red tail boa (female)

Question
I have a five year old red tailed boa who got very defensive when we placed a female, possibly pregnant mouse in her tank. She's struck at it, but hasn't attempted to actually kill it, they were more like warning strikes. One time she had a stare down with the mouse that lasted a good five minutes, about a minute into it Bailey(the boa) began to wave her head back and forth like she would to a threat. I was wondering if it had anything to do with the fact that it's the perfect time for her to breed. We're pretty sure the mouse is pregnant, she has wide set hips and a very plump pregnant looking belly. Could this have caused my snake's odd behavior toward what she would normally consider dinner?

Answer
Hi Christian, Very unlikely that the mouse's pregnant state had any effect on her reaction. Your other assumption is more likely correct. Your boa is right on schedule for breeding behaviour and the frequent refusal of food that goes with it. Early fall is exactly when it starts. I see exactly this behaviour with my colubrids in the early spring. The somewhat fearful reaction they display to what is normally prey can be surprising. Occasionally snakes in a shed or with retained eye-caps will act this way toward food as well.  Considering the timing, I'm pretty sure you are looking at breeding season fasting.