Why do animals exhibit same-sex sexual behavior?

Scientists have observed same-sex sexual behavior across over 1,500 animal species, taking forms such as courtship, pair bonding, and parenting. Proposed explanations for these behaviors vary widely by species and include mistaken identity, social bonding, and conflict reduction. Additionally, underlying genetic, hormonal, and neurological variations contribute to individual behavioral differences.

What we know

• Proposed causes for same-sex sexual behavior across species include mistaken identity, sexually antagonistic selection, balancing selection, reproductive practice, and social dominance or submission. [2]
• Genetic, hormonal, and neurological variations have been proposed as the basis for individual behavioral differences, and same-sex sexual behavior has been induced in laboratory animals using these means. [2]
• Studies on mammals suggest that same-sex behavior may help improve social stability by reducing conflict within groups. [3]
• Mistaken identity is noted as a specific proposed cause particularly for arthropods. [2]

Still open

• The precise motivations for and implications of non-reproductive and same-sex animal behaviors have yet to be fully understood.

Where to go next

• how we knowHow common is same-sex behavior across animal species?
• what caused itWhat role does social bonding play in animal interactions?
• the bigger pictureNon-reproductive sexual behavior in animals
• a case in pointWhich mammal species display homosexual behavior?
• compared withHow has observer bias affected research on animal sexuality?
• an unexpected connectionWhy might gut worms exhibit non-reproductive sexual interactions?Documented homosexual and non-reproductive behaviors span an unexpected phylogenetic breadth, stretching from primates all the way down to gut worms.

Sources

• [1]homosexual behavior in animals (Wikidata Q598540) · CC0 1.0
• [2]Homosexual behavior in animals · CC BY-SA 4.0
• [3]List of animals displaying homosexual behavior · CC BY-SA 4.0
• [4]Non-reproductive sexual behavior in animals · CC BY-SA 4.0
• [5]List of mammals displaying homosexual behavior · CC BY-SA 4.0