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Physical Differences

The easiest way to tell the difference between male and female hamsters is by the nipples. Females have nipples and males don’t.
When it comes to reproductive parts, there are two ways to tell a male and female hamster apart. The first is that the male will have quite large testicles and their bottom will be longer than the females, this is most obvious in syrians and chinese dwarves. The second and more useful in the smaller species, is the distance between the genital parts. Females have a vaginal opening very close to the anus. In males, the penis is further away from the anus.

Both male and female hamsters have scent glands, although the males’ are often more visible.
Female hamsters will go into heat every 4 days. During this time, they can produce a strong smell. It is important to note that hamsters do not have a period. If there is ever blood coming from your hamsters vagina, it is likely an infection (Pyometra) or tumor which requires a vet visit as soon as possible.

Personality Differences.

There is no scientific evidence to show what type of personality a male or female hamster will have. This guide is based on general stereotypes and the common differences noted by hamsters’ owners. Just like many other animals, every hamster will have it’s own unique personality traits. Some contributing factors may include where the hamster was bred, it’s age, it’s environment and how often it is handled.

Female hamsters are generally more active than males. If you plan on owning a female hamster, especially a Syrian, it is extra important to ensure they have a cage much larger than the minimum requirements for the species. They also need lots of enrichment as they can be erratic and “highly strung” with destructive personalities. Male hamsters tend to have a calmer personality and can be easier to handle. For this reason, males can sometimes be tamed quicker than females and may be a more suitable option for beginners.


Hamsters can hear very well. They have two prominent ears that sit on the side of the head. We as humans can hear sounds between 16 Hertz and 20,000 Hertz.  Hamsters can hear sounds between 80 Hertz and about 45,000 Hertz. They “talk” among themselves with sounds between 32,000 and 38,000 Hertz. These are sounds we don’t hear.

The ear shape of the Syrian and Russian dwarf hamster is different from that of the 3 other domesticated hamster species. There is a fold in the earpiece so that they can close the earpiece. Syrians and Winter Whites put their ears up when they want to hear sounds properly. This is the case when they are curious and stand on two legs. The ears are then upright. In resting form, the ears close, but are still partly open. This is because in harsh weather conditions in nature it can be quite cold, and the ear entrance is protected against cold air. The ears are completely hairy. There are hairs on the front of the ear so that they are somewhat covered. But they have a fold of skin on the inside with which they can narrow the ear entrance.

Using the ears

The ears of the hamster are on the side for a reason. As a result, sounds do not arrive in both ears at the same time. These minuscule differences allow them to locate the direction of the heard sounds.
Hamsters use their ears in conjunction with other senses such as the whiskers and the eyes. They feel with the whiskers that make up the substrate, but they can also hear this from the different sounds.


Hamster Whiskers.
Like many animals that do not see very well or are mainly active at dusk/dawn or at night, hamsters have whiskers. Whiskers are used in navigation and foraging for food. The whiskers are senses that we as humans find difficult to imagine. You can compare the whiskers to the tips of your fingers. When you close your eyes and move your fingers over an object, you feel the material and form an image of what the object looks like. You use your memories to identify it. Hamsters do this with their whiskers. However, whiskers are much more sensitive than fingertips.

A hamster has about 60 whiskers around it’s snout and these whiskers can move independently. They also move independently of the muscles in the head and jaw. Most whiskers are on the sides of the snout, but a few are just above the hamster’s eyes facing upwards. The whiskers on the sides move back and forth between four and twelve times per second. This action is called frisking. This motion allows them to scan their environment. The sense of touch in combination with memories ensures that the hamster knows what it is feeling.

But this isn’t all a hamster’s whiskers feel. They can also observe movements of the air – not only air currents, but also sound waves. It is suspected that by noticing the small vibrations, sounds can be converted into images, similar to a type of sonar. Long whiskers pick up low frequency vibrations and short whiskers detect the higher frequencies. The combination of touch and hearing sound with their whiskers allows hamsters to identify materials. If you place your hand in front of your hamster, it may tickle you with it’s whiskers. This is the hamster’s way of investigating who you are.

