If not, than why do animals engage in homosexual sex when they're not doing it for enjoyment and it's not for procreating? Yet, this list lacks detailed descriptions, and a more comprehensive summary of its prevalence in invertebrates, as well as ethology, causes, implications, and evolution of this behavior, remains lacking". The Amazon river dolphin or boto has been reported to form up in bands of 3—5 individuals engaging in sexual activity. They might split up when they find a pride where they can overpower the reigning male or they might live their whole lives as a bachelor couple. Zimmer, Carl ; Parasite Rex: Stellflug; Fred Stormshak More than 20 species of bat have been documented to engage in homosexual behavior.
In a footnote he gives the source and considers another study:
A giraffe same-sex relationship?
He may combine this with the 'twist,' in which the courting male sharply rotates his head and points his muzzle toward the other male, often while flicking his tongue and making grumbling sounds. European polecats Mustela putorius were found to engage homosexually with non-sibling animals. Retrieved on 18 November Animal preference and motivation is always inferred from behavior. X-rays of Gemina's neck showed that her vertebrae had fused together, but scientists, zoologists and veterinarians could find no explanation for the deformity. Thinhorn rams additionally lick the penis of the male they are courting.