We will use a very basic definition of homosexuality. If you want to add your own definition, we can work with that as long as it is credible.
Here is the definition I'm using: a person who is sexually attracted to people of their own sex.
Now, if wanted, we can switch the word person to entity, or something that is more vague to encompass other lifeforms.
In light of the fact that science has no trouble using it to describe the activities of some animals I think it's quite reasonable to extend the definition to them as well.
"a person or animal who is sexually attracted to one of their own sex. Of course homosexuality has also been ascribed to animals regardless of the underlying reason, be it attraction or dominance. But
for purpose of this exchange I'll go along with your more limiting definition.
We don't see this happening in nature though, or at least can't show it for sure. We can't show that an animal is attracted to another animal of the same sex. We can show that they may have sex with another animal of the same sex, but the motivation behind sex in the animal kingdom is different, for the most part.
Dominance. Opportunity. A sexual drive that needs to be filled and a lack of females to fulfill that need.
Without asking, attraction is a rather difficult concept to ascribe to anything with certainty, be it human or other animal. Most often one would have to bluntly ask, "Are you attracted to X?" to be sure, which, of course is impossible with animals. So, we have to look for attraction signs in animals that mimic those in humans, and as it turns out there are such signs. The following examples are all taken from Wikipedia.
Bremerhaven Zoo in Germany attempted to encourage reproduction of endangered Humbolt penguins by importing females from Sweden and separating three male pairs, but this was unsuccessful. The zoo's director said that the relationships were "too strong" between the homosexual pairs.
penguin species where same-sex individuals mate for life and refuse to pair with females when given the chance.
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Approximately 8% of rams exhibit sexual preferences [that is, even when given a choice] for male partners (male-oriented rams) in contrast to most rams, which prefer female partners (female-oriented rams). We identified a cell group within the medial preoptic area/anterior hypothalamus of age-matched adult sheep that was significantly larger in adult rams than in ewes...
Scientists found that, "The oSDN in rams that preferred females was significantly larger and contained more neurons than in male-oriented rams and ewes.
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African and Asian males will engage in same-sex bonding and mounting. Such encounters are often associated with affectionate interactions, such as kissing, trunk intertwining, and placing trunks in each other's mouths.
I believe these all demonstrate an attraction to others of the same sex in animals.
