (Watson, A., and D. Jenkins [1964] “Notes on the Behavior of the Red Grouse,” British Birds 57:157).

Tree Swallow (Stutchbury and Robertson 1987a:719-20, 1987b:418). It is also unlikely that homosexual activity between adult males results from their mistaking one another for (adult) females. As Lombardo et al. (1994) point out, although the two sexes in this species look similar, the sex of at least one male involved in homosexual activity was nevertheless identifiable from his cloacal (genital) protuberance, lack of brood patch, and wing length. Most adult females are also visually distinct from males owing to the presence of a brown patch on the forehead (shorter wings also distinguish subadult females from subadult males) (Stutchbury and Robertson 1987c). In addition, same-sex copulations appear to be fairly uncommon in this species (Lombardo, personal communication)—certainly they are not nearly as frequent as one would expect if “mistakes” in sex recognition were prevalent.

Black-headed Gull (van Rhijn 1985:87, 100).

Hooded Warbler (Niven 1993:191) (cf. Lynch et al. [1985:718] for mean dimensions of other males). Niven (1993 and personal communication) suggests that it was also the female behavior patterns of this male that “triggered” the homosexual pairing, yet this bird’s behavior was actually a mixture of male and female patterns, involving, for example, incubation (female duties) as well as singing (male). Moreover, male Hooded Warblers are particularly attuned to differences in song pattern, using this information to recognize individual birds and then storing it in long-term memory for future use (Godard 1991). Because this male’s singing was highly distinctive, it is improbable that other males simply “disregarded” this aspect of his behavior or were “unaware” of his male status (especially given his physical characteristics). Furthermore, all “female” behaviors recorded in this individual occurred after the formation of the pair-bond—since pairs were not observed early in the breeding season, we do not in fact know whether this individual exhibited any (or only) “femalelike” patterns during courtship and pair-formation.

Hooded Warbler: differential attacking of males (Stutchbury 1994:65-67); mating success of malelike females (as evidenced by the fact that nests are fairly equally distributed between dark and light females) (Stutchbury et al. 1994:389[fig.6]; Stutchbury and Howlett 1995:95); promiscuous mating attempts on hooded females (Stutchbury et al. 1994:388).

Common Garter Snake (Mason 1993:261, 264; Mason et al. 1989:292; Mason and Crews 1985; Noble 1937:710–11); other species (Muma, K., and P. J. Weatherhead [1989] “Male Traits Expressed in Females: Direct or Indirect Sexual Selection?” Behavioral Ecology and Sociobiology 25:23-31; Potti, J. [1993] “A Male Trait Expressed in Female Pied Flycatchers Ficedula hypoleuca: The White Forehead Patch,” Animal Behavior 45:1245-47 [cf. also Sætre and Slagsvold 1992:295-96]; Tella, J.L., M. G. Forero, J.A. Donázar, and F. Hiraldo [1997] “Is the Expression of Male Traits in Female Lesser Kestrels Related to Sexual Selection?” Ethology 103:72-81; McDonald, D. B. [1993] “Delayed Plumage Maturation and Orderly Queues for Status: A Manakin Mannequin Experiment,” p. 38, Ethology 94:31-45). Experimental “disguising” of individuals to look like the opposite sex does not automatically induce “homosexual” behavior either. Female Chaffinches whose plumage has been painted to resemble male patterns, for example, are not courted by (nor do they form pair-bonds with) other females that “mistake” them for males (Marler 1955). Homosexual pairing does occur in this species, but between females that do not look like males. Likewise, yellowthroats (a bird species) are able to recognize the “true” sex of both males and females whose facial coloration has been manipulated to make them resemble the opposite sex. Similar results have been found for damselflies (Lewis, D. M. [1972] “Importance of Face-Mask in Sexual Recognition and Territorial Behavior in the Yellowthroat,” Jack-Pine Warbler 50:98-109; Gorb, S. N. [1997] “Directionality of Tandem Response by Males of a Damselfly, Coena-grion puella,” in M. Taborsky and B. Taborsky, eds., Contributions to the XXV International Ethological Conference, p. 138. Advances in Ethology no. 32 [Berlin: Blackwell Wissenschafts-Verlag]). In addition, in species such as lazuli buntings where juvenile males resemble adult females, experimental studies have demonstrated that adult males are in fact consistently able to distinguish the two sexes (Muehter, V. R., E. Greene, and L. Ratcliffe [1997] “Delayed Plumage Maturation in Lazuli Buntings: Tests of the Female Mimicry and Status Signalling Hypotheses,” Behavioral Ecology and Sociobiology 41:281–90).

