Mouse nipples

Question
Hi!  I appreciate you taking my question.  I live in the country and consequently sometimes have mice in my basement.  I humanely live trap and release them, in a brushy, wooded area, far away from my house, with a small supply of food.  It's not ideal, but it's the best I can do for them.  I use the Smart Mouse trap and it works well.  

This morning, I caught a mouse who appeared to have visible nipples (two to four darker colored "dots" on her white underside).  I was afraid she might have babies, so I released her right outside my house (yes, I know she'll be right back in!).  My question is this:  do all female mice have visible nipples, or just those who are nursing or pregnant?  It would help me to know which ones I can relocate without worry.    

Thanks for any help you can give me!

Answer
Dear Amy,

Thank you so much for caring. You are right. If you can see her nipples, she is nursing.

Make sure you always let them go over a mile from your house because they have large territories and you may find yourself catching the same mice several times-- if they aren't too smart to be caught the second time.


squeaks n giggles,

Natasha