If you have a new hamster but don’t know its gender, you’re likely wondering how to tell males and females apart. You can determine the difference between sexes once you know what to look for.
Female hamsters have nipples on their bellies and a vaginal opening near the anus. They emit a smell when they go in heat every 3-5 days.
Males have large testicles and prominent scent glands, and you can see a penis located further from the anus. Female hamsters are usually bigger than males.
When Can You Tell the Gender of a Hamster?
In most cases, you can tell the gender of a hamster when it’s about one month old because it’s much easier to identify sexual characteristics as hamsters age and become sexually mature.
For females, this happens when they’re 6 weeks old, while males become sexually mature when they’re 10 weeks old. Before this point, hamsters look much the same, regardless of gender.
Inexperienced owners must wait until hamsters age and develop more noticeable sexual organs.
How To Tell if A Hamster Is A Boy or Girl
It’s easy to tell male and female hamsters apart once they’re old enough to develop sexual characteristics. If you’d like to attempt sexing your hamster, look for the following:
| Characteristic | Male Hamsters | Female Hamsters |
| Opening: | A penis opening near the tail-end, a fair distance from the anus. | A vagina close to the anus sometimes appears as if they’re touching. |
| Testicles: | Large testicles near the tail. They can sometimes be retracted and hidden from view. | None |
| Nipples: | None | Two rows of nipples on the belly. |
| Odor: | Normal | It can be foul-smelling when the female is in heat every 3-5 days. |
| Scent Glands: | Far more prominent than females, especially in dwarf varieties. They can appear waxy, oily, or yellow. | Normal, not very prominent. |
| Size: | Small to medium. Males tend to be smaller than females. | Medium to large. Females are commonly larger than males. |
| Temperament: | Calm, relaxed, laid-back, and sometimes less willing to be handled | Aggressive, characterful, boisterous. Quite happy with human interaction. |
Let’s take a closer look at each characteristic in more detail:
Openings
Both male and female hamsters have openings, but they look different.
Males have a penile opening, whereas females have a vagina. The easiest way to tell the difference is by assessing the anogenital distance, which is the distance between the anus and genitals.
The distance is much shorter in females, making distinguishing between the anus and vagina more difficult. The space is twice as long in males.
Testicles
Male hamsters have testicles that appear around the tail area.
They often appear large compared to their overall stature, causing many owners to mistake them for cancerous growths. However, they’re normal if the hamster is otherwise healthy.
Hamsters’ testicles rarely have hair, although small strands may appear around the area. Long-haired hamsters will have less noticeable testicles because their thick coats cover them.
When looking at a male hamster from above, its rear end will protrude slightly and appear triangular compared to a female’s round and smooth bottom.
Testicles are rarely noticeable in hamsters before they’re a month old. Hamsters can also retract their testicles, making them almost impossible to spot.
However, as the hamster grows, the testicles become more noticeable.
Nipples
Female hamsters have two rows of nipples opposite each other along their bellies. They should be easy to spot unless you have a long-haired hamster whose nipples are covered by a thick layer of fur.
If you can’t see them, run your finger along your hamster’s belly to check for a row of soft protrusions.
The nipples become more prominent as female hamsters age. They’re easy to spot on pregnant hamsters or hamsters who already have a litter of babies, while male hamsters don’t have nipples.
Odor
Female hamsters have a noticeable odor when they’re in heat.
This biological process occurs every 3-5 days and lasts 12 hours. Many owners describe this odor as intense and unpleasant, like a musky, burnt smell.
Female hamsters also produce a thick, white discharge around the genital area. The discharge and smell are normal and signify that the hamster is ready to mate.
This smell and discharge should disappear once the hamster’s out of the heat.
Scent Glands
Male dwarf hamsters have noticeable scent glands that look like yellow patches of fur.
You may also notice oily stains around the glands caused by their secretions. Veterinary Practice News explains how they often appear greasy or waxy.
Syrian hamsters also have scent glands but are on the flanks instead of their bellies. Like dwarves, they’re more prominent in males than females.
You may need to part the fur to get a better look, as the hamster’s coat sometimes hides them.
Size
Female hamsters are larger than males. This is because male hamsters scavenge and forage for food, while females remain in their burrows and have babies.
The additional weight enables them to give birth to healthy litters. Captive hamsters share the same genes, so females are naturally larger than males.
While this won’t help you sex your hamster in isolation, it can help you choose a hamster from a litter.
Temperament
You can tell males and females apart by their temperament. While this isn’t the most accurate way to sex a hamster, monitoring their personality is useful.
Females are considered more aggressive than males but are also more boisterous and characterful, which many owners enjoy.
Males are calmer but can become ghost hamsters, preferring to hide until their owners have gone to bed. Of course, all personalities are unique, but this is common.
Can Hamsters Change Their Gender?
Hamsters can’t change their gender because they’re born with a particular set of sexual organs and retain them throughout their lives.
Your hamster may “change” gender if you’ve incorrectly sexed it, but this is down to human error rather than its biological makeup changing.
Also, some male hamsters retract their testicles at first, making them look like females. That’s why it’s easy to believe that a female hamster has suddenly become a male.
It’s common to get the gender wrong while hamsters are young. After a month or so, most owners have a more accurate gauge of gender when the sexual organs are more prominent.
Can You House Male and Female Hamsters Together?
The Michigan Humane Society recommends keeping hamsters apart, regardless of their gender.
Males and females must never be kept in the same cage, at least not permanently. Otherwise, you’ll end up with many offspring throughout their lives.
According to the MSD Veterinary Manual, female hamsters become aggressive when they mate. Similarly, genetic defects are associated with hamsters with no known genetic background.
When female hamsters become pregnant, they give birth within 16-22 days. Depending on when the female goes into heat, she can become pregnant again 24 hours after giving birth.
The only hamsters who can live together are dwarves, but only if they’re from the same litter and have cohabitated since birth. They must also be the same gender, or they’ll continuously breed.
Even though dwarves are more suited to living in pairs than Chinese and Syrian hamsters, there’s still a high chance they’ll fight. It’s rarely worth the risk of keeping two hamsters at a time.
When sexing a hamster, hold it under its front legs and turn it on its back so you can observe whether it has a vagina or testicles.
If you see nipples, you have a female, while prominent scent glands indicate a male. Once you’ve accurately sexed a hamster once, it’ll become easier.
