Biological Exuberance: Animal Homosexuality and Natural Diversity

function) for homosexual associations.

56

Rhesus Macaque (Carpenter 1942:149); Bottlenose Dolphin (Wells 1991:220); both of these cases are highly speculative. The Rhesus example is based on an isolated observation of a single consortship and is a questionable interpretation, while the Bottlenose case is considerably more complex than it initially appears (see discussion below).

57

Parker, G. A., and R. G. Pearson (1976) “A Possible Origin and Adaptive Significance of the Mounting Behavior Shown by Some Female Mammals in Oestrus,” Journal of Natural History 10:241—45; Thompson-Handler et al. 1984:355-57 (Bonobo); African Elephant (Buss 1990); Greenshank, Golden Plover (Nethersole-Thompson 1975:55).

58

Species in which homosexual activity among females has only been reported outside the breeding season (or when females are not in heat) include Wapiti, Barasingha, Waterbuck, and Gray- headed Flying Foxes.

59

Japanese Macaque (Gouzoules and Goy 1983:47); Hanuman Langur (Srivastava et al. 1991:508).

60

Hanuman Langur (Srivastava et al. 1991:508); Calfbird (Trail 1990:1849-50); Cheetah (Caro and Collins 1987:59, 62; Caro 1993:25, 1994:252, 304); Savanna Baboon (Noe 1992:295). For specific descriptions of animals of the opposite sex being “disinterested” or not attracted by homosexual activity, see Gorilla (Harcourt et al. 1981:276); White-handed Gibbon (Edwards and Todd 1991:232—33); Japanese Macaque (Wolfe 1984, Vasey 1995:190; Corradino 1990:360); Killer Whale (Jacobsen 1986:152); Gray Whale (Darling 1978:51-52); Northern Fur Seal (Bartholomew 1959:168); African Buffalo (Mloszewski 1983:186); Rufous Rat Kangaroo (Johnson 1980:356); Dwarf Cavy (Rood 1970:442); Laughing Gull (Noble and Wurm 1943:205); Sage Grouse (Scott 1942:495).

61

Bottlenose Dolphin (Florida—Wells 1991:219—20, Wells 1995; Ecuador—Felix 1997:14; Australia—Connor et al. 1992:419, 426; Bahamas—Herzing and Johnson 1997).

62

Squirrel Monkey (Travis and Holmes 1974:55); Stumptail Macaque (Chevalier-Skolnikoff 1976:524); Wolf (Zimen 1981:140); Savanna (Yellow) Baboon (Maxim and Buettner-Janusch 1963:176); Mountain Sheep (Geist 1971:162). For arguments against this being simple “displacement” or “redirected” (hetero)sexual activity, see chapter 4. On a related point, scientists have observed that male Oystercatchers in trios are unable to influence or “promote” homosexual activity among their female partners, yet males may suffer reproductive losses without the cooperation between females entailed by such same-sex activity (Heg and van Treuren 1998:690). Thus, males are essentially powerless to cultivate homosexual activity in females even when this activity may benefit them.

63

Dagg, “Homosexual Behavior and Female-Male Mounting in Mammals,” p. 179.

64

The one exception is R. Wrangham (quoted in Weinrich 1980:291), who suggests that male Gelada Baboons may essentially “perform” homosexual mounts in front of, and for the benefit of, females to demonstrate their mating “prowess.” This activity is not, however, claimed to be sexually stimulating for females in the same way that female homosexuality is claimed to be for males.

65

See discussion in chapter 4.

66

Kittiwake (Coulson and Thomas 1985); Western Gull (Hunt and Hunt 1977); Herring Gull (Shugart et al. 1988); Silver Gull (Mills 1991); Ring-billed Gull (Ryder and Somppi 1979; Kovacs and Ryder 1983). See also chapter 4 for further evidence against the claim that female pairs in Gulls form primarily as a breeding strategy.