Deformed whiskers in Rex and Hairless/ Nude hair varieties.
The Campbell’s dwarf hamster has the Hairless mutation, and the Syrian hamster has both the Rex and Hairless mutations. These varieties of hair cause a change in the shape and length of the whiskers. The whiskers of a Rex hamster are shorter and curled. These whiskers do not function as well, but are still useful in practice. If such a whisker is very short or presses against the body, then incorrect vibrations are measured and eventually no longer interpreted by the hamster.

But if the whisker doesn’t press against the body and isn’t short, then it can pick up vibrations from touch despite being curled. Only the tactile power is limited. Fortunately, naked/hairless Syrian hamsters are not widely bred due to being unethical. Nude/hairless as the name suggests are actually not completely naked/hairless. The hamsters have some short hair on their head and small hairs elsewhere on the body. They also have curved whiskers and eyelashes. The whiskers are very short, but also perceive as normal.

How this effects Hamster Care
Touch is one of the hamster’s most acute senses, so it’s important that we appeal to it as much as possible. This is yet another reason why small plastic pet shop cages are unsuitable. They are colourful and easy to clean which encourages humans to buy them, however, they offer very little enrichment for your hamster. Plastic is not a breathable material and the hard, smooth texture is not interesting for your hamster to
explore.The base tray, house, wheel, tubes are all made of the same texture and so the hamster becomes bored quickly.

Different textures are ideal; whether it’s a digging material, nesting substrate, or other natural item such as cork, wood, slate or hay. The more variety we can pack into our hamsters’ enclosures, the more they can explore different textures. Introducing new items from time to time will help stimulate them and keep them active and happy. Try forage boxes, boredom breakers, cardboard boxes and tubes stuffed with tissue paper and treats etc. Your hamster will enjoy using it’s sense of touch to explore these new things.


Why do some hamsters have red eyes?
Hamsters can have a variety of eye colours from black to brown to shades of red and even pink. Some eye colours are very dark, so they appear black, but on closer inspection a hint of colour may be detected. A hamster’s eye colour is determined
by genetics. Their eye colour is linked to their fur colour. Generally, wild hamsters have black eyes, the other colours are various genetic mutations which have been bred into the species.
The red eyes of a hamster, are not really red! Red eyes are actually transparent! The red colour that we see is the colour of their blood vessels when light is reflected inside the eye.

Are red eyed hamsters blind?
No. Red eyed hamsters are not blind. However their sight is a bit different than hamsters with black eyes. Normally, the black (or other dark colour) of the eyes have pigment which absorbs some of the light entering the eye. Due to red eyes actually being transparent, they do not have any pigment to absorb any of the light, meaning more light scatters in the eye instead of being focused on the best spot for viewing.
Because of this, hamsters with red eyes see less sharply than hamsters with black or darker coloured eyes. Red eyed hamsters also take longer to get used to the dark. Their eyes can take longer to adjust to the lack of light in their environment. Hamsters do not rely very heavily on their sense of sight, and so this slight difference in sight for red eyed hamsters does not impact them negatively in any way, especially as a pet in captivity.

Are red eyed hamsters albino?
No, a hamster with red eyes would be similar to a human with blue eyes. It is simply a genetic mutation and their red eyes are not associated with other characteristics of the albino condition. True albino hamsters do exist, but only in the Campbell’s dwarf species. They not only have red eyes, but are unable to produce pigment over any part of their body, so they will also have white fur and very pale pink skin.

Are red eyed hamsters unethical?
As mentioned previously the cause of red eyes is simply a genetic modification. There is nothing wrong with the hamster and they can live perfectly normal lives. For this reason there is no evidence to say a red eyed hamster is unethical. However, you may be able to spot an unethically bred hybrid dwarf hamster easier, as red eyes do not exist in purebred winter white hamsters. So any “winter white” with red eyes is in fact a hybrid dwarf.

Although red eyed hamsters can be as perfectly healthy and happy as any other hamster, they are unfortunately much more unpopular than their dark eyed relatives. Many people have a negative association with red eyed animals, with some claiming they are “more aggressive” or “evil”. None of this is true. However, it does have a negative impact on red eyed hamsters being adopted, and so, unfortunately, many red eyed hamsters take a long time to find their forever home.


Disclaimer: Hamster Info Ireland does not support or condone the unethical breeding of hamsters. This information is given for the purposes of education and awareness only.

