A Comprehensive Guide to Guinea Pig Boars

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Mar 10, 2009
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I Myths and misconceptions
II The different ages (including teenage)
III What do boars need? (List of boar dos and don'ts)
IV Companionship and ways to get safely bonded boars
V Neutered boars
VI Health problems and care
VII Conclusion

Boars are truly delightful and there are many owners who prefer them to sows, but they have sadly got such a bad press; not because of what they are but because they are far too often failed on all levels and repeatedly by sheer human ignorance and end up condemned to a single life or at the worst being euthanized for being aggressive.

I Myths and misconceptions

The key to any happy boar bond is mutual liking and character compatibility as well as plenty of space.

With that in mind, boars of all ages can be bonded and re-bonded at any stage of their lives.

An increasing number of good standard rescues offer dating sessions with rescue boars under expert supervision to allow your single, fallen-out or bereaved boars to have a say in who they get on with before they come home with a new friend.
This can take the form of speed dating to test for acceptance or residential dating where your piggy is meeting up to three rescue boars over the course of several days. Any successful bond is then tested for its stability before your boar comes home with a fully bonded new mate; the resulting bond is stable as any sow bond. This method also allows to bond boars of all ages. But because it is very time consuming, there not all that many rescues that can offer this service and those that do, often have waiting lists.

Boars don’t have to be litter brothers or need to be related; in fact, a larger age gap between a sub-adult and an adult boar is often an advantage as the hierarchy is not in question.

Thankfully it is another very much debunked urban myth that all boars fight!

If boars fight, it is usually the result of them being kept in too small a cage where they cannot get away from each other, as they would normally.
In fact, more boars than not make it to a hormonally much more settled adulthood together than not, and the odds increase massively if you take their needs in mind, and work with them instead against them.

Boars have a stronger smell than sows, but it can be kept in check to a good deal by regular bum washes (see the last chapter for boar care), daily poo patrol and twice weekly cleaning. You will need to air the house if the testosterone exhaust is running on full speed.
However, there is no such thing as a smell-free furry pet, and it is also worth keeping in mind that a lot of the testosterone and allergens are coming with the pee, which means that neutering is not removing all testosterone.
You will also have to live with the fact that hay and hay dust have a bad habit of getting literally everywhere…


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II The different ages

Some important biological facts
Boars start producing viable semen from 3-5 weeks onwards.

That is basically as soon a they are weaned. That is why they need to be separated from any sows at 3 weeks of age or you will risk a pregnancy. Since sows come into season from about 4 weeks onwards and again within hours of giving birth, it is vital that you sex your babies and remove any boars before birth or as quickly as you can in the case of a mis-sexed pair.

Sexual maturity refers to the descent of the testicles, which typically happens around 4 months of age coincides with the onset of the teenage and often with occurrence of strong hormone spikes.
Unfortunately, veterinary literature doesn’t make it clear that boars can procreate before their testicles have descended; this means that especially general vets not familiar with guinea pigs can give wrong advice.

There is no menopause or age when boars stop making babies or sows stop falling pregnant
, but the risks of miscarriage and death are the higher the older a sow gets.

The average life span of a healthy and well cared for guinea pig is 5-7 years, but a few can live up to 8-10 years.

Please always double-check the gender of your guinea pigs upon arrival! You can save yourself a LOT of trouble and headaches that way!

Our sexing guide also includes pictures of baby boars, boars with descending and fully descended testicles as well as neutered boars: Sexing Guide

The formative 'school' weeks (3 weeks - ca. 4 months)

It is generally overlooked just how important the weeks between weaning and teenage are.
This is the time where a youngster learns by following an older guinea pig around and by mimicking their behaviour, when they learn what and where it is safe to eat, how to drink from a bottle and all the nuances of the complex social interactive behaviour that guinea pigs have - i.e. they learn to master and successfully navigate their physical and social environment.

