List of animals displaying homosexual behavior

For these animals, there is documented evidence of homosexual behavior of one or more of the following kinds: sex, courtship, affection, pair bonding, or parenting, as noted in researcher and author Bruce Bagemihl's 1999 book Biological Exuberance: Animal Homosexuality and Natural Diversity.

Roy and Silo, two Central Park Zoo male chinstrap penguins similar to those pictured, became internationally known when they successfully hatched and cared for an egg they were given.[1]
Couple of male mallard ducks in a nature reserve in Germany

Bagemihl writes that the presence of same-sex sexual behavior was not "officially" observed on a large scale until the 1990s due to observer bias caused by social attitudes towards nonheterosexual people, making the homosexual theme taboo.[2][3] Bagemihl devotes three chapters, "Two Hundred Years at Looking at Homosexual Wildlife", "Explaining (Away) Animal Homosexuality" and "Not For Breeding Only" in his 1999 book Biological Exuberance to the "documentation of systematic prejudices" where he notes "the present ignorance of biology lies precisely in its single-minded attempt to find reproductive (or other) 'explanations' for homosexuality, transgender, and non-procreative and alternative heterosexualities."[4]

Petter Bøckman, academic adviser for the Against Nature? exhibit, stated "[M]any researchers have described homosexuality as something altogether different from sex. They must realize that animals can have sex with who they will, when they will and without consideration to a researcher's ethical principles." Homosexual behavior is found amongst social birds and mammals, particularly the sea mammals and the primates.[3] In 1986, it was even discovered amongst insects when butterfly scientist W.J. Tennent observed four male Mazarine blues competing for the attention of another male in Morocco.[5]

Sexual behavior takes many different forms, even within the same species and the motivations for and implications of their behaviors have yet to be fully understood. Bagemihl's research shows that homosexual behavior, not necessarily sex, has been documented in about five hundred species as of 1999, ranging from primates to gut worms.[2][6] Homosexuality in animals is seen as controversial by social conservatives because it asserts the naturalness of homosexuality in humans, while others counter that it has no implications and is nonsensical to equate natural animal behaviors to morality.[7][8] Sexual preference and motivation is always inferred from behavior. Thus homosexual behavior has been given a number of terms over the years. The correct usage of the term homosexual is that an animal exhibits homosexual behavior, however this article conforms to the usage by modern research,[9][10][11][12] applying the term homosexuality to all sexual behavior (copulation, genital stimulation, mating games and sexual display behavior) between animals of the same sex.

In October 2023, biologists reported studies of mammals (over 1,500 different species) that found same-sex behavior (not necessarily related to human orientation) may help improve social stability by reducing conflict within the groups studied.[13][14]

Mammals

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Selected mammals from the full list

Birds

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Homosexual behaviour is demonstrated by 120 known species of birds.[40] While an uptick in research on bird homosexuality – and animal homosexuality in general – has been coming out in recent years, it's common for some authors to labour in articulating the view any root cause or function of bird homosexuality is poorly understood.[41]

Hypotheses contrived in an attempt to explain the behaviour – homosexuality in birds – typically diverge from one another, further exacerbating an apparent perception in the concerned scientific communities knowledge's quest to realise bird homosexuality remains elusive as an objective. Some authors posit the behaviours are a result of any bird demonstrably homosexual being less inclined to rear young,[40] while other authors posit the timing of emergence from the egg is a factor.[42]

In 1977, The New York Times also reported on a colony of lesbian seagulls "off [the] coast of California."[43]

Selected birds from the full list

Fish

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Arctic grayling (Thymallus arcticus) leaping for a fly fisherman's bait. Research going back to the 1950s has shown both male and female graylings exhibit homosexual behavior.[53]

Reptiles

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Three species of Aspidoscelis

The all-female Whiptail lizard species Aspidoscelis neomexicanus (center), which reproduces via parthenogenesis, is shown flanked by two sexual species having males, A. inornatus (left) and A. tigris (right). Research has shown that simulated mating behavior increases fertility for Aspidoscelis neomexicanus. One female lies on top of another, playing the role of the male, the lizard that was on bottom has larger eggs, in most cases. The lizards switch off this role each mating season.[60]

Amphibians

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  • Appalachian woodland salamander[69]
  • Black-spotted frog[70]
  • Mountain dusky salamander[69]
  • Tengger desert toad[62]

Insects

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The head of a darner dragonfly (Basiaeschna janata)

Male homosexuality has been inferred in several species of dragonflies. A survey of damsel and dragonflies reveals characteristic cloacal pincher mating damage in 20–80 percent of the males, indicating a fairly high occurrence of sexual coupling between males.[71][72]

 
Male flour beetles engage in same-sex coupling to practice mating and to rid themselves of "old, less effective" sperm.

