Nope. No other animals except humans can be “gay.” They often can be homosexual, however. Horses mount other male horses quite often and mules do also, and monkeys, chimps, dogs, ducks, geese, cats, etc all engage in homosexual behavior. It’s as natural as breathing is.

But the term “gay” denotes a whole lifestyle built around a homosexual preference, and only humans make their lives exclusively about their sexual preferences. And I am not saying that all humans do that either, some do but many don’t.

Some gay people make their whole lives about their homosexuality, and being “gay,” but not every homosexual person does. For some of us, it’s really just a sex preference, not a whole lifestyle, and that’s also fine - to each his own. I’m just pointing out that other animals don’t really have what can accurately be called “gay” lifestyles.