Grassy Field Of Anecdotal Evidence
This I saw personally, I speak from direct experience.
Our Transsexual Pets
I personally have witnessed examples of transsexuality in animals many times throughout my life. I have certainly seen my share of other people's dogs who "Just Don't know He's a 'He'", or the reverse, and this could be observed in how they attempted to urinate, or to cope with the sexual advances of another dog. There can be little doubt when a female dog raises a leg to urinate, covering it's legs in it's own fluids, that a 'male' patch of neurons is causing the behavior. By the same token, the physically male dog I observed squatting to urinate, and wetting it's entire underbelly must have been operating from an internal and inborn female behavior map. There are no gender stereotypes in dog society.
As a teenager, I owned two physically female mice, which inhabited a virtual city of 'Habitrail' tubes and chambers that covered the walls of my bedroom. One of the mice behaved in every way as a male, and was forever attempting to mount the other, causing endless stress for both.
But most dramatic was the pet of one of my spouses, a rat we named 'Kelly' after it's favorite treat, corn flakes. Though physically female, Kelly was male in all behaviors, and would regularly mount and attempt to mate with my hand. Kelly pumped away with it's little pelvis, yet was devoid of the male organs associated with this behavior. In one circumstance where -do to a misunderstanding- Kelly came into contact with a male rat, Kelly would have killed the other rat for it's attempt to mate had we not intervened...kelly wanted only to be on top.
Transsexuality is fairly common in rats, as they are easily stressed -being rather nervous creatures- and the hormone fluxes result in quite a few transgendered rodents. This is hardly a problem to their reproductive survival, considering the number of offspring they produce! I am also of the opinion that this may be of value to the species as I describe in the 'Why' section of the site.
Quite the matter of study, the ability to effectively 'create' transsexualized animals by inducing stress at critical times during pregnancy, is something easily observable outside the laboratory. Anyone who has spent any time around animals will have seen similar occurrences. My mother, who grew up on a ranch, also related stories of her experiences of such animals as sheep and goats having gender problems.