Just clipped this from a Google search
"A mouse is pregnant for 21 days, and after giving birth can become "with mouse" again within 12 hours!.....In a single litter a mouse can deliver anywhere from 4 to 12 offspring."
As soon as mice are sexually mature they will even mate with their own...
What I didnt know for the longest time was that mice can...... run vertically and sideways across an unpainted brick wall and do it almost as fast as they scurry across the floor,.... can climb and descend a vertical 1/2" copper pipe,.... leap almost 3 ft from the ground (to a bird seed bin)...