Ethical breeders work hard to better the species and breed for health and temperament first and foremost. They put in huge amounts of work into researching hamster genetics, health and behaviour and work are to improve standards of hamster care and welfare. It takes a lot of dedication, hard work and money, but breeding can be a vert rewarding experience when done correctly. Anyone who is interested in breeding hamsters should be prepared to put in the work, time and costs and work alongside other ethical breeders.

Hamsters from pet shop, backyard breeders or rescues should never be bred under any circumstances. It is vital that the genetic information and lineage of parent hamsters is known before any breeding is carried out. When this is not taken into consideration, hamsters can be born with terrible deformities and it completely goes against everything that ethical breeders stand for.

If you are unsure whether someone is an ethical breeder or a backyard breeder, make sure to ask lots of questions about their hamsters’ lineage. Ethical breeders should have no problem giving you this information and should be able to use the correct terms for the hamster coat colours and types.


Hairless hamsters are genetically bred, it isn’t an illness that can develop. There are people around the world that breed them on purpose. When the care a hamster receives has to change based on their genetics, those genes are deemed unethical to breed as they result in physical handicaps.

Hairless  hamsters have a much shorter lifespan than their furry counterparts. Their bare skin is more sensitive to irritation, this means paper bedding is necessary as wood shavings would be too rough on their skin. They also have a reduced body weight, and are more susceptible to environmental factors, they are less able to regulate body temperature for example. Hairless hamsters are also unable to lactate, so any females that carry a litter to term, are unable to rear them.

Although very rare, the majority of these hamsters can be found in America. An ethical breeder would never try to breed these genes, there is no advantage or reason for a hamster to have no hair.


Ethical hamster breeders spend years researching genetics and learning from other experienced breeders. Hamster genetics are extremely complicated, so breeding should be left to the professionals. Education is key, and so it is vital that anyone who wants to start breeding hamsters first studies under an experienced ethical breeder. They must learn how to properly and safely breed healthy, happy hamsters that will improve the species’ overall health, physical condition and temperament.
A thorough knowledge of hamster genetics is essential. We have previously discussed how breeding Winter White and Campbell’s dwarves together creates unethical, unnatural hybrids. Every dwarf hamster sold on Irish resale sites are hybrids, due to ‘backyard breeding’ hamsters from pet shops. Hybrids only exist because of human intervention. Once the hamster’s genetic line has been diluted, even just once, it’s impossible for that line to ever be pure again. This could eventually lead to the extinction of both purebred species.

Hamsters that come from pet stores are often from rodent mills. This means they are bred with whatever other hamster is available. Babies are born three weeks later, and then they’re allowed to breed again, and again. Unethically bred hamsters can have an array of neurological, temperamental and physical health issues. Ethical breeders are constantly striving to produce healthy hamsters with good genetics in order to better the species.

Temperamental Problems:

These can arise when untamed/unhandled hamsters are bred. These hamsters pass on their temperamental issues to their offspring, resulting in more aggressive or very timid hamsters. There have been cases where a hamster has become pregnant in the pet shop and sold before they give birth. The new owner hasn’t had a chance to bond with her hamster. The hamster will be very protective of her young, especially around new people. The babies will sense the mother’s unease and her timid temperament will be passed on.

Neurological Problems:

Problems that occur in the brain can be due to genetics as well as stress, and more often than not, both. Backflipping/Stargazing is a condition that causes a hamster to constantly stare upwards, sometimes so far that they end up falling backwards.
Tornado-ing is another condition which causes the hamster to spin constantly. Hamsters like this do not need wheels as they already run too much. Spinning such as this can cause issues like heart attacks in hamsters and requires careful management by the owner.
All these issues can arise from unethical breeding, stress, or both. If your hamster is exhibiting any of these behaviours, please get in touch, as we can help you with any changes that need to be made to your hamster’s enclosure and care. We will always recommend a vet visit.

