Breeding & Mating
To breed your hamsters, introduce the female into the male’s cage every evening for four days during her estrus. Estrus is the period of time, usually about 12 hours long, when the female will mate with the male. The female will be receptive if she flattens her body and splays her legs when you stroke her back. Estrus occurs during the night and there may be some minor sparring and tussling between the male and female. Be ready to remove the female if she doesn’t settle down soon and appears to only want to fight with the male. It also helps if the male has an easy to get to place to hide from the female. If mating occurs, keep the pair together for several hours or even overnight.
Gestation & Litter Size
The pregnant female will appear fatter 2 to 3 weeks after mating. She may spend less time wheel running and more time eating. Pregnant females tend to become more aggressive as their due date approaches. The gestation of your hamster varies by type but expect a litter in 18 to 22 days. The hamster litter size is usually in the 4 to 6 range. It can be as few as 3 and as many as 12 depending on the type of hamster. The mother could have many babies but may not raise them all to weaning and it is possible that she may eat some of them.
Nest building activity increases as does eating, grooming, and digging before giving birth. The female will seem restless and may startle easily. She stands erect as the babies (pups) are born and will sever the umbilical cord on her own. The pups are born at 10-30 minute intervals and the mother will sleep or tidy the nest area between births. The mother will then hold and clean her pups. Make sure she had adequate food and water since she will be very hungry and thirsty after the birth. Do not open the cage to look at the babies for at least two weeks. The mother may interpret this as a threat and eat their young if the cage is disturbed.
The babies will begin drinking water at 13-15 days of age and eating food between 16-21 days. Make sure they can reach the water bottle and the food dish. Pups huddle with each other, move around together, and eat together. They also play fight. The babies can be successfully weaned from the mother after about 3 weeks. They will be sexually mature at 6-7 weeks of age.
Grasp the hamster firmly around the body and lift him upright and tilt his body slightly backwards. The hamster will not be fond of being in this position so he will struggle but don’t worry, you are not hurting him. Look at the genital area. Females have the genital opening and the anus close together. Males have the genital opening separated from the anus by a distance approximately equal to your forefinger. When you hold a male older than five weeks upright, the testes fall down to the edge of the body forming two distinct pale pink lumps on each side of the anus.