"Ok, ill give you the short version. Back way when, a long time ago sometime, i was on earth. I used to be a normal, average, non-interesting arctic fox. Then one day i got kid-napped by some scientists and they made me into something else. That something else being an anthropoorphic hermaphrodite, or herm, for short. Their original purpose for me was for me to..well..make more little me's if you get the idea. One day, conveniently after all their tests had been concluded, something bad happened there and i escaped. While i was there, they did something to me that allows me to...uh, how to i put this, change gender at will? Yeah, thats it. Every winter i'll go into heat for a few weeks or something and im stuck as female for that time. Make sense?"