All guinea pigs of this age are desperate for company and for guidance. Pairing up a baby boar with an adult ‘uncle boar’ can give a little boy that essential guidance and socialisation. But not every boar will click with every baby although more will than not. However even when introducing a baby mutual liking is crucial for long term success when the baby goes through their own teenage.
However, while a boar may not vibe with baby boar #1 and he is very often head over heels with #2!

The tricky teenage months (ca. 4 months - 14 months)
It is the teenage months that are the reason why boars have a bad reputation. Not only do they mean that your cute little babies suddenly stop being cute and adorable, and suddenly turn into rumble-strutting hormone driven boars.

Since pet shops and for sale breeders are not interested and unable to personality match any guinea pigs they out up for sale; nor do they care about welfare requirements like large enough cages or very often competent and correct advice (it might deter impulse customers looking for cheap short-lived children’s pets with minimal cost small housing), the sad results are inevitable. Far too many boars are handed back or on with the advice that they are aggressive and have to be kept alone. Some pet shops even recommend keeping boars as singles because they don’t want to deal with the results of their shortcomings.

Please make absolutely sure that you NEVER go between riled up boars with your bare hands. Deep bites are an instinctive split second reaction to potential hostile movement. They are actually not aggression, they are made in defence, but they can cripple your hand permanently depending on what the teeth hit in that moment! Always use thick oven gloves and have them nearby if your boys are touch and go.

However, the teenage months are not a time when your boys are nonstop on the go. They are very much characterised by sudden huge hormone spikes which subside again.

The first big hormone spikes typically happen around 4 months when the testicles descend.
This process is usually completed at 6 months of age when the testosterone production is at an all-time high. Not surprisingly this is also the age when boars are at their most difficult to bond and re-bond with another boar.
The worst personality clashes usually happen at either of these periods; they are the times we see the most fall-outs and fights from boys who do not get on.

Another tricky period are the weeks around 8-10 months of age. This is less a period of hormone spikes but more a period of a sustained higher hormone level where the boys are constantly pushing the limits. Sounds familiar?
Fall-outs are actually fairly rare since the really bad personality matches have already clashed, but it is a period that will very often test you as the owner every bit as much as it does the boar bond!

And just when you thought that you were one of the lucky ones whose boars were swimming through the teenage months seemingly unaffected, your boys can wake up just when the other boys are out of the worst at 12-14 months…
This is a time when the quiet ones can have their big run-in and on occasion decide to disagree.

Short strong hormone spikes can continue into adulthood, but they usually don’t lead to fights and fall-outs. At the worst, a two day separation with a divider to allow the spike to settle down will do the trick. Allow the boars to reunite on neutral ground, but they should normally go back together again as if nothing untoward had happened.

You can find our full advice on the teenage months, how to evaluate whether a boar bond is dysfunctional or not and your various options after a fall out via this link here: Boars: Teenage, Bullying, Fighting, Fall-outs And What Next?

The adulthood years (ca. 15 months until ca. 4/5 years)

You will notice that by around 15 months your boys calm down a lot and become more staid. They are now adults.
The peak of their lives is at 2-3 years of age; this is the age when they are naturally at their strongest and heaviest.

This is the time when the more personable side of boars starts to emerge. Unlike sows, they tend to be more straight forward and care-free, and are often more accepting of cuddles.
It is for this thankfully longest age that many of our forum members love their boars and boar pairs so much; this gradual mellowing, the straight forward honesty and often a bigger sense for play and fun compared to sows, who are generally rather busy running the piggy world (including the boys)!

Boar personalities can be very varied. Not all are 'cuddle-uppers', but they have all got their individual endearing quirks and habits; and you can get hours of fun by watching, interacting and paying with them!
Enrichment Ideas for Guinea Pigs

The golden old age (ca. 4/5 years until end of life)
When boars reach 4-5 years of age, the testosterone is starting to fizzle out and they mellow a lot. Even the most dominant of boars are turning into nice chaps and can make perfect 'uncle boars' for fresh separated baby boars.

With the testosterone out of the way, they become also more accepting of other boars and company in general, and are much easier to keep in small groups as companionship outweighs youthful rivalry.

