AFRMA

American Fancy Rat & Mouse Association

This article is from the Fall 1997 AFRMA Rat & Mouse Tales news-magazine.

Mouse Multiplication Mania

How fast can mice multiply? Start with 2 baby mice, one of each sex. At 6 weeks old the female can become pregnant. Gestation is 3 weeks, and under optimal conditions the female can become pregnant again immediately after giving birth. Assume a litter of eight, four male and four female, which are paired and bred when they are 6 weeks old. Theoretically you could get:


Too many mice!
WeekFemales  XMales  =BabiesTotal Mice
31102
61102
911810
1211818
1511826
18554066
219972138
241313104242
273333264506
3069695521058
331211219682026
3625325320244050
3952952942328282
4210131013810416386
45202520251620032586
48414141413312865714
518193819365544131258

Yes, that’s over one hundred thousand mice in one year!

Caution: don’t try this at home.

Challenge:
How many more weeks will it take before you have over 1 million mice?

See answer here (put mouse over underline):
You will have over a million mice in only 9 more weeks! *

Updated March 3, 2014