Tree Swallow (Lombardo et al. 1994:555–56; Venier et al. 1993; Venier and Robertson 1991); Black-crowned Night Heron (Noble et al. 1938:29); Regent Bowcrbird (Marshall 1954:114-16); Greenshank (Nethersole-Thompson and Nethersole-Thompson 1979:114; Nethersole-Thompson 1951:104). In Tree Swallows, it is also unlikely that males cooperate during homosexual copulations in order to “appease” the birds mounting them and thereby avoid attack or injury (as suggested by Lonrbsrdo et al. 1994:556). Aggressive attacks in this species are characterized by a number of distinctive behavioral elements on the part of both the attacker (e.g., threat displays, grappling, pecking) and the bird being attacked (e.g., appeasement displays, submissive and distress calling) (cf. Robertson et al. 1992:6, 8)—and homosexual mountings exhibit none of these hallmarks.

Such cases contrast markedly with ones in which the pursued animal is clearly not a willing participant, such as Mountain Goats, Common Murres, or Anna’s Hummingbirds. In these instances, however, there are other arguments against a sex misrecognition analysis (as mentioned previously).

Swans (Kear 1972:85-86).

Wattled Starling (Sontag 1991:6); Common Chimpanzee (Kollar et al. 1968:444, 458); Gorilla (Coffin 1978:67); Stumptail Macaque (Bernstein 1980:32); Musk-ox (Reinhardt 1985:298-99); Koala (Smith 1980:186); Long-eared Hedgehog (Poduschka 1981:81; Reeve 1994:189); Vampire Bat (Greenhall 1965:442); Black-crowned Night Heron (Noble et al. 1938:14, 28-29). Factors such as stress or crowding have also been invoked for wild animals, such as Blue-bellied Rollers (Moynihan 1990).

Dolphins (Pilleri, G. [1983] “Cetaceans in Captivity,” Investigations on Cetacea 15:221-49); Barn Owl (Jones 1981); Rhesus Macaque (Strobel. I). [1979] “Behavior and Malnutrition in Primates,” in D.A. Levitsky, ed., Malnutrition, Environment, and Behavior: New Perspectives, pp. 193-218 [Ithaca: Cornell University Press]). Many reports of animal homosexuality and transgender have appeared in medical journals and other publications dealing with pathology. See, for example, the descriptions of same-sex activity among Common Chimpanzees in Kollar et al. 1968 (characterized as “perverse sexual acts”), which appeared in the Journal of Nervous and Mental Disease.

Cheetah (Eaton 1974a:116); Zebra Finch (Immelmann et al. 1982:422). The assessment for Cheetahs is particularly inappropriate in light of the fact that heterosexual activity is extremely difficult to observe in this species in the wild. As mentioned in chapter 1, during one ten-year study of Cheetahs, no heterosexual matings were seen over 5,000 hours of observation, and copulation has only been observed a total of five times in the wild during the entire scientific study of this species (Caro 1994:42). It is hardly surprising, therefore, that homosexual courtship and mating activity has so far only been seen in captivity. It should also be pointed out that male “coalitions” (bonded pairs or trios) have been observed in both wild and captive Cheetahs (wild [Caro and Collins 1986, 1987; Caro 1994]; captive [Eaton and Craig 1973:223; Ruiz-Miranda et al. 1998]). The assumption that sex segregation is completely “artificial” for male Cheetahs living in captivity is also false (see discussion below).