Just don't tell that to my neutered 5 years old Bryn Oscar, who had the best time of his life cutting a swathe through my older sows and playing one upboarship with my other 'husboars' when I adopted him as a stuck in rescue widower! He managed to pack a lifetime's worth of fun, escapes and pirating into the year he had to live; in fact, when he passed away, it was like he had been here a decade...
Whenever I remember him, I can only do so with a big grin! And that is not a bad legacy for 'surplus to requirement' pensioner adoptee is it?
Boars are never too old for company and can indeed gain a renewed zest of life from it!


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III What do boars need?

Guinea pigs are a ground roaming group species that doesn’t climb and that is not wired to live on their own. What all guinea pigs need is as much space as you can possibly give and company of their own kind. With boars it is also most helpful if you can prevent the top boar from becoming possessive.

Space, space and more space!
In order to allow boars to get away from each other, they should have a minimum of 2x5 ft space; ideally even more.

A 140x60 cm traditional cage or a 2x5 C&C grid cage is what many of our owners currently use for their boar pairs.
But you can afford a 3x4 or 2x6 C&C grid cage, please go for it because that gives each boy enough space for his own territory but is very easy to divide into two small welfare compatible single or pair cages that allow full interaction and communication on all levels through the bars for a ‘can’t live together but can’t live apart’ still bonded boar pair.
Guinea pig communication is complex and happens by scent (pheromones), body language and not just mainly by voice. Hearing each other but not seeing is less than ideal because it cuts out most of the vital stimulation through social interaction.

A C&C cage will also allow you to reassemble the cage in a smaller form but on two levels to provide to separate cages if you prefer to re-bond fallen-out boars with a new partner, be another boar or – after neutering and a necessary 6 weeks safety wait – with one or two sows each.

This guide here shows you very clearly what a difference space makes, even if you can upgrade just one size: Cage Size Guide
You can also see how guinea pigs can move when they have the space to do so in a video in our enrichment guide and why space really matters for their physical and mental wellbeing: Enrichment Ideas for Guinea Pigs

Respecting the hierarchy
Generally it is advisable to respect the hierarchy whenever you interact with boars. Always feed, treat, move, handle, cuddle and groom the dominant boar first. That can keep problems between the boars arising from a violation of the protocol to a minimum. Newly bonded, teenage or very dominant boars are generally the most touchy in this respect.

Enjoy a laid-back pair where this aspect is not an issue!

The ‘one of each’ rule
It is recommended for all guinea pigs, but essential for boars that they have each one of the same, ideally spaced as far apart from the same other item as possible.

This includes for a pair:
- 2 hideys with 2 exits (so no piggy can be ‘locked’ into a hidey)
- 2 water bottles
- 2 food bowls for serving 1 tablespoon of pellets and max. 50g of a balanced mix of veg and fresh herbs per piggy per day.
Please remove the bowls in between meals to encourage your boars to eat as much hay as possible, as that the key to long term health and longevity. Unlimited hay should make over 80% of the daily food intake.
Alternatively you sprinkle feed your guinea pigs for enrichment purposes so they have to look for their food all over their cage or their exercise run.
- Access to hay that cannot be blocked. Ideally you offer hay in two areas.
These measures help to minimise flashpoints for fights and bullying, including food bullying.

You will find that the cages and many hutches usually offered in pet shops either don’t have enough space for this or are very cramped once everything is in the cage, especially when your boys start growing!

‘Boarsonalising’ the new cage
Guinea pigs always need to re-establish the group in any new territory.

This means dominance behaviour and it is one of the things that can lead to fall-outs even in bonded adult pairs if there is an underlying dispute in the relationship.

You can minimise this problem by using bedding, which you have lined the carrier with in which you have brought your new boars home to make the new cage smell like their territory. Letting your piggies have a romp in the fresh bedding and scent marking it will also help them with the move into a place that shouts 'This is ours'.
Additionally wipe down all the new housing and cage with the scent marked bedding or at least a soft rag carrying their mingled scent. Guinea pigs have a much stronger sense of smell than we humans; respecting that important aspect can help to avoid bigger problems.

