A month ago I was letting my rats play with my sisters male rat, and I looked away for 5 seconds then when I looked back they were latched together so I pulled them apart. There was some clear mucus like substance coming out of her private area. My rat isn't really showing much symptoms. She isn't even that big. She looks about the same size as her sister. I also heard that rats sometimes don't show symptoms or get big until a few days or even the day of when the babies will be born.