The best time for hamsters to have offspring is when they are between 10 weeks and 15 months old. Breeders use pairs with 1 male and 1 female, as well as groups of hamsters with 1 male and multiple females. Breeding of hamsters is best left to experienced breeders because hamsters (particularly females) can become aggressive during mating. Also, a number of genetic defects are associated with various types of hamsters, so breeding hamsters without having knowledge of their genetic heritage is not recommended.
Pregnancies usually last from 16 to 22 days, depending on the type of hamster. (Syrian hamster pregnancies tend to last 16 to 17 days.) You may notice a slight increase in girth or a larger abdomen in a pregnant female a few days before she gives birth. As pregnant hamsters approach the time to deliver the litter, they may become restless and active and may have vaginal bleeding. When they are ready to give birth, provide them with nesting material. This helps them feel secure and lowers the chance that new mothers will abandon or eat their offspring. Mothers and litters should not be disturbed for at least 7 days after the offspring are born, especially if the mother has never given birth before. Fostering abandoned offspring onto a different mother is rarely successful. Limit your activity around the cage to providing food and water as needed.
Normal litters contain 6 to 8 pups, and offspring are weaned after about 21 to 28 days. The pups are hairless and their eyes and ears are closed; however, pups have their front teeth (incisors) at birth. In most cases, it is safe to slowly begin handling the pups when they are about 7 days old. Solid food moistened with water can be offered to pups starting at about 10 days of age. Food and water should be located close to the floor within their reach.