Guinea pigs go where others have gone before. I have only half height grids dividing the piggy room from our lounge, but I don't have piggies in my lounge because it is a 'no go' area that hasn't got any scent spoors. It really makes a difference to introduce any new areas as a 'here be cavies' zone!
The same goes for any cage extension, exercise run or new area you want to introduce. It can also help with those teenage boars that get upset each time you clean their cage and remove all their territorial scent markers!

If your moved or newly arrived adult boars get into trouble despite your efforts, you will find the tips in this guide here helpful: Bonds In Trouble

Exercise indoors and outdoors runs - emergency housing
Puppy or rabbit indoors or outdoors runs give your guinea pigs extra interest and stimulation to run, popcorn and explore; this is especially important when you haven't got much cage space. The foldable puppy runs or metal panel rabbit runs can also double up as a second cage in emergencies. I use them also for bonding and re-bonding purposes.
Please make sure that you use a plastic sheet layer underneath your fleece and underlay liner, especially when you live in rented accommodation or use your extra as an emergency hold for temporary separations etc.
Temporary Housing Solutions?

When you introduce the run once your boys have settled in and are confident in their regular cage, use some used fleece as a ground cover for the first time and dot hideys, tunnels and cardboard huts around about 1 ft apart from the next one to give your boys a feeling of 'this is safe territory' and points from which to explore the next new stretch.

Please do NOT free roam your guinea pigs outdoors without supervision and once you have made sure, inch by inch that you haven't got any areas that are not safe or where your guinea pigs can wiggle out through a surprisingly small gap between a fence and the ground, especially not new ones that can take fright, run off and get lost or predated. You best also train your guinea pigs to come to you for a treat or pick up reliably before you try anything like that! NEVER let your children do this unsupervised!
Always use a safe run with a dog/fox/cat/birth of prey safe cover and never leave your guinea pigs exposed to the sun with only a plastic hut to have a heat stroke in!

Boars and sows in the same room
The rule of thumb is:
- If at all possible, avoid introducing sows into a boars-only room!
Sow should be well out of sight and reach of boar pheromones at all times. Introducing sow pheromones for the first time will always cause a much greater reaction.

- If you can't do that, keep them preferably as much away as possible, on a lower level than boars or if you have to have the cages next to each other, with an opaque divider that is higher and wider than the cage in order to prevent sow pheromones getting to the boars and cause fights/fall-outs when they come into season.

If your boars have grown up in the presence of sows and alwaysd have been around sows, they are much less reactive to sow pheromones and the hubbub that a strong season can cause.
However, especially teenagers can react to a strong season or a lively mixed gender introduction. The ensuing strong cloud of pheromones can cause some scuffles or even a fall-out in a pair that is already under strain.

If possible keep the boars above the sows and if necessary keep dodgy teenagers as much out of reach of sow pheromones as possible.
Adult and laid-back boar pairs used to sow presence can live next to sows, but that is very much up to your judgement. It can go wrong all of a sudden!

- You can at all times place a single boar next to sows or a mixed gender pair/group as long as there is no chance of him escaping.
A traditional cage is STRONGLY recommended and here is why.

Any C&C grids need to be additionally cable-tied and capped with something firm at the top. Midwestern grids can be jumped.
This video shows you how well a determined guinea pig can climb: Who says guinea pigs can't climb?
(with permission of Cavy Central Guinea Pig Rescue)

Any inevitable chewing and rattling should mostly die down within 2-3 days but it will pick up again when a sow is coming into season.

- But you CANNOT place a sow next to your boar pair if they are not used to sows and should not be placed in full sight/pheromone reach of any teenage boars anyway while their bond is already under major stress from sudden strong testosterone spikes.

- Neutered boars react to sow pheromones no less than full boars as they are an important part of communication and exchange of biological/health/status information. Please keep in mind that guinea pigs have a much stronger sense of smell than humans!
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IV Companionship

Pairs, trios or quartets?

