List of animals displaying homosexual behavior

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Further information: Homosexual behavior in animals
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.[1]
Couple of two male mallard ducks in a nature reserve in Germany

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.

Bagemihl writes that the presence of same-sex sexual behavior was not 'officially' observed on a large scale until the 1990s due to possible observer bias caused by social attitudes towards LGBT 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 realise 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]

Animal 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 observed in about 1500 species, ranging from primates to gut worms, and is well documented for 500 of them.[5][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 animal behavior to morality.[7][8] Animal 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.

Selected images[edit]

Three species of Cnemidophorus.

The all-female Whiptail lizard species Cnemidophorus neomexicanus (center), which reproduces via parthenogenesis, is shown flanked by two sexual species having males, C. inornatus (left) and C. tigris (right). Research has shown that simulated mating behavior increases fertility for Cnemidophorus neomexicanus. One female lies on top of another, playing the role of the male, the lizard that was on bottom has larger eggs. The lizards switch off this role each mating season.[13]

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.[14][15]

Mammals[edit]

Selected mammals from the full list:

Birds[edit]

Selected birds from the full list:

Fish[edit]

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.[47]


Reptiles[edit]

Amphibians[edit]

Insects[edit]

Male flour beetles are believed by scientists to engage in same-sex coupling to practice mating and to rid themselves of "old, less effective" sperm.[60]

Other invertebrates[edit]

See also[edit]

Bibliography[edit]


References[edit]

  1. ^ Smith (February 7, 2004)
  2. ^ Bagemihl (1999)
  3. ^ a b c News-medical.net (2006)
  4. ^ Bagemihl (1999) page 213
  5. ^ Bagemihl (1999)
  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. ^ LeVay, (19 September 2007)
  14. ^ Dunkle (1991)
  15. ^ Utzeri (1990)
  16. ^ a b Bagemihl (1999) page 405
  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. ^ Bagemihl (1999) page 427
  30. ^ Bagemihl (1999) pages 218, 231, 317
  31. ^ Bagemihl (1999) page 391
  32. ^ Imaginova (2007d)
  33. ^ Bagemihl (1999) pages 81, 165, 205, 226, 231
  34. ^ a b Bagemihl (1999) page 432
  35. ^ 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. 
  36. ^ 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]
  37. ^ Bagemihl (1999) page 455-457
  38. ^ Bagemihl (1999) page 448
  39. ^ Bagemihl (1999) pages 632-5
  40. ^ Bagemihl (1999) pages 83
  41. ^ Bagemihl (1999) pages 544-8
  42. ^ Bagemihl (1999) page 621-6
  43. ^ 365 Gay.com (2005)
  44. ^ Bagemihl (1999) pages 491-5
  45. ^ Bagemihl (1999) pages 606-10
  46. ^ Mating Call (1979)
  47. ^ a b c d Bagemihl (1999), page 665
  48. ^ Bagemihl (1999), page 37
  49. ^ a b c d Bagemihl (1999), pages 658, 664
  50. ^ a b c d e f g h i j k l m n Bagemihl (1999), page 658
  51. ^ Bagemihl (1999), page 664
  52. ^ Bagemihl (1999), pages 658, 665
  53. ^ Bagemihl (1999), pages 232, 233, 244
  54. ^ a b c d e f g Bagemihl (1999), page 657
  55. ^ a b c d e f g h i j k Bagemihl (1999), page 657, 658
  56. ^ Bagemihl (1999), pages 232, 664
  57. ^ a b Bagemihl (1999), pages 663–664
  58. ^ a b Bagemihl (1999), pages 657, 658
  59. ^ Bagemihl (1999), pages 243, 664
  60. ^ a b Out magazine, By The Numbers sourced to the Journal of Evolutionary Biology; February 2009. Accessed 2009-01-17.
  61. ^ a b c d e Bagemihl (1999), page 666
  62. ^ Tatarnic1 et al., 22 March 2006
  63. ^ a b c d e f g h i j k Bagemihl (1999) page 660
  64. ^ a b Bagemihl (1999) page 667
  65. ^ a b c Bagemihl (1999) pages 704, 713
  66. ^ a b c d e Bagemihl (1999) pages 150, 232, 236, 246
  67. ^ a b c Bagemihl (1999) pages 33–34, 196, 217, 219, 232
  68. ^ Bagemihl (1999) page 668
  69. ^ a b c Bagemihl (1999) page 666
  70. ^ Bagemihl (1999) page 595
  71. ^ a b Bagemihl (1999) pages 9, 649, 665
  72. ^ Bagemihl (1999) page 658
  73. ^ Bagemihl (1999) page 3
  74. ^ a b c d Bagemihl (1999) page 232
  75. ^ a b Bagemihl (1999) pages 666, 660
  76. ^ Bagemihl (1999) pages 661–2
  77. ^ Bagemihl (1999) page 661
  78. ^ a b c d e f g h i j k l m Bagemihl (1999), pages 661–2
  79. ^ Bagemihl (1999), page 659
  80. ^ Bagemihl (1999), page 661
  81. ^ Zimmer (2000)
  82. ^ a b Bagemihl (1999) page 657
  83. ^ a b c Bagemihl (1999) pages 236, 704, 713
  84. ^ Bagemihl (1999), pages 668, 667