Other invertebrates

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See also

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Bibliography

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References

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  1. ^ Smith (February 7, 2004)
  2. ^ a b Bagemihl (1999)
  3. ^ a b c News-medical.net (2006)
  4. ^ Bagemihl (1999) page 213
  5. ^ Yeoman, Barry (2023-07-04). "Same-Sex Behavior Among Animals Isn't New. Science Is Finally Catching Up". National Wildlife Federation. Retrieved 2024-09-13.
  6. ^ Harrold (1999)
  7. ^ Solimeo (2004)
  8. ^ Solimeo (2004b)
  9. ^ Bagemihl (1999) pages 122-166
  10. ^ Roughgarden (2004) pp.13-183
  11. ^ Vasey (1995) pages 173-204
  12. ^ Sommer & Vasey (2006)
  13. ^ Zimmer, Carl (3 October 2023). "Same-Sex Behavior Evolved in Many Mammals to Reduce Conflict, Study Suggests - But the researchers cautioned that the work could not shed much light on sexual orientation in humans. + comment". The New York Times. Archived from the original on 4 October 2023. Retrieved 4 October 2023.
  14. ^ Gómez, José M.; et al. (3 October 2023). "The evolution of same-sex sexual behaviour in mammals". Nature. 14 (5719): 5719. Bibcode:2023NatCo..14.5719G. doi:10.1038/s41467-023-41290-x. PMC 10547684. PMID 37788987.
  15. ^ a b Bagemihl (1999) page 405
  16. ^ Hohmann, G.; Fruth, B. (July 2000). "Use and function of genital contacts among female bonobos". Animal Behaviour. 60 (1): 107–120. doi:10.1006/anbe.2000.1451. ISSN 0003-3472. PMID 10924210. S2CID 39702173. Archived from the original on 2023-02-06. Retrieved 2021-02-19.
  17. ^ Bagemihl (1999) page 441
  18. ^ a b Bagemihl (1999) page 469
  19. ^ Bagemihl (1999) pages 388,389
  20. ^ Bagemihl 1999) pages 81, 88
  21. ^ Bagemihl (1999) pages 81, 82, 89
  22. ^ de Waal (2001)
  23. ^ Liggett (1997–2006)
  24. ^ Imaginova (2007j)
  25. ^ Bagemihl (1999) pages 276–279
  26. ^ a b Bagemihl (1999) page 339
  27. ^ Bagemihl (1999) page 334
  28. ^ Bagemihl (1999) pages 310, 314
  29. ^ name="Biol. Exuberance: Dolphin
  30. ^ Bagemihl (1999) page 427
  31. ^ Bagemihl (1999) pages 218, 231, 317
  32. ^ Bagemihl (1999) page 391
  33. ^ Imaginova (2007d)
  34. ^ Bagemihl (1999) pages 81, 165, 205, 226, 231
  35. ^ a b Bagemihl (1999) page 432
  36. ^ Sell RL, Wells JA, Wypij D (June 1995). "The prevalence of homosexual behavior and attraction in the United States, the United Kingdom and France: results of national population-based samples". Archives of Sexual Behavior. 24 (3): 235–48. doi:10.1007/BF01541598. PMID 7611844. S2CID 12929812.
  37. ^ Wellings, K., Field, J., Johnson, A., & Wadsworth, J. (1994). Sexual behavior in Britain: The national survey of sexual attitudes and lifestyles. London, UK: Penguin Books.[page needed]
  38. ^ Stephanie H. Stack; Lyle Krannichfeld; Brandi Romano (2024). "An observation of sexual behavior between two male humpback whales". Marine Mammal Science. 40 (3). Bibcode:2024MMamS..40E3119S. doi:10.1111/mms.13119. hdl:10072/430033.