67

Western Gull (Hunt et al. 1984); Black-winged Stilt (Kitagawa 1988); Lesser Scaup Duck (Afton 1993; Munro 1941); Acorn Woodpecker (W. D. Koenig, personal communication); Squirrel Monkey (Ploog 1967:159-60); Greylag Goose (Lorenz 1979, 1991); Oystercatcher (Heg and van Treuren 1998). Although female coparents in Acorn Woodpeckers are “platonic” in that they do not specifically engage in courtship or sexual behavior with one another, they still participate in the group mounting displays characteristic of this species (which usually include homosexual mounting and may actually involve mounting of their coparent).

68

Greater Rhea (Fernandez and Reboreda 1995:323, 1998:340-46); Lesser Scaup Duck (Afton 1993). The supposed “benefits” of having male nest helpers in Greater Rheas are also not readily apparent: researchers were able to demonstrate few, if any, statistically significant differences in breeding success between solitary males and those with helpers (these results are still preliminary, though, as the phenomenon has only recently been discovered; cf. Codenotti and Alvarez 1997).

69

Snow Goose (Martin et al. 1985:262-63); Black-billed Magpie (Dunn and Hannon 1989; Buitron 1988).

70

Superb Lyrebird (Lill 1979b, 1986). For a survey of mate and offspring desertion by one parent in a wide variety of bird species, see Szekely, T., J. N. Webb, A. I. Houston, and J. M. McNamara (1996) “An Evolutionary Approach to Offspring Desertion in Birds,” especially pp. 275-76, 310, in V. Nolan Jr., and E.D. Ketterson, eds., Current Ornithology, vol. 13, pp. 271-330 (New York: Plenum Press). For a summary of the effects of mate removal in more than 15 bird species, see Bart, J., and A. Tornes (1989) “Importance of Monogamous Male Birds in Determining Reproductive Success: Evidence for House Wrens and a Review of Male- Removal Studies,” Behavioral Ecology and Sociobiology 24:109—16.

71

Calfbird (Snow 1972:156, 1976:108); Japanese Macaque (Vasey 1998:13—14, 16); Oystercatcher (Heg and van Treuren 1998:688-89; Ens 1998:635); Jackdaw (Lorenz 1970:202-3); Lesser Scaup Duck (Munro 1941:130— 31); Canada Goose (Allen 1934:187-88).

72

See, for example, Srivastava et al. (1991:508-9) on female Hanuman Langurs, Huynen (1997:211) on female Rhesus Macaques, Gibson and Bradbury (1986:396) on female Sage Grouse, Jamieson and Craig (1987a:1252) on male Pukeko, and Wagner (1996:213) on male Razorbills.

73

See Gouzoules and Goy (1983:47) for an explicit refutation of this hypothesis in Japanese Macaques, and Vasey, “Homosexual Behavior in Primates,” for a more general refutation for primates. See also the discussion of mountee facilitation or initiation of homosexual interactions in chapters 3 and 4.

74

Pukeko (Jamieson and Craig 1987a:1252, 1987b:321-23; Jamieson et al. 1994:275-76); Ocher-bellied Flycatcher: only 4 out of 12 courtship interactions between males occurred when a female was present (Westcott and Smith 1994:680); Guianan Cock-of-the-Rock (Trail and Koutnik 1986).

75

Buff-breasted Sandpiper (Myers 1989:44-45; Pruett-Jones 1988:1745-47; Lanctot and Laredo 1994:9).

76

A. P. Moller, in Lombardo et al. 1994:556 (Tree Swallow).

77

As pointed out by Lombardo et al. (1994:556). In Tree Swallows, there are further arguments that reproductively oriented “sperm-swapping” is probably not involved. In one observation of homosexual mating in this species, the bird that other males were copulating with was already tending chicks, i.e., his mate could no longer be fertilized (the homosexual copulations occurred fairly late in the breeding season). Although some females may still have been fertile at that point because they had not yet laid eggs (M. P. Lombardo, personal communication), and reproductive copulations can occur fairly late in the season in this species (Robertson et al. 1992:11), it seems