My husband brought me home 3 rats, he doesn't know much about them so when he was told they were all female he didn't pay much attention. Turns out there were 2 males and 1 female. Within a day, one of the rats died and left me with the male and female. I wanted babies so I allowed a litter.

Now mama's had her litter and I want to separate the two at least until the male babies are old enough to introduce to the older male, until then he will be all alone and I'm not sure what to do.

Will he be okay without a companion in his cage for awhile? They are both young rats, should I allow them time to play together even though I'm pretty sure she will end up pregnant again? She's had 14 and I don't need anymore rats because it's laughably ridiculous!

1 Answer 1


Sounds like you have a problem already. I didn't have mixed sex rats, but a quick google check gives a quite surprising answer:

Females go into heat between about 10 and 24 hours after giving birth. Specifically, females go into heat on the first evening that is at least 10 hours after giving birth (Gilbert et al. 1985). This phenomenon of coming into heat shortly after giving birth is called postpartum estrus.


So I recommend to buy a second cage and separate them ASAP.

And then before they turn 8 weeks old you should also check their sex and separate the young ones too. I recommend taking them to the vet if you're not sure - it sometimes can be hard with young rats.

Generally, male laboratory rats will reach sexual maturity at approximately 10-12 weeks of age, although females may have their first estrus as early as 8-9 weeks of age.


  • I have them seperated at the moment.. I took him out of the cage as soon as I realized she went into labor. I also have multiple cages so space isn't an issue. I'm more concerned about my young male being alone for the next few weeks till other males are old enough to ween. Commented May 26, 2020 at 0:19
  • I would recommend neutering the male (father) rat. For young rats it doesn't take long to recover - after a week he should be like new :) Although I only have a herd of female rats so I'm not sure how neutering affects male ones - their behavior, for females it has a good influence on their health but they are more likely to gain weight.
    – Picard
    Commented May 26, 2020 at 6:35

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