Male vs female guinea pig guide

If you’re thinking of getting a furry little piggy pal, you may have come up with some questions for yourself to decide which type of guinea pig suits you best. 

Long-haired or short-hairedAbyssinian, Crested, American, Himalayan or a different breed?

But there’s also another important question to address before you choose your perfect guinea pig: male or female? (Or as they’re known in the guinea pig world….Boar or sow?) 

If you have no idea where to start on deciding whether they’ll be boys or girls or even a mix of both - don’t worry! Together with top guinea breeder Tara Richardson from the Kavee Rescue, we’ve answered every question you can possibly come up with….

Two guinea pigs together on a light red background

Males vs female guinea pigs - what’s the difference?

We may be a tad biased but, in our humble opinion, all guinea pigs are totally gorgeous! However, there are certain differences between guinea pigs dependent on their sex. 

For the avoidance of doubt, when we talk about ‘boars’ we mean boy guinea pigs and ‘sows’ are girls!

These are the main points to consider:

  • Size - Boars tend to be longer and heavier than sows. 
  • Lifespan - Male piggies also tend to live a little longer than females. Average lifespan for a boar is five to eight years whereas sows live between four to eight years. Their lifespan is, of course, dependent on diet, quality of life and general health too. 
  • Noise - Boy guinea pigs are generally a bit louder than girls - thundering around their cage and squeaking at the tops of their voices when they hear the fridge door opening. Girls tend to be a little more refined and low volume.
  • Personality - Every guinea pig’s character is unique, of course, but males tend to be more confident than females, who may be more nervous and take longer to form a bond with you. It can be fairly easy to form a close connection with a friendly, self-assured male piggy whereas females may seem stand-offish with us humans. (they’re just playing it cool, that’s all). However, the flip side to this is…
  • Aggression - Boy guinea pigs are generally more feisty and aggressive than girls. That’s because they feel more territorial and protective of their space which can lead to frequent spats with other piggies, who are ‘threatening’ their territory. Girl guinea pigs tend to be more chilled and less inclined to scrap - although that’s not to say that sows never fight because they can certainly stand up for themselves if required. 
  • Dominance - Regardless of their sex, all guinea pig pairs or herds have to establish a hierarchy with one piggy as the dominant top dog (or top pig). When your piggies are establishing their hierarchy, they will ‘rumble strut’ (walk slowly and menacingly around the other pigs, vibrating their bodies and making a loud, rumbling noise). They also do this when marking their territory and although you’ll probably notice boys doing it more often (as they’re more aggressive in general, as already mentioned), girls will also do rumble strut, especially when they’re in heat.
  • Cleanliness - Now, we don’t mean to be sexist; really we don’t. But can you guess whether it’s the lads or the lasses who keep their cage in a cleaner, tidier state? Yep, you’ve got it! Sows are generally much cleaner than boys, keeping their living space spick and span as possible by not spreading food all over the place. Male guinea pigs on the other hand? Let’s just say that you’ll be spending more time with a dustpan and brush if you choose boars, which brings us onto….
  • Smell - If you have a very sensitive sense of smell then it’s worth bearing in mind that boy guinea pigs tend to smell more than the girls. That’s because boars have a more active grease gland, which they use to mark their territory and can get a bit whiffy at times. For more insight, check out our blog post - Do guinea pigs smell?
What are the main differences between boars and sows? male and female guinea pig sitting next to each other on white background

How can you tell males and female guinea pigs apart?

The only way to tell if a guinea pig is male or female is to check their ‘bits’. However, it can be really tricky to determine a guinea pig’s sex at birth because their genitalia may be quite swollen at first.

Once the swelling eases after a few days, it can be possible to check but only if you really know what you’re looking for. This is the reason why so many people get it wrong and unwittingly put girls and boys in a cage together, resulting in unexpected pregnancies which ultimately leads to countless abandoned guinea pigs in animal rescues.

Tara explains: “A sow’s genitalia has a "Y" shaped opening and a boar’s has an "i" shape. The v shape in the Y is the vulva, the dot of the i shape is the penis.

It can be difficult to tell sometimes as they can be very small as newborns and genitalia can be swollen due to hormones in the first few days. However, light pressure applied to the abdomen just above the genitalia will usually make clear if there is a penis or vulva.”

How to tell male and female guinea pigs apart? Boars and sows anatomy difference infographic

Caring for male vs female guinea pigs: which are easier? 

There’s no straightforward answer to this question so let’s look at guinea pig care needs related to their sex. 


