multiple births from one mating

Question
I have 6 female rats that I have had for about a year and inherited a male.  My busband put them together and yes you guessed it I have to many now. Anyway I have a question.  I have a dumbo that had a litter on March 31 of 2008 and this morning there were 8 more babies that just appeared.  I thought it was from a different mom but the one I thought was the mom  doesnt seem to be interested and the dumbo seems to be the one caring for the babies so I am assuming it is hers.  The male has been seperated from them since I found the first litter and I am wondering can a female give birth again so soon and from only one mating that I know of?

Answer
Did you remove the male after the birth of the first litter?  Rats go through a post partum estrus, which means they come into heat again shortly after giving birth and if the male is still in the cage, he will mate her again.  This second pregnancy usually has a longer gestation period than normal, usually between 26 and 30 days instead of 23, and this is likely what happened.  If her first litter is now 4 weeks old, I would recommend separating them from her so she can focus on her new litter in peace.  Also you may want to give her some puppy milk replacement to keep her calcium levels up; rats can quickly become hypocalcemic when caring for too many babies and a second back-to-back litter can be hard on her that way.

Good luck with your rats!

For more information about rats please visit my website at http://careguide.evergreenrattery.com