Great fitness of rats 🐀

Kingloui  -  October 23, 2020

Female rats get their puberty after 4 months. The gestation period is less than 30 days.
Assuming, after pregnancy, they become pregnant again right away, on average eight baby rats are born in one litter and four of them are female,

How much progeny will an adult female rat have after one year starting on the 1th of January?

The first litter of the mother rat sees the world for the first time on the 30th of January.
(Obviously, their is no pressure by nature, all rats live healthy.
The children of the male rats are neglected as it’s hard to assign them to the right individual)