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:
Syrian 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 closer to 4 months old (males can be bred by 2-3 months of age). They should not be bred for the first time after 6 months of age, however.
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 syrian hamsters is 16-18 days (average is 16 days)
Litter size is quite variable, but typically there are 5-10 pups per litter (litters of over 20 have been reported).
Age of Weaning:
Syrian hamsters can be weaned at 21 days; this is a good age to separate male pups from the female pups.