Boars are best kept in pairs!

If you want more boars, please don’t rock the boat and add another; rather look for another separate pair!

Most baby boar trios end with at least one separation or at the worst three single boars before they reach adulthood.

Nearly all quartets will fail before they reach adulthood.
The fail rate in boar trios and quartets is always much higher than the success rate, but same age teenage boy trios and quartets have an extremely high fall-out rate. In either case you can end up with all singles that won’t go back with each other if you are unlucky.
Sadly pet shops and for sale breeders are still happily selling what the customers asks for and not what is actually for the benefit of the species they selling!

It is tricky enough to balance out two evolving boar personalities when they go through the same teenage spikes together, but balancing out three or four testosterone driven boars is near impossible in traditional cage setups. Our behaviour section is sadly littered with threads by desperate owners of fighting or fallen-out boar trios or quartets who have been happily sold any number of babies by pet shops or breeders.

Trios can work if all boars are on the laid-back side and if they can choose each other. Adding a third boar, even a baby, to a bonded pair on spec can however be easily a recipe for disaster. We have seen a number of cases where this has led to a fall-out or fight between the bonded pair.

The only successful boar quartets I know of have either got a disabled/carer companion combo with very different interactive dynamics, oodles of space to allow each boar his own territory or they are old pensioner groups where the testosterone has long fizzled out and the need for companionship outweighs any previous status struggles.

Boars can work again in larger bachelor groups if they share an area of at least half or all of a sizeable room or outbuilding. In this case, space to get away is key again as well. There is also a group instinct, which is absent in trios or quartets, that will kick in if boars perceive themselves as a herd. You still have to factor in a hospital and separation area for possibile confrontations.

How to best go about getting a stable boar pair?
Hand on your heart, how many of you would think of spending a good deal of time watching babies on the shop floor with a view to which two are hanging out with each other all the time rather than falling for cute looks? Yet it is the friendship which is so much more important for the success of a boar bond than the individual looks!

Of course there is a much safer way of getting boars than staring at shop babies if you can get there: Adoption from a good standard rescue with mandatory quarantine and vet care that takes care when pairing up their boars and testing for a stable bond and that also makes sure that any guinea pigs leaving the rescue are properly sexed. These rescues will also support you throughout the settling-in period and the whole life of their adopted guinea pigs if you run into a major problem.
Please be aware that anybody can call themselves a rescue without licensing and any supervision, and the results can be accordingly.
The links to rescue lists below only feature vetted rescues of good standard and practice at any stage for several that we can vouch that you are in safe and experienced hands.

Adoption also offers you a neat way of avoiding the teenage months altogether: Adopting stably bonded adult boars that are already used to handling and a home environment!
Guinea pigs are cute babies for just a few weeks, teenagers for months but they are adult for years, so you still have plenty of time to enjoy your boys.
There are so many no longer wanted boars in rescue where children and families have lost interest, have health issues or were unable to find a new home that accepts pets. These boys are usually used to being handled and in a home environment, so unlike with shop cavies that haven’t had anything in the way of human contact or home life, you can get started straight away.
Any good rescue will give you their recommendations as to which of their guinea pigs ready for adoption are most suitable for the home they are going to – and that is more important than looks.

Older boars are something for those that love snuggle companions to share their sofa with. Don’t be fazed by the age: the enjoyment you’ll get transcends time! Some of my most wonderful guinea pigs have been oldies, and I would not miss any of them. Healthy older guinea pigs may also surprise you with how long they live with their reinvigorated joy of life and your loving care…

If you cannot access a rescue but want to get second-hand guinea pigs, you should be aware that all the risks are on your side.
People keen on getting rid of no longer wanted guinea pigs have a habit of not telling you some crucial information about existing health problems or whether the boars really get on – or they may not even turn out to boars or both boars…
It is not to be recommended if you cannot afford vet care or a divided cage since it can turn into a very steep, expensive and taxing learning curve as several well-meaning forum members have found out the hard way!