  39. ^ Bagemihl (1999) page 455-457
  40. ^ a b MacFarlane, Geoff R.; Blomberg, Simon P.; Vasey, Paul L. (2010-09-01). "Homosexual behaviour in birds: frequency of expression is related to parental care disparity between the sexes". Animal Behaviour. 80 (3): 375–390. doi:10.1016/j.anbehav.2010.05.009. ISSN 0003-3472. S2CID 53148085.
  41. ^ Regaiolli, Barbara (July 2018). "Investigating parental care behaviour in same-sex pairing of zoo greater flamingo (Phoenicopterus roseus)". The Open Access Journal for Life and Environment. 6: e5227. doi:10.7717/peerj.5227. PMC 6054785. PMID 30042888.
  42. ^ MacFarlane, Geoff R.; Blomberg, Simon P.; Kaplan, Gisela; Rogers, Lesley J. (2007). "Same-sex sexual behavior in birds: expression is related to social mating system and state of development at hatching". Behavioral Ecology. 18: 21–33. doi:10.1093/beheco/arl065. Retrieved 2023-12-04.
  43. ^ "Extensive Homosexuality Is Found Among Seagulls Off Coast of California". The New York Times. November 23, 1977. Retrieved 4 December 2023.
  44. ^ a b Bagemihl (1999) pages 632-5
  45. ^ Bagemihl (1999) pages 83
  46. ^ Bagemihl (1999) pages 544-8
  47. ^ a b Bagemihl (1999) page 621-6
  48. ^ Bagemihl (1999) pages 602-5
  49. ^ 365 Gay.com (2005)
  50. ^ Bagemihl (1999) pages 491-5
  51. ^ Bagemihl (1999) pages 606-10
  52. ^ Bagemihl (1999) page 639
  53. ^ a b c d Bagemihl (1999), page 665
  54. ^ Bagemihl (1999), page 37
  55. ^ a b c d Bagemihl (1999), pages 658, 664
  56. ^ a b c d e f g h i j k l m n Bagemihl (1999), page 658
  57. ^ Bagemihl (1999), page 664
  58. ^ Bagemihl (1999), pages 658, 665
  59. ^ Bagemihl (1999), pages 232, 233, 244
  60. ^ LeVay, (19 September 2007)
  61. ^ Vilet (2000), page 401 (page 19 in PDF)
  62. ^ a b c d e f g Bagemihl (1999), page 657
  63. ^ a b c d e f g h i j k Bagemihl (1999), page 657, 658
  64. ^ a b Budzinski, R.-M. (1997) Homosexuelles Verhalten bei Geckos der Gattung Phelsuma. Sauria 19 (3): 33-34
  65. ^ Bagemihl (1999), pages 232, 664
  66. ^ a b Bagemihl (1999), pages 663–664
  67. ^ "Turns out this 186-year-old tortoise has a gay lover". 19 October 2017. Archived from the original on 2018-01-24. Retrieved 2018-01-23.
  68. ^ Antelo, R (2012). "Caiman crocodilus (spectacled caiman) homosexual behavior". Herpetological Review. 43 (2): 327–328.
  69. ^ a b Bagemihl (1999), pages 657, 658
  70. ^ Bagemihl (1999), pages 243, 664
  71. ^ Dunkle (1991)
  72. ^ Young, L.C., et al. (2008)
  73. ^ a b c d e Bagemihl (1999), page 666
  74. ^ Tatarnic1 et al., 22 March 2006
  75. ^ a b c d e f g h i j k Bagemihl (1999) page 660
  76. ^ a b Bagemihl (1999) page 667
  77. ^ a b c Bagemihl (1999) pages 704, 713
  78. ^ a b c d e Bagemihl (1999) pages 150, 232, 236, 246
  79. ^ a b c Bagemihl (1999) pages 33–34, 196, 217, 219, 232
  80. ^ Bagemihl (1999) page 668
  81. ^ a b Benz G (May 1, 1973). "Role of sex pheromone, and its insignificance for heterosexual and homosexual behaviour of larch bud moth". Experientia. 29 (5): 553–554. doi:10.1007/BF01926659. S2CID 39282068.
