I don't understand this. Shouldn't the behavior be constant?
Have you been able to coax good days out of her by changing the environment, food, your behavior, etc? Can you predict the bad days? Is there a pattern?
Spoken like a programmer. Adults aren't even consistent. Ever seen a woman going completely apeshit at a male for some reason (sometime justified, sometimes not)?
Biological organisms have significant variations. Sometimes you get an angel; sometimes you get a devil; sometimes both.
In the past, resources were sufficiently scarce that children (and adults) who weren't capable of fitting into society were killed or allowed to die.
Why would you use that example?
I have easily seen a dozen or more incidents of women doing this in public. I have only ever once seen a man do this.
I suspect the imbalance is because men prone to this behavior resort to violence privately. Strangers will step in to help a woman but not a man.