Biological Exuberance: Animal Homosexuality and Natural Diversity

R. Wrangham, quoted in Bull, C. (1997) “Monkey Love,” The Advocate, June 10, 735:58. This is but one example of the often misleading statements about animal homosexuality that are perpetuated by both scientists and the popular press. See chapter 3 for further discussion.

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Females had an average of 5.2 different female partners and 4.1 male partners and ranged 4-9 female partners (out of a pool of 10) and 1—9 male partners (out of a pool of 10) (Idani 1991:91). Of course, all of these figures represent only a relatively short “snapshot” of Bonobo behavior (covering three months), but it is likely that longer-term or lifetime patterns exhibit a comparable spectrum of variation. Because female Bonobos are neither exclusively heterosexual nor exclusively homosexual, de Waal (1997:192) advocates use of the term pansexual to descibe their sexual orientation. This characterization is as appropriate as bisexual as long as it is understood that individuals exhibit a range of same-sex versus opposite-sex interactions (i.e., there are many gradations of “pansexuality” or “bisexuality” in this species).

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Of course, many other factors besides sexual “preference” are involved in the choice of mates, especially with regard to the availability and specific characteristics of partners. The fact that only some animals ever engage in homosexual or heterosexual activity, however, is an important indication that differences in sexual orientation probably also exist at an individual level. For further discussion of the role that partner availability may play in the occurrence of homosexual (and heterosexual) activity, see chapter 4.

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Silver Gull: data for 131 females tracked in the wild over their entire lives, from Mills 1991:1525 (table 1); Black-headed Gull: data for 27 males in a captive population studied for seven years, based on van Rhijn and Groothuis 1985:161 (table 3); Japanese Macaque: averages for 46-58 females over two consecutive years in a semiwild population, from Wolfe 1979:526; Galah: based on pair-bonding data over six years pooled from two captive populations comprising 27 birds, from Rogers and McCulloch 1981.

26

Vasey, “Homosexual Behavior in Primates,” p 197.

27

For explicit observations of the nonchalant responses of surrounding animals, including the heterosexual mates or parents of individuals involved in same-sex activity, see Common Chimpanzee (Kortlandt 1962:132); Gorilla (Harcourt et al. 1981:276); White-handed Gibbon (Edwards and Todd 1991:232—33); Japanese Macaque (Wolfe 1984; Vasey 1995:190); Killer Whale (Jacobsen 1986:152); Gray Whale (Darling 1978:55); Northern Fur Seal (Bartholomew 1959:168); African Buffalo (Mloszewski 1983:186); Lion (Chavan 1981:364); Rufous Rat Kangaroo (Johnson 1980:356); Dwarf Cavy (Rood 1970:442); Laughing Gull (Noble and Wurm 1943:205); Sage Grouse (Scott 1942:495). In the majority of cases where homosexual activities draw no response from surrounding animals, scientific observers simply make no comment about the behavior of the other animals. In one species, the Blue-bellied Roller, same-sex (and opposite-sex) “display” mounting is only performed when other birds are present to watch (but not intervene).

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African Buffalo (Mloszewski 1983:186); Musk-ox (Tener 1965:75).

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Other species in which harassment of heterosexual but not homosexual activity has been reported include Proboscis Monkeys (Yeager 1990a:224), Squirrel Monkeys (DuMond 1968:121-22; Baldwin and Baldwin 1981:304), Lechwe (Nefdt 1995), Wolves (Zimen 1976, 1981; Derix et al.1993), Red-necked Wallabies (Johnson 1989:275), Gray Squirrels (Koprowski 1992a:393; 1993:167—68), Kittiwakes (Chardine 1986), and King Penguins (Stonehouse 1960:32). In Hanuman Langurs, more than 83 percent of heterosexual copulations are harassed while harassment of homosexual ones only occurs occasionally (Sommer 1989a:208; Srivastava et al. 1991:497); for greater interruption of heterosexual mounts in Japanese Macaques, see Hanby 1974:840; in Moor Macaques, see Matsumura and Okamoto 1998:227-28. See also chapter 5 for further discussion of harassment of heterosexual matings.

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Bonobo (de Waal 1995:48, 1997:117, 120; Hashimoto 1997:12); Jackdaw (Röell 1978:29); Guianan Cock-of-the-Rock (Trail and Koutnik 1986:210—11). In a number of species (e.g., Rhesus and Crab-eating Macaques, Spotted Hyenas) a phenomeon known as scapegoating sometimes occurs, in which several individuals combine forces to attack another individual not directly involved in a dispute. Notably, individuals engaging in same-sex activity are not specifically targeted as scapegoats, and this behavior is not in fact generally related to sexual activity at all (Harcourt, A. H., and F. B. M. de Waal, eds., (1992) Coalitions and Alliances in Humans and Other Animals, pp. 87, 91, 129, 240 [Oxford: Oxford University Press]).

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