  82. ^ a b c Bagemihl (1999) page 666
  83. ^ Bagemihl (1999) page 595
  84. ^ a b Bagemihl (1999) pages 9, 649, 665
  85. ^ Bagemihl (1999) page 658
  86. ^ Out magazine Archived 2017-09-16 at the Wayback Machine, By The Numbers sourced to the Journal of Evolutionary Biology; February 2009. Accessed 2009-01-17.
  87. ^ Dukas, R (November 2010). "Causes and consequences of male–male courtship in fruit flies". Animal Behaviour. 80 (5): 913–919. doi:10.1016/j.anbehav.2010.08.017. S2CID 54253398.
  88. ^ Bagemihl (1999) page 3
  89. ^ Kureck, I. M.; Neumann, A.; Foitzik, S. (2011). "Wingless ant males adjust mate-guarding behaviour to the competitive situation in the nest". Animal Behaviour. 82 (2): 339–346. doi:10.1016/j.anbehav.2011.05.008. S2CID 53164955.
  90. ^ a b Bagemihl (1999) pages 666, 660
  91. ^ Bagemihl (1999) pages 661–2
  92. ^ Bagemihl (1999) page 661
  93. ^ Lecomte, C.; Thibout, E.; Pierre, D.; Auger, J. (1998-04-01). "Transfer, Perception, and Activity of Male Pheromone of Acrolepiopsis assectella with Special Reference to Conspecific Male Sexual Inhibition". Journal of Chemical Ecology. 24 (4): 655–671. Bibcode:1998JCEco..24..655L. doi:10.1023/a:1022390102631. ISSN 0098-0331. S2CID 10001697.
  94. ^ a b c d e f g h i j k l m Bagemihl (1999), pages 661–2
  95. ^ Bagemihl (1999), page 659
  96. ^ Baker T (January 15, 1983). "Variations in male oriental fruit moth courtship patterns due to male competition". Experientia. 39 (1): 112–114. doi:10.1007/BF01960660. S2CID 99995.
  97. ^ Hall D, Cork A, Lester R, Nesbitt B, Zagatti P (July 1, 1987). "Sex pheromones of rice moth, Corcyra cephalonica Stainton". Journal of Chemical Ecology. 13 (7): 1575–1589. Bibcode:1987JCEco..13.1575H. doi:10.1007/BF00980201. PMID 24302328. S2CID 11253920.
  98. ^ Bagemihl (1999), page 661
  99. ^ Palaniswamy P, Seabrook W, Ross R (July 15, 1979). "Precopulatory behavior of males and perception of a potential male pheromone in spruce budworm". Annals of the Entomological Society of America. 72 (4): 544–551. doi:10.1093/AESA/72.4.544. S2CID 84678927.
  100. ^ Sanders C (September 1, 1975). "Factors affecting adult emergence and mating behavior of the eastern spruce budworm, Choristoneura fumiferana (Lepidoptera: Totricidae)". Canadian Entomologist. 107 (9): 967–77. doi:10.4039/ENT107967-9. S2CID 86477332.
  101. ^ Chaudhuri A, Sinha A (July 15, 1997). "A male-male pairing in the tropical tasar silkmoth, Antheraea mylitta (Saturniidae)". News of the Lepidopterists' Society. 39 (3): 39.
  102. ^ Schmieder-Wenzel C, Schruft G (January 12, 1990). "Courtship behaviour of the European Grape Berry Moth, Eupoecilia ambiguella Hb. (Lep., Tortricidae) in regard to pheromonal and tactile stimuli". Journal of Applied Entomology. 109 (1–5): 341–346. doi:10.1111/j.1439-0418.1990.tb00062.x. S2CID 86384073.
  103. ^ Zimmer (2000)
  104. ^ a b Bagemihl (1999) page 657
  105. ^ a b c Bagemihl (1999) pages 236, 704, 713
  106. ^ Bagemihl (1999), pages 668, 667
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INTERN 3
Note 3