Physical Problems:

  • Eyeless White Hamsters: This condition occurs when 2 banded or patterned hamsters are bred together without
    knowing the genetic background and whether they carry the white belly gene. The babies are born without eyes,
    sometimes they’re deaf and are pure white in colour. Most do not live long, approximately 9-12 months.
  • Hydrocephalus: A congenital disease that causes fluid to accumulate in the brain and can cause brain damage. The hamster has a noticeably different sized head with an obvious deformity.
  • Small sized Syrians: Unethical breeding can result in offspring being a lot smaller than the average Syrian. These often don’t live as long due to health issues passed on to them through their genes.
  • Spinal deformities: this is most common in dark greys and lilacs and is often caused by kinked tail. Dark greys and lilacs should only be bred by ethical breeders to ensure that the hamsters are of good health to prevent kinked tail and other spinal deformities from arising.

Raising a litter begins with the mother. Female hamsters need a certain diet for a healthy pregnancy and healthy babies. Pregnant females require extra nutrients and extras, which raises costs already.

Once babies are born, it is essential to continue with a highly nutritious diet to help her raise her young. Once the babies are a little older, they start to nibble on foods that mum brings to the nest, so depending on the number of pups, extra food again must be provided. As the pups grow, they will be consuming more food each day, and it is essential they have unlimited feed to allow them to eat what they want. Keep in mind that they will consume this extra amount of food likely until they leave for their new homes.

In conclusion, there is at least 75% cost increase per week to feed a pregnant mum/pups than feeding a normal adult hamster. This amounts to a huge monthly increase. Not to mention the increased costs of bedding on top of this.

Hamsters, when on the appropriate diet and care, usually have no issues. However, things can go wrong, and, in this case, they will need a vet. Hamsters are classed as exotic animals, so vet care is expensive. Just an average consult and exam can cost anywhere to €100, and if the hamster needs surgery or other treatment, this could easily amount to anything up to €1000 and more depending on the necessary action.

Usually with an average size litter (6-7 pups), total cost can break even, so any money made from the babies usually covers the food and bedding used during their care, also keeping in mind that any leftover is put straight back in to caring for other hamsters in the hamstery (toys, bedding, food, vet bills etc). When there is a large litter (12+) it can be a bit harder to break even, as there is almost double the amount of food and bedding used as there would be for a smaller litter. So usually, breeders break even or come in at a loss. Hamster breeding is a non-profitable hobby when done correctly.

Ethical breeders do not “expect” mortality rates but accept that they can and do happen. Sometimes it can be unpredictable, and pups may be lost and sometimes even the mum. By breeding pedigree and healthy hamsters, it is hoped to keep mortality rates to a minimum. Breeding unhealthy animals with unknown genetic history is always a gamble, which could produce pups that will have illnesses or pass away, so a higher mortality rate can then be expected.

So, for starters, the mum will need her own maternity cage. Another two cages are required to split the babies into male and female groups once they are old enough (and mum gets her own space back.) Once the babies reach maturity they might start bickering, so they will need to be split into their own cages if not rehomed yet. Depending on litter size that is a lot of spare cages.

Hamster breeding is extremely time consuming, especially once the babies need to be handled and cleaned. At first, only approx. 15-20 mins of handling should be done per day. More time is needed to clean out the dirty parts of the cage. As the babies get older, they will require almost daily cleaning due to there being so many hamsters in one cage, plus a minimum of 1-2 hours per day for handling them.

Every hamstery is different depending on the size the breeder wants. Some breeders only keep a couple of breeding pairs at any one time (3-4 hamsters). However, when more genetic goals or unrelated hamsters are needed, more hamsters are needed. The average hamstery has 15+ hamsters. Each of these hamsters will need its own appropriate setup and living conditions so a lot of space and cost is required. It is important to give female hamsters a break between litters and to retire them afterwards.

There are multiple genetic combos that can be done that a breeder should be aware of. However, there are a few combos that must be recognised before breeding begins, as they can be dangerous/lethal when put together. Pairing hamsters with unknown genetics are a high-risk gamble and is unethical.

Transport and education are ongoing, time-consuming thing. When breeders buy new hamsters to breed, they must organise transport to get the hamster to them. If babies need to be moved, then transport must be organised.

Time needs to be spent reviewing potential new homes for the baby hamsters to ensure they are up to appropriate standards.

Education is a never-ending process, breeders should be open to learning new things as standards are always changing, it takes a lot of time to become confident and familiar enough to be an ethical hamster breeder.

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