I am not home to check that link, but any link related to scientific studies but the link doesn't have .edu or .gov extension at the end. Then it's not worth your time or mine. Anyone can say anything on the internet, only certified sources should be considered in a scientific debate.
There's literally a BBC article about how animals are not homosexual by nature, humans and home bred sheep are the only species that actually have homosexuality.
But I am not using it for an argument because it's not a .edu or .gov
Also that's about mice not humans.