Hamsters are rapid breeders, with gestation times averaging just a little over a month. By observing the behavior and appearance of a female hamster, you will be able to recognize when she is pregnant and help her prepare for the babies.
Recognize when a hamster is pregnant by observing an increase in activity, especially in regard to nesting behaviors. Pregnant hamsters will begin to prepare the bedding area by adding more cedar chips to the existing nest. In addition, the female hamsters will also begin to hoard food, usually hiding it directly under the nest.
Observe any increases in weight gain in order to recognize signs of pregnancy. While a pregnant hamster may not show a bump in her belly until 4 or 5 days before giving birth, you should notice a rapid increase in the girth of the animal. This is usually caused by an increased appetite and should start just a few days after conception.
See whether your hamster is drinking more water than usual. Excessive thirst often accompanies pregnancy in hamsters, but it may also be a sign of gastrointestinal distress from fruits and vegetables as well.
Watch the hamster in question to see how she interacts with other hamsters in the cage. You will be able to recognize a pregnant female if she suddenly begins fighting with the others and protecting her nest. A pregnant hamster may also be more reluctant to let you handle her, and she may even bite you once or twice to let you know she is displeased and uncomfortable with being held.
See whether a hamster's nipples begin to protrude from her abdomen. This will occur about a week before the babies are born. The nipples should be clearly visible in all but the longest-haired varieties of hamsters, such as the dwarfs.
Make arrangements once you recognize that your hamster is pregnant. Isolate her from the other hamsters, and consider whether you will keep the babies or find homes for them once they are 4 to 8 weeks old. Remember that the offspring can mate when they are 8 to 10 weeks old.