There is also a growing number of rescues that offers dating any bereaved or single boars of yours with suitable ‘bachelor’ rescue boars or in a few cases, spayed sows (there are a very few US guinea pig rescues with a spaying policy and Auckland Cavy Care rescue in New Zealand, but no UK or Australian rescues).

Links to recommended good standard rescues in several countries:
UK: Recommended Guinea Pig Rescues
Several other countries: Guinea Lynx :: Rescue Organizations

Introducing boars at home
If you want to introduce boars at home, it is abolutely vital that you have a plan B in case of failure
as you have a roughly 50:50 chance of the bonding working out. Long-term experience with rescue boar dating shows that it takes on average about 1-3 introductions to find ‘Mr Right’; teenage boars in the thick of it may take even longer.

Acceptance of baby boars is generally higher, but not perfect. However, you then face the risk of fall-outs during the teenage months when the baby is developing his adult boar identity.

Boar dating needs to be done in one go and cannot be interrupted!
The major difference when dating boars with other boars is that you can’t bond them in a series of short meetings and in stages.
If you are not sure, you can leave the boars overnight in the bonding area, but you cannot separate halfway through or at the first sign of dominance behaviour. After each separation the boars have to start the bonding process right back in square one. How can you bond properly through the complex bonding process if you are not allowed to say more than ‘hello’ to each other? The more you interfere, the less chance you give your boys to bond.
As hard as it is (and it can be extremely taxing), please sit by and only separate if your boys get into a proper fight with heir hackles up or if truly incessant mounting over hours is causing the other boar to not be able to eat, drink or sleep unmolested.

The good thing about boar bonding is that boys are generally upfront and that you know usually fairly quickly in which direction things are heading. Rumble-strutting, mutual mounting and chasing are part of normal boar bonding.
A bond stands and falls whether the boys tolerate this from their future mate or not. Some boars can go overboard and go into a humping frenzy, mounting the other party in whichever way (you can also experience that with cross gender dating from a neutered boar).
Please make sure that the humping is not so bad that the other party can’t eat, drink or sleep or feels absolutely harassed that is crosses the line into bullying. Not every piggy can stand up for themselves. It is useful to provide a piggy sized stuffed humping toddler safe humping toy to draw some of the fire when boar dating as well as a safe refuge (with two opposite openings) that a larger boar cannot get into when bonding a baby.

You have to also accept that there is no magic trick in the book (and we have tried them all over the years!) that can make your boys go together if they decide that they don't suit - you simply cannot change their personality.
This includes the much touted bonding baths, which actually only delay the bonding ritual but do not contribute constructively to the ultimate outcome. In the end it always comes down to whether your boars want to live together or not.

Before you start bonding I would strongly recommend you to please read our comprehensive illustrated bonding guide, which covers the whole process stage by stage from the preparation to the end of the post-bonding dominance phase some weeks later. It also contains special chapters on special aspects of boar, baby and mixed gender bonding.
Bonding and Interaction: Illustrated social behaviours and bonding dynamics


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V Neutered boars

Contrary to what vets with little or no experience with guinea pigs recommend, neutering does NOT curb aggression, change personality nor does it change social interaction and dominance behaviour.
All it does is to take away the ability to make babies.

In short, neutering won’t calm down clashing boars!

It is especially not an instant testosterone killer as neutered boars can still produce an amazing amount of testosterone-laden pee when they get excited!
Neutered boars still rumble-strut and mount (which are dominance behaviours used by both sexes), and they measure up against each other just the same as full boars. They also exhibit all the normal behaviours when in the presence of sows.

Neutering your boars makes sense if you struggle with access to boar dating rescues but have access to a good neutering vet or are planning to bond your fallen-out boars with a sow each after a 6 weeks post-op safety wait because cross gender bonds are the most stable of all piggy bonds.

Adult boars can be successfully neutered up to 4-5 years old.

