This list includes animals (birds, mammals, insects, fish, etc.) for which there is documented evidence of homosexual or transgender 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 states
"[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 widespread amongst social birds and mammals, particularly the sea mammals and the primates.[3]
"No species has been found in which homosexual behaviour has not been shown to exist, with the exception of species that never have sex at all, such as sea urchins and aphis. Moreover, a part of the animal kingdom is hermaphroditic, truly bisexual. For them, homosexuality is not an issue."
—Petter Bøckman[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 close to 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 because some assert it points to the naturalness of homosexuality in humans, while others counter that it has no implications and is nonsensical to use animal behavior to justify what is or is not immoral.[7][8] Animal preference and motivation is always inferred from behaviour. Thus homosexual behaviour has been given a number of terms over the years. The correct usage of the term homosexual is that an animal exhibits homosexual behaviour, however this article conforms to the usage by modern research[9][10][11][12] applying the term homosexuality to all sexual behaviour (copulation, genital stimulation, mating games and sexual display behaviour) between animals of the same sex.
Mammals
African Elephant[16]
Brown Bear[17]
Brown Rat[18]
Buffalo[19]
Caribou[20]
Cat (domestic)[21]
Cheetah[22]
Common Dolphin[23]
Common Marmoset[24]
Common Raccoon[25]
Dog (domestic)[26]
European Bison[27]
Human
Birds
Chicken (Domestic)[28]
Common Gull[29]
Emu[30]
King Penguin[31]
Fish
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.[32]Amazon molly[33]
Blackstripe topminnow[34]
Bluegill Sunfish[35]
Char[36]
Grayling[32]
European Bitterling[37]
Green swordtail[38]
Guiana leaffish[39]
Houting Whitefish[40]
Jewel Fish[41]
Least Darter (Microperca punctulata)[42]
Mouthbreeding Fish sp.[43]
Salmon spp.[44]
Southern platyfish[45]
Ten-spined stickleback[46]
Three-spined stickleback[46]
Other vertebrates
Anole sp.[47]
Appalachian Woodland Salamander[48]
Bearded Dragon[49]
Black-spotted Frog[50]
Broad-headed Skink[51]
Checkered Whiptail Lizard[49]
Chihuahuan Spotted Whiptail Lizard[49]
Common Ameiva[49]
Common Garter Snake[52]
Cuban Green Anole[47]
Desert Grassland Whiptail Lizard[49]
Desert Tortoise[53]
Fence Lizard[49]
Five-lined Skink[51]
Gopher (Pine) Snake[54]
Green Anole[47]
Inagua Curlytail Lizard[49]
Jamaican Giant Anole[47]
Laredo Striped Whiptail Lizard[49]
Largehead Anole[47]
Mountain Dusky Salamander[48]
Mourning Gecko[55]
Plateau Striped Whiptail Lizard[49]
Red Diamond Rattlesnake[56]
Red-tailed Skink[51]
Side-blotched Lizard[49]
Speckled Rattlesnake[57]
Tengger Desert Toad[58]
Water Moccasin[59]
Western rattlesnake (Crotalus viridis)[60]
Western Banded Gecko[55]
Whiptail Lizard spp.[49]
Wood Turtle[61]
[edit]
Insects and other invertebrates
Acanthocephalan Worms[62]
Alfalfa Weevil[63]
Australian Parasitic Wasp sp.[64]
Bean weevil sp.[65]
Bedbug and other Bug spp.[66][67]
Blister Beetle spp.[68]
Blood-flukes (Schistosoma)[69]
Blowfly[70]
Box Crab[71]
Broadwinged Damselfly sp.[72]
Cabbage (Small) White (Butterfly)[73]
Checkerspot Butterfly[73]
Clubtail Dragonfly spp.[74]
Cockroach spp.[75]
Common Skimmer Dragonfly spp.[74]
Creeping Water Bug sp.[76]
Cutworm[77]
Digger Bee[78]
Dragonfly spp.[74]
Eastern Giant Ichneumon (wasp)[64]
Eucalyptus Longhorned Borer[79]
Field Cricket sp.[80]
Fruit Fly spp.[81]
Glasswing Butterfly[73]
Grape Berry Moth[82]
Grape Borer[79]
Green Lacewing[83]
Harvest Spider sp.[84]
Hawaiian Orb-Weaver (spider)[84]
Hen Flea[85]
House Fly[86]
Ichneumon wasp sp.[64]
Incirrate Octopus spp.[71]
Japanese Scarab Beetle[87]
Jumping spider sp.[84]
Larch Bud Moth[82]
Large Milkweed Bug[88]
Large White (Pieris brassicae)[89]
Long-legged Fly spp.[90]
Mazarine Blue[91]
Mediterranean Fruit Fly[81]
Mexican White[92]
Midge sp.[90]
Migratory locust[93]
Mite sp.[90]
Monarch Butterfly[73]
Narrow-winged Damselfly spp.[72]
Parsnip Leaf Miner[90]
Pomace Fly[90]
Prea[94]
Queen Butterfly[73]
Red Ant sp.[90]
Red Flour Beetle[95]
Reindeer Warble Fly[90]
Rosechafer[90]
Rove Beetle spp.[96]
Scarab Beetle (Melolonthine)[97]
Screwworm Fly[90]
Silkworm Moth[82]
Sociable Weaver[90]
Southeastern Blueberry Bee[78]
Southern Green Stink Bug[98]
Southern Masked Chafer[90]
Southern One-Year Canegrub[90]
Spreadwinged Damselfly spp.[72]
Spruce Budworm Moth[82]
Stable Fly sp.[90]
Stag Beetle spp.[99]
Tsetse Fly[90]
Water Boatman Bug[100]
Water Strider spp.[101]