My hand raised field mouse is starting to bite me

Question

I found Littles in a parking lot when he was a newborn. He still had his umbilical cord attached. Mother was nowhere to be found. With the help of Google, I was able to house and feed him. He is now 1 yr and 5 months old. He knows my voice, my smell, my touch. He loves me and my family loves him. Out of nowhere, about a week ago, he started biting me. Hard too. Drawing blood. I haven't done anything to him to warrant any biting. I'm basically his mother. He used to always let me pet him and would even turn his head to the side so I can scratch his jowls. So sweet. He would also like to run around in my robe that I wore. He would climb in one sleeve, go around the back (it was tied around my waist, so he couldn't call thru) and come out the other sleeve. He was very comfortable doing this. Now though, with his biting, I wouldn't dare put him near my body for biting reasons. I'm scared now to put my hand in the cage to do anything. Is it me? Is it something I'm doing? Or is it Littles? Is he going thru something that I'm not aware of? Is it testosterone? I would hate to have to get rid of him because he won't stop biting. I do not want my kids handling him. If he bites me (someone that hand raised him), he will surely bite my boys.

Anybody know what I should do or the reason why he is all of a sudden biting? I'm at a loss here. And very sad.

Answer 1

A lab mouse of 1,5 years of age is considered old, so we can definitely rule out puperty. Old age in lab mice means that this is typically the age where the effects of senescence set in.

So he might have joint pain or some inflammation or something else that makes him feel unwell. You might unknowingly have caused him pain by handling him, which prompted his biting. In that case a vet should have a look at him.

Another possibility is his instincts. Field mice are no domesticated animals. He has his instincts to survive firmly in place, even if you handraised him. Something you did, maybe even a subconscious twitch could have triggered his fighting instinct. We have similar questions here where cats suddenly attack their owner's faces without any obvious provocation. Our bodies are so big compared to those of our pets, we often don't even realize the small details and movements that trigger the instincts of our pets.

Answer 2

It is the best to have your friend examined by a doctor. However, in the meanwhile, have the following in mind:

1. He might need a partner for... a specific activity. He should be an adult by now, I guess.
2. His natural / wild instincts come to the surface.
3. The doctor should be able to tell if there is some affliction generating the behavioral change.