If there is a gay gene in nature, we should see gay dogs, gay cats, gay lions, gay deers. Been around animals a bit, never saw a male dog hump a male dog. Nor male ape hump a male ape. So what is the story with man???
As for chimpanzees, more closely related to humans than dogs are, from what little I've read on the subject, they're even worse than the dogs.
And then there are the famous lesbian sea gulls.
It's my observation that female dogs don't drive male dogs crazy any more than female humans drive male humans crazy. I know you won't disagree with this.
Just how similar human sexuality is to canine or ape I don't know, but I'm reluctant to dismiss it outright. Evidence to the contrary is too unconvincing--the wholesome, decent behavior of well-adjusted, happily married family men like you and me notwithstanding.