Male guinea pigs may need their cage cleaning more frequently due to their tendency to messiness as well as requiring more frequent washing and baths (here are some tips on how to give a guinea pig a bath) because their grease gland is more active and can cause nasty niffs. 

So how do you keep a grease gland clean?

Tara explains: “It’s advisable not to clean a grease gland too often and each piggy will differ depending on the amount of secretions produced. If you do need to clean this area, a good quality washing up liquid works really well. If the area is particularly clogged, Swarfega Original Hand Cleaner can be a good option too.

Dampen the area with warm water and rub a small amount of the soap into the grease until it breaks down the deposits, rinse really well under warm running water,  be sure to remove all of the soap before carefully drying with a clean towel.”

where is the guinea pig grease gland? Location of grease gland on boars bottom back

Another thing to consider is that (brace yourselves), when boars get, ahem, ‘excited’, they ejaculate, whether neutered or not. Their seminal fluid - or ‘boar glue’ - becomes rubbery and hard if left to fester in their fur and can also smell pretty grim. For tips on dealing with ‘boar glue’, check out this helpful video by Saskia at LA Guinea Pig Rescue. 

Also, as boars mature in age (generally over 2-years-old) they’re prone to faecal impaction, causing poop to get backed up in their rectum. Although this issue can be seen in females, it’s more common in males - and this is thought to be due to increased size of their testicles preventing faeces leaving the rectum. Faecal impaction can be painful as well as causing a pong so what’s the best way to treat it? 

Tara explains: “Soak your piggy’s bottom with warm water and very gently break away the impaction using your fingers at first. Virgin coconut oil can be used to help gently release the matter from the perineal sack and you can also leave coconut oil to soak a while on the skin, which can help soften and release deposits.

You can then use cotton wool and cotton buds to gently remove anything stuck to the skin. If the impaction is bad, cotton buds can be used to gently sweep the contents out of the sack. Cleaning may have to be undertaken in several sittings - never use anything sharp and always be gentle.

The skin in this area is delicate and sensitive. If it causes your guinea pain and doesn't soften and break away with coconut oil, it’s important to see a vet.”

quick guide to male guinea pig boar care faecal impaction piggy health


Female guinea pigs are more prone to urinary tract infections (UTIs) which can be fatal if left untreated. These UTIs can lead to the development of ovarian cysts, which are most common in sows aged between 2 to 4 years old.

Signs of UTIs include weight loss, lack of appetite, lethargy, crying when urinating and blood in the urine.  If you notice any of the symptoms we've listed, you’ll need to take your poorly piggy to the vet where they will do tests and take an X-ray to diagnose the problem.

signs of UTI urinary tract infection in female guinea pig sows infographic health care

Then there’s your sow’s reproductive system to consider. Female guinea pigs can become pregnant at just a few weeks old if they’re left with a boar who hasn’t been neutered. 

Both males and females can mate from about 2-months-old but for some, it may be even younger. Females can be fertile or ‘in heat’ every two to three weeks. 

You may be wondering whether sows bleed or have periods. The answer is that no, female guinea pigs don’t have periods. If you notice that your guinea pig is bleeding, you should get them checked out by a vet as a matter of urgency. 

Do male and female guinea pigs have different diet needs?

While every piggy thrives with a diet rich in fibre, fresh leafy greens, and safe veggies, there are certain foods that can meet the specific needs of your sows and boars.

At Kavee, we’re always looking for ways to simplify the life of pet parents everywhere. That’s why we have created treat trays that specifically address the different health needs of your boars and sows (but that everypiggy can safely enjoy!).

Let's have a better look to find out what are the differences!


As we mentioned before, boars tend to be smellier than sows due to their active grease gland, used to mark their territory. This isn’t just a problem for your poor nose - the smell can also attract parasites!

You can alleviate the strong smell of boars by feeding them peppermint, which is also a natural repellent to lice and mites. Birch leaves can also assist with making your boys less stinky, and are great for regulating a piggy’s kidney functions. 

Moreover, boars can be more territorial than sows and are not afraid to get into a fight. So it’s important to enrich their diets with foods that help them keep their strength up. Courgette is a great veggie to fight arthritis and reduce muscle cramps. 


Sows are more prone to UTIs, and so should be fed foods that can aid with the prevention of this infection. Chamomile and hibiscus are two plants that are greatly beneficial for female piggies, as they directly reduce the chances of UTIs. And that’s on top of being anti-inflammatory, anti-bacterial, and anti-spasmodic!

