Breeding & Mating: Initiate hamster breeding by placing a mature female into the male’s cage nightly during estrus. Estrus is the period of time when a female hamster will mate with a male and lasts roughly 12 hours. You will know the female is receptive if she stretches and splays her legs when you stroke her back. Estrus typically takes place at night and the pair may be lightly combative at the onset. If fighting continues for more than a few minutes or seems particularly rough remove the female and wait a day or two before trying again. Keeping an eye on the pair from a distance or remotely via camera is recommended. If mating occurs you can safely leave the pair together until morning, if not it's best to separate them and try another day.
Pregnancy & Gestation: The female hamster will appear pregnant 2 weeks after mating. Placing the mating cage in a quiet, isolated location is recommended because hamsters easily become stressed. Her interests may shift from running on her wheel to eating and resting during pregnancy. Nesting and grooming behavior increases before giving birth and the female may seem restless or startle easily. Gestational duration varies slightly by hamster type but expect a litter 18 to 22 days after mating.
Birth & Litter Size: Baby hamsters are called pups. A typical hamster litter will be 6 to 8 pups in size but can be as small as 3 and as many as 12 pups in size depending on breed. Pups are typically born a few minutes apart but may be up to 30 minutes apart as the female cleans the nest between births. Allow mother to take care of her babie's umbilical cord and adopt a hands off approach as much as possible. Do not open the cage or handle the babies until they are 2 weeks of age, unless necessary. If mother feels threatened in any way there is a chance she cannibalizes one or more of her pups. This can happen anyway so reduce the chance by leaving the litter alone.
Caring for Babies: Baby hamsters are born toothless and without hair until they reach 11 to 14 days in age. Mother will feed her litter at first until the babies begin drinking water(14 days) and eating food between(16-21 days) on their own. Pups will behave as a group and eat, sleep and play at the same time. Successful hamster weening occurs after 3 weeks and sexual maturity is reached between 6-7 weeks of age.
Hamster Sexing: To determine a hamster's sex hold them gently but firmly on their back in the palm of your hand with their back feet slightly higher than the front. They may struggle as you examine their genital area so hold them just above a table or hard surface to minimize the chance of being hurt by a fall. The genital opening of a female hamster is next to her anus while a male's genital opening will be a small distance away, roughly the width of your finger. Male hamster testes become visible as two hairless pink lumps on each side of the anus after roughly 5 weeks of age.
Signs of trouble: The female hamster will instinctively know what to do during and after pregnancy so the less you involve yourself the better. It may be tempting to watch closely or bring the kids around but if you do this you need to be extra careful not to do anything which might make the mother feel threatened in any way. The simple act of opening her cage or touching her pups may cause mother to eat one or more of her young as a result. This happens by instinct and is done to give the remaining pups a better chance at survival. Your best intentions may backfire so a hands off approach for at least two weeks before and after birth is recommended. Before breeding ask your vet what type of complications are common with your specific breed.
Tips for a positive outcome: Bring mom to the vet for a prenatal checkup before mating. Avoid stressing mom as much as possible from mating until two weeks after delivery. Don't change the bedding during this time. Have a second water bottle available to quickly swap with the first so that you don't have to return twice. Practice adding food to the hamster's bowl through the side of the cage, without opening the door. Use a cage big enough to allow a private area that is largely out of sight. Don't move or otherwise disturb the litter unless absolutely necessary. A small camera outside the cage is better than a big human next to it if you'd like to monitor the process. Trust that mother hamster knows what she is doing. When in doubt call a vet, otherwise enjoy your hamster miracle!