Something I’ve never given an ounce of thought to until I ran across this:
The sexual orientation of animals is one topic we know little about. Dogs, for instance, have been known to take great interest in our legs, but whether that means ol' Fido is gay, straight, or simply has a leg fetish, we can't say. However, studies on the overall topic do exist. A simple search on "are some animals gay?" resulted in a slew of articles.
One of the more interesting pieces comes from National Geographic. Written by James Owen, the article mentions several instances of animals engaging in homosexual behaviour. Two male penguins at New York's Central Park Zoo, Roy and Silo, have been "inseparable" for six years and have sex "while ignoring potential female mates." Other examples cited include male ostriches, flamingos, and female Japanese macaques.
An article from the San Francisco Chronicle mentions that "scientists have found homosexual behaviour throughout the animal world." Not surprisingly, these discoveries have led to debates over what conclusions can be drawn. Some believe this proves homosexuality is "natural" and not a choice. Others disagree.
No matter where you stand on the issue, one thing is apparent. As Marlene Zuk, a professor of biology at UC Riverside, puts it, sex in the animal kingdom isn't always just about reproduction.