Nettle leaves are also another food that can benefit the reproductive system of sows, and that’s also great for preserving the bodily functions of piggies.

Another thing to keep in mind is that female guinea pigs tend to have higher cholesterol levels than male piggies. Celery stalks do a great job at reducing cholesterol and even support their metabolism.

Guinea pig being hand fed a leaf by a person

Choosing a cage for male or female guinea pigs: any differences to consider? 

As we’ve already explained, boars are generally slightly bigger in length and heft than sows. Also, as already mentioned, boys can be a bit more aggressive towards each other if they don’t have enough room or territory to make their own. 

So it stands to reason that they need a little more living space. That said, here at Kavee we believe that the minimum cage sizes advised by animal welfare organisations are far too small for both sows and boars, seriously reducing their quality of life. 

The current general guidelines are that two sows require a cage with 8 square feet of floor space and that two boars need 10 square feet. However, here at Kavee, we always advise piggy parents to buy as big a cage as they can afford for their guinea pigs so that they have plenty of room to zoomie and popcorn to their little hearts’ content. 

In our opinion none of the standard pet shop cages are large enough for either sows or boars. Here at Kavee, we recommend buying modular C&C cages of the following sizes:

Two sows - a cage at least 10 square feet which is a 2x4 C&C cage

Two boars/three sows/one neutered boar and two sows - a cage at least 12 square feet which is a 2x5 C&C cage

Four sows - a cage at least 14 square feet which is a 2x6 C&C cage

But always buy a bigger cage if you can! And if you have an even larger herd, you can expand and modify your C&C cage as much as you require in order to give your piggies the best quality of life possible. To view our full range of C&C cages that are available with dividers to separate your piggies, click here.

examples of C&C cage sizes for 2 guinea pigs 3 guinea pigs 4 guinea pigs boars and sows


Can males and female guinea pigs live together? 

As we’ve mentioned, girls and boys can live harmoniously together - either in pairings or in a herd consisting of multiple females and one male.

But (and this is a very big but!) you simply cannot house a boar and sow together if the male hasn’t been neutered or the sow hasn’t been spayed because of the risk of unwanted pregnancies. 

You may be shocked to learn that female guinea pigs can become pregnant very early on which means that boy and girl guinea pigs should be separated from three-weeks-old.

But vets generally advise against individual guinea pig owners attempting to breed guinea pigs. Not only can pregnancy and birth be very dangerous for sows, caring for a lactating sow and her newborn pups is a huge responsibility and not one that should be attempted by inexperienced breeders. 

As Tara explains: “Guinea pigs are born precocious. This means that they are fully developed, their ears and eyes are open, they are covered in fur and can get to their feet immediately and begin feeding on solid foods within 24 hours. Because they are born at a more advanced stage than other rodents, pregnancy lasts longer, putting more strain on the mother’s body and depleting her essential stores of vitamin c and calcium amongst other things. A drastic drop in these nutrients at birth is what can cause potentially fatal pregnancy toxemia. 

As pups are large in comparison to their mum’s body, birth is difficult and there’s a higher risk of both stillbirth and death of the pregnant sow.”

It’s worth knowing that whilst sows can be spayed and boars can be neutered, neither surgery is risk free. Guinea pigs are tiny, fragile little animals after all. Even if surgery goes well, recovery can be arduous.

Can you understand why single sex pairings and herds are the most popular choice for guinea pig parents?

Can males and female guinea pigs live together? two guinea pigs sitting together outside

Can male and female guinea pigs have supervised playtime together? 

By placing boars and sows together - for floor time or playtime in the same cage - you are playing a dangerous game! Sows can become pregnant VERY quickly and so even if you’re keeping a careful eye on things, you run the risk of unplanned piggy pregnancies.

boar and sow together on a pink background

Can male guinea pigs live in the same room as females?

You may be wondering if it’s possible for boars and sows to live in separate cages in the same room or whether it will cause them distress.

Tara explains: “It can be possible for the two to live in the same room but success is very dependent on numbers and on the guinea pigs’ personalities and bonds.

When a sow comes into heat it will be impossible to protect the boars from the scent, if the boars have a fragile bond, this can cause them to fight, if you really must house them in the same room, housing the boars above the sows tends to be most successful but ideally, they should be in separate rooms as it is never worth risking the boars’ bond.