Fedigan 1982:143 (Japanese Macaque). See also Crews et al. (1983:228-30) and Crews and Young (1991:514) for similar statements challenging the supposed “abnormalcy” of same-sex copulation among Whiptail Lizards in captivity versus the wild.

In a few cases, specific homosexual activities, rather than the occurrence of homosexuality itself, have been observed in only wild or captive conditions. In Bonobos, for example, penis-fencing (a form of genital rubbing) has only been seen in the wild, while fellatio has only been observed in captivity (de Waal 1997:103–4). In addition, the duration of sexual acts can vary contextually: for example, de Waal (1987:326) found that episodes of genital rubbing between female Bonobos were considerably shorter in captivity (averaging around 9 seconds) than in the wild (averaging around 15 seconds).

Orang-utan (Nadler 1988: 107); Hamadryas Baboon (Kummer and Kurt 1965:74); Mule Deer (Halford et al. 1987:107); Musk-ox (Reinhardt 1985:298).

Bonobo, wild (Kano 1992:187 [table 24], 140; Kitamura 1989:53, 55-57, 61); Bonobo, captive (de Waal 1995:41 [table 3.1]); Black Swan (Braithwaite 1981:141-42). Five other species for which the relevant quantitative information is available are Pig-tailed, Crested Black, and Stumptail Macaques, Common Chimpanzees, and Vervets. Although the wild (or semi-wild) and captive figures in these cases are more difficult to compare (due to differences in group size and composition, observed behaviors, length of study periods, etc.), they also generally show fairly comparable rates. For Pig-tailed Macaques in the wild, 7-23 percent of mounting is same-sex, compared to about 25 percent in captivity (rates in the wild based on information in Oi 1990a:350—1 [including table [V], Oi 1996:345, and Bernstein 1967:226-27; captivity—Tokuda et al. 1968:287, 291 [table 7]). Among captive Crested Black Macaques, about 5 percent of mounting is between males (Dixson 1977:74, 77), compared to an estimated 8 percent in the wild (C. Reed, personal communication; figures for both of these species combine “copulatory” with “noncopulatory” mounts). However, another study (Bernstein 1970:94 [table IV]) yielded a much higher rate of same-sex mountings in captivity for these species—49 percent for Pigtails, 22 percent for Crested Blacks—demonstrating that there can be considerable differences between individual studies and/or populations (see also Bernstein [1967:228] for more on wild/captive comparisons in Pigtails). In Stumptail Macaques, 25 percent of sexual interactions (of all types) in captivity are homosexual (Chevalier-Skolnikoff 1974:100-101, 110), compared to 30-40 percent for mounting in a semi-wild troop (formerly captive animals that were transplanted and released) (Estrada et al. 1977:667 [fig.14]; Estrada and Estrada 1978:672 [table 4]). In Common Chimpanzees, same-sex mounting actually occurs more frequently in the wild: de Waal and van Hooff (1981:182 [table 2]) found that mounting between males in captivity constitutes only 1-2 percent of the behaviors involved in reassurance, enlistment of support, and other activities during conflicts, while Nishida and Hosaka (1996:120-21 [tables 9.5-9.6]) found that mounting accounts for one-third to one-half of such behaviors in wild Chimps. Likewise, Bernstein (1970:94 [table IV]) found that 9 percent of mounting activity in captive Vervets is same-sex, while Gartlan (1969:144, 146) and Struhsaker (1957:21, 27 [tables 8, 10]) both recorded 11 percent same-sex mounting in the wild. Rowell (1967b) also conducted a detailed quantitative comparison of behavioral frequency rates in the wild and captivity among Savanna (Olive) Baboons; unfortunately, mounting (and other sexual-behavior) rates between males in the wild could not be compared to rates in captivity because males were too aggressive to be kept together in captivity. On a related point, Rasa (1979b:321) found no substantial differences in Dwarf Mongoose same-sex (and opposite-sex) mounting rates when their behavior in crowded versus noncrowded captive conditions was compared (based on controlled observational regimes). Likewise, Heg and van Treuren (1998:689–90) did not find significantly higher rates of homosexual bonding (in the form of bisexual trios) when population densities increased among wild Oystercatchers.