My sister got 3 female rats about a week and a half ago from a pet store. They were only 4 weeks old (supposedly born on April 4th). Super adorable, her kids love them, yada yada. Yesterday we all went to her house for brunch, and my 6 year old nephew says to me "you need to look at my rat! She has a really full belly!" My first thought is that she has megacolon, a really awful and fatal condition... rats with high-white markings are at higher risk of developing it and she, of course, has high-white markings. And being 4 weeks old would be a logical age for her to start showing symptoms. Great. I get her out of the cage and start looking her over when I realize, this rat does not have megacolon. This rat is very pregnant. Her husband was ready to drop everything and bring her back to the pet store right then and there, but my sister, as much as she doesn't want rat babies.... really likes this particular rat and doesn't want to lose her. So they're keeping her. They called the pet store and the pet store said "oh, she was probably impregnated by her dad, because he was put in with them." WTF?? Why was he placed with them?! And they said they would take the babies, which is what sealed the deal on them deciding to keep her. On the bright side. If everything goes well, then that means I get rats again lol. My last one passed away a couple months ago and I wasn't planning on getting more for years.... but eh, if there are babies I will not pass them up haha.