Once broken it can be impossible to reunite them. Even if your boars are neutered, they will still fight over sows in heat and the situation can soon become fraught.”

 example on how to separate male and female guinea pigs 4x2 C&C cage double stacked two tiered setup

So how should you care for your female guinea pig who may be in heat?

Tara explains: “Most sow’s estrus cycles (when they are fertile) are short. Between 2 to 8 hours is normal and many people will miss this, especially if it occurs overnight, however some sows can become grumpy, restless and hormonal.

If they prefer not to be handled then be kind and leave them be. Foods rich in Vitamin C can help with hormones and foods such as sweet peppers or mandarin oranges always go down well at this time.

A sow in heat will often chase and mount their cage mates but this is perfectly normal behaviour and you shouldn't be concerned. The best way to keep a herd of sows settled and balanced is to house them with a neutered boar.” 

Guinea pig herd size for males and females - which is best? 

As we’ve already mentioned, guinea pigs are very sociable creatures who simply cannot live alone. If left in a cage on their own, a guinea pig can get very lonely and depressed, which may lead to them refusing to eat, losing a lot of weight and becoming seriously ill or even dying. So NEVER take on only one guinea pig - they must always have a buddy!

The simplest - and most common way - to keep guinea pigs is in single sex pair, so two sows together or two boars. Siblings, a mum and daughter or father and son work well as pairings as they’re already bonded. You can pair a boar and a sow together but they must be neutered first to avoid unwanted pregnancies. 

Boys tend to thrive most in single sex pairs - add one or more extra boars and you risk breaking up that bond, which can result in dominance struggles, frequent fights and general unhappiness within the herd. Of course, there are exceptions to this rule and you may well find that a larger group of boars can live together in perfect harmony but we’d generally advise against testing this out because if your herd does not get along, you’ll have to split them up and find space for another cage. Rescues often report that males are overlooked at rescues because people want to adopt larger groups, which usually means taking on girls, not boys. 

Girls do well in pairs, providing they’re well bonded, but they can also exist happily within a larger herd, either with more females or a group of girls and a neutered boar. If you’re planning a herd of three or more, don’t be tempted to add more than one neutered boar to the mix. As the boar will always assert dominance over the sows in his herd, even if neutered, it can lead to conflict if another boar is introduced into the mix.

If you have an all female herd, you may notice that the hierarchy changes over time, with the piggies fighting for dominance from time to time. This is absolutely normal and the guinea pigs will generally work things out between themselves. However, sometimes a herd of sows simply doesn’t get along. If you notice your group of girls nipping, biting or injuring each other, you will have to step in and consider splitting up the herd.

examples of herd sizes of guinea pigs males and females boars and sows

What are the benefits of adding a neutered boar to a herd of sow guinea pigs?

Tara explains: A neutered boar will be head of the herd, you will still have a matriarch and pecking order amongst the sows. Neutering a boar doesn't change his behaviour in any way, he will still display mating behaviour and mount the sows when they are in heat, this means that there are far less squabbles amongst the sows, in general as well as during estrus.

He cannot reproduce but he can and will "mate" the sows when they need him to, he will naturally go to them and they will be satisfied by his advances thus creating a calmer environment, as the sows won't be mounting and chasing each other causing tempers to become frayed with unwanted advances. He will be a busy boy taking care of his sows and this type of group is usually the most tranquil for both the sows and the boar.

An important note to add is that even when a boar is neutered, there must only be one boar per herd of sows. As mentioned before, neutering doesn't change his behaviour which includes aggression toward other boars, neutered or intact.
two guinea pigs sitting together

So what is the right guinea pig herd size for me? 

This is very much a personal choice based on the space available to you along with how much time you have to devote to caring for your guinea pigs. It’s also important to consider the financial aspect of being a guinea pig parent. The more piggies you adopt, the more fresh veggies, hay and vitamin C pellets you will need - as well as potential vet fees if any of them get ill. 

Also, if you decide to keep a bigger herd and then end up separating your piggies because they don’t get along, you’ll need to be prepared to shell out for more cages and bedding.

For more tips on the cost of keeping guinea pigs, check out our blog guide, ‘The real and shocking cost of owning guinea pigs’.

boar and sow guinea pig on a white background


We hope that you have more idea of the differences between sows and boars - and are a little closer to knowing whether boys or girls (or a mix of both) will suit you and your lifestyle best. Whatever way you decide to go, one thing is certain - becoming a guinea pig parent is a hugely rewarding experience and will bring you endless joy!


Guinea pig careGuinea pig health

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