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Do Hamsters Have Menstrual Cycles?

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Like all female mammals, your female hamster has a regular reproductive cycle that allows her to get pregnant and have litters of babies. Women have a menstrual cycle marked by monthly vaginal bleeding, but hamsters have the estrus cycle up to seven times each month. Estrus is distinguished by a whitish discharge, not by the bleeding associated with a woman's menstrual cycle.

Sexual Maturity

Your little friend will reach sexually maturity when she is just 6 to 7 weeks old, according to "The Hamster Handbook." However, her individual species may determine when she actually begins heat. For example, a Campbell's dwarf hamster who is raised only with female relatives matures and grows more slowly than one who lives with unrelated male hamsters. Meanwhile, female Syrian hamsters reliably reach maturity and are ready to mate by 45 days old, regardless of whether they are raised with male hamsters.


When your hamster enters her estrus cycle, she goes into heat and is ready to mate. One out of every four days, she will enter estrus. Since she is nocturnal, her estrus occurs at night and will last 12 hours. During this time, she is usually receptive to male attention. When she is not in estrus, your little female may be hostile to any male hamster who comes near her. The estrus cycle continues until your pet becomes pregnant or too old.

The Morning After

If your female mates with a male during the night, the next morning you will notice that her vagina holds a creamy, semi-solid substance called a "copulatory plug." This substance is evidence that the male released sperm during mating. For the next five days it is normal for your hamster to excrete a thick, whitish substance.


The prime time for your hamster to have a litter is when she is 10 to 15 weeks old, according to The Merck Manual for Pet Health. The expectant mommy's pregnancy will start to "show" about 10 to 18 days after mating, and her gestation will last 16 to 22 days, depending on her species. Her belly will swell and she may appear particularly energetic or edgy as she gears up to give birth to a passel of six to eight pups. She may also have some bloody discharge before the pups are born.


Bloody secretions are not common during a hamster's estrus, although a drop of blood may visible in some cases. If you notice consistent bleeding from your hamster's vagina or rear area, contact your vet immediately, as it may be a sign of serious illness or internal injury.