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.

Homosexual behavior is widespread amongst social birds and mammals, particularly the sea mammals and the primates.

Selected mammals from the full list:
* African Elephant
* Brown Bear
* Brown Rat
* Buffalo
* Caribou
* Cat (domestic)
* Cheetah
* Common Dolphin
* Common Marmose
* Common Raccoon
* Dog (domestic)
* European Bison
* Prea

Selected birds from the full list:
* Chicken (Domestic)
* Common Gull
* Emu
* King Penguin

Fish:
* Amazon molly
* Blackstripe topminnow
* Bluegill Sunfish
* Char
* Grayling
* European Bitterling
* Green swordtail
* Guiana leaffish
* Houting Whitefish
* Jewel Fish
* Least Darter (Microperca punctulata)
* Mouthbreeding Fish
* Salmon
* Southern platyfish
* Ten-spined stickleback
* Three-spined stickleback

Reptiles:
* Anole
* Bearded Dragon
* Broad-headed Skink
* Checkered Whiptail Lizard
* Chihuahuan Spotted Whiptail Lizard
* Common Ameiva
* Common Garter Snake
* Cuban Green Anole
* Desert Grassland Whiptail Lizard
* Desert Tortoise
* Fence Lizard
* Five-lined Skink
* Gopher (Pine) Snake
* Green Anole
* Inagua Curlytail Lizard
* Jamaican Giant Anole
* Laredo Striped Whiptail Lizard
* Largehead Anole
* Mourning Gecko
* Plateau Striped Whiptail Lizard
* Red Diamond Rattlesnake
* Red-tailed Skink
* Side-blotched Lizard
* Speckled Rattlesnake
* Water Moccasin
* Western rattlesnake (Crotalus viridis)
* Western Banded Gecko
* Whiptail Lizard spp.
* Wood Turtle

Amphibians:
* Appalachian Woodland Salamander
* Black-spotted Frog
* Mountain Dusky Salamander
* Tengger Desert Toad

Insects and other invertebrates:
* Acanthocephalan Worms
* Alfalfa Weevil
* Australian Parasitic Wasp
* Bean weevil
* Bedbug and other Bug
* Blister Beetle
* Blood-flukes (Schistosoma)
* Blowfly
* Box Crab
* Broadwinged Damselfly
* Cabbage (Small) White (Butterfly)
* Checkerspot Butterfly
* Clubtail Dragonfly
* Cockroach
* Common Skimmer Dragonfly
* Creeping Water Bug
* Cutworm
* Digger Bee
* Dragonfly
* Eastern Giant Ichneumon (wasp
* Eucalyptus Longhorned Borer
* Field Cricket
* Flour beetle
* Fruit Fly
* Glasswing Butterfly
* Grape Berry Moth
* Grape Borer
* Green Lacewing
* Harvest Spider
* Hawaiian Orb-Weaver (spider)
* Hen Flea
* House Fly
* Ichneumon wasp sp.
* Incirrate Octopus spp.
* Japanese Scarab Beetle
* Jumping spider
* Larch Bud Moth
* Large Milkweed Bug
* Large White (Pieris brassicae)
* Long-legged Fly
* Mazarine Blue
* Mediterranean Fruit Fly
* Mexican White
* Midge
* Migratory locust
* Mite
* Monarch Butterfly
* Narrow-winged Damselfly
* Parsnip Leaf Miner
* Pomace Fly
* Queen Butterfly
* Red Ant
* Red Flour Beetle
* Reindeer Warble Fly
* Rose Chafer
* Rove Beetle
* Scarab Beetle (Melolonthine)
* Screwworm Fly
* Silkworm Moth
* Sociable Weaver
* Southeastern Blueberry Bee
* Southern Green Stink Bug
* Southern Masked Chafer
* Southern One-Year Canegrub
* Spreadwinged Damselfly
* Spruce Budworm Moth
* Stable Fly
* Stag Beetle
* Tsetse Fly
* Water Boatman Bug
* Water Strider