Breeding rats

Female rats come into heat every 5 days. When they come in heat, it lasts overnight, so night-time is the best time to put the male in with her. It is also best to keep them together for around 10 days, to make sure that there have been 2 heat cycles.

The gestation period is 21 days. During the last few days of pregnancy, the female will suddenly look VERY big, and you may be able to see the babies moving around inside her. It is important not to disturb her in these last few days. Loud noises can actually stop labour and cause problems. Keep her in a separate cage from other rats, in a warm place with dim light. Give her plenty of rags, shredded paper etc so that she can make a nest for her babies.

Rats can have between 2 and 21 babies per litter. This varies with age, diet, environment, and the number of litters that the female has already had. It is important not to breed a female before she is around 5 months old, but it is also important to breed her before she is 8 - 12 months old, if you intend to breed her at all. After that age, if a female has not mated, her hip bones fuse and could cause problems in a first time pregnancy. After this first mating, a female can have litters up to 18 months of age, but should have a rest of 4 - 6 months between litters to recover. Remember also that males should not be in with the females when they give birth. There is no danger to the babies, but as soon as the mother gives birth, she comes into heat again. Being pregnant at the same time as having to suckle another litter is too taxing for the mother.

1 day old: jellybeans!

5 days old: basic colour visible

Black DU Berkshire kitten at 5 days old
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