In the days before and after parturition, the female hamster must not be disturbed: cage cleaning and handling the animal can lead to cannibalism of the neonates or to them being rejected. The gravid Golden hamster should be kept in a cage alone, while a Russian hamster can be left with the male, which helps to take care of the pups.
The mother must have an abundant supply of material to make a nest (paper handkerchiefs are recommended) and a sufficient store of food. The newly born pups should not be touched for the first 7 days of life. Females, especially if frightened or disturbed, slip their pups into their cheek pouches and then replace them in the nest shortly afterwards when they think the threat has passed. However, the pups are sometimes suffocated, particularly if the female is disturbed for a long period.
At birth the pups are completely helpless, naked and have closed eyes; they do, however already have incisors. Hair begins to grow after 9 days in the Golden hamster and after 3 to 4 days in the Russian hamster. Weaning occurs at 20-25 days in the Golden hamster and at 14 days in the Russian hamster, although the pups begin to eat solid food earlier. It is a good idea to leave food, such as moistened pellets, on the floor of the cage so that it is easily accessible; the pups must also be able to obtain water easily.
Young hamsters that are orphaned before weaning have no chance of surviving; attempts to entrust them to another nursing animal or to feed them artificially will be unsuccessful. Young Golden hamsters should be separated and housed individually once they reach 50 days old; if this is not done, they begin fighting and the first pregnancies occur among the young females.
Golden hamsters do not go into oestrus again until the pups have been weaned. Female Russian and Siberian hamsters go into oestrus 24 hours after delivery, but it is not advisable to breed them too frequently.
In the case of Roborovski hamsters, the pups are reared by both the father and mother which should not, therefore, be separated. Within a few days of delivery, the female can go into oestrus again and have up to four pregnancies in the reproductive season which is from April to September. The pups, which weigh about one gram at birth, open their eyes and ears at 2 weeks old and at 19 days are already weaned and ready to leave their mother. The female becomes sterile after 1 to 1.5 years. Roborovski hamsters are not very easy to breed in captivity. Although some couples reproduce without problem, in other cases the females never reproduce or begin to do so only at 7 to 8 months of life.
As far as concerns Chinese hamsters, it is unlikely that there will be problems with unwanted litters, since these animals are very difficult to breed in captivity.
