A Note About Breeding:
Breeding your hamster 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 and there is no shortage of hamsters available. You should also carefully consider the temperament and health of the hamsters you are breeding. 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:
Dwarf Russian hamsters may reach sexual maturity as early as 4-5 weeks of age. However, females should not be bred for the first time until they are 3 to 4 months old (males can be bred by 2-3 months of age).
Female hamsters come into estrus (heat) every 4 days or so (this is the time they will be fertile and receptive to a male).
Length of Pregnancy:
The gestation period of dwarf Russian hamsters is 18-21 days.
Litter size is quite variable, but typically there are around 6 pups per litter (larger litters have been reported).
Age of Weaning:
Dwarf hamsters can be weaned at 21 days; this is a good age to separate male pups from the female pups.