A Note About Breeding:
Breeding your gerbils is not a decision to make lightly and you absolutely must consider what you will do with any babies that result. Most pet stores have established suppliers already. You should also carefully consider the temperament and health of the gerbils you are breeding. I do not advocate breeding gerbils for the average owner, but the information here may be helpful if you find yourself with a pregnant female by accident, or perhaps from the pet store.
Age of Sexual Maturity:
Gerbils may reach sexual maturity around 9-12 weeks of age, though there is some variation.
Female gerbils come into estrus (heat) every 4 -6 days (this is the time they will be fertile and receptive to a male).
Length of Pregnancy:
The gestation period of gerbils is usually 22-27 days.
Note: gerbils can breed shortly after giving birth. If they breed while already nursing a litter, the gestation period can be anywhere from 28-47 days).
Litter size is usually fairly small; typically there are 3-7 pups per litter.
Age of Weaning:
Gerbils can be weaned at 4-5 weeks but can be kept with mom until they are about 6 weeks old. 6 weeks is also a good age to separate the male pups from the female pups.