You CANNOT keep two neutered boars in the same group with any number of sows!
It is a sure-fire recipe for fights in a normal cage set-up.

Also be aware that acceptance of neutered boars by any sows is the critical point with cross gender bonding.

By far not all sows will accept all boars; especially not all adult sows. And in the guinea pig world, it is the sows that call the shots when it comes to who they want to associate and mate with. A boar can successfully mount a sow only if the lets him, whether that is dominance mounting or sexual mounting when she is in season!

Mutual liking comes at all times before any age gap.
I currently have a 3 year old boar very happily living with a now 8 year old sow and a baby girl that has joined them at 5 weeks old; they have been together for over half a year now. The young girl has given my old sow a renewed zest for life. This is of course an extreme example, but it may serve as an illustration for not thinking in to narrow a box when looking for love!
The boar was 5 months old when he and a 5 year old sow (the sister of my old lady) fell head over heels for each other and they stayed that way for over two very happy years until the sow’s death aged 7 years.

A ‘husboar’, i.e. a neutered boar living with one or any number of sows, is a very happy boar indeed since he has achieved the pinnacle of any boar’s ambitions.
There is nothing comparable to witnessing the moment of total bliss when a neutered boar realises that there is a boar Heaven on Earth – and it is HIS for the taking!

If you have boars and sows living in the same room on the same level, you may want to consider having your boars neutered if you have access to a good vet and the operation is not too costly. It ensures that there can't be any pregnancies from accidental or misguided mixing and you have the option to re-bond a bereaved boar with your sows. It makes finding new companionship especially for an older boar much easier because you have more options.

You can access our comprehensive information on neutered boars and neutering operations (including post-op safety wait information and post-op complications list) via this link here: Neutered / De-sexed Boars And Neutering Operations: Myths And Facts


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VI Health problems and boar care

Please always have a quick check of your boar bits and grease gland during the regular life-long weekly weigh-in and body onceover in order to catch developing problems early on.

What to look out for:

- Any unusual swellings in the groin area need to be vet checked.
Please note that descending testicles appear initially as swellings to both sides of the genitals around 3-4 months.
But lumps can also be caused by abscesses or infections in the whole genital area or some other rare problems as a late neutering complication (full list of possible issues in the neutering guide link in the previous chapter).

- Swollen genitalia in older boars or boars with problems in the lower body can be an indication of impaction; this affects about 10% of all boars. Neutered boars can also be affected by but as they don't have the large anal sac cavity created by fully descended testicles, they don't suffer quite the same extent of built-up caecotrophs (redigested poos) as full boars.
Please have any boar you suspect has impaction checked by a vet in case it has started an infection and needs medication. Do not diagnose on spec as you can easily overlook a less known problem and lose your boy to that.

- Check and clean the anal sac in full boars every 1-2 weeks, depending on how messy your boys are. All guinea pigs scent mark with a gland situated just in front of the genitalia, but some boars are better at picking up all kinds of stuff in their anal sac when they wipe it over the floor!

- Check the penis every 2-4 weeks for a build-up of smegma and painful rods (hardened semen in the penis shaft). In very active teenage boys you may want to do this weekly.
- Always check the penis for a good colour. If the penis is bluish in colour, it has likely got a hair strangling it and will have to be seen by a vet ASAP. The same goes if the penis shaft is extended and very swollen - again, this counts as an emergency.

- Check the grease gland weekly. It is located about a finger’s width on the back above the genitalia; you can find pictures that show it clearly as well as cleaning tips in the boar care guide.

- Excited full and neutered boars can also get white semen fluid on their companions; the hardened stuff is very aptly called ‘boar glue’ due to its difficulty of removing it. If it cannot be cut off gently from any hairs, you have to wait until it falls off on it own eventually as otherwise you can rip off the skin with it. Boar glue is most common during the teenage hormones spikes, but even adult and/or neutered boars can produce it. And yes, boars do masturbate and can end up with it on their lips and noses, not to mention smearing it all over their companions of either sex or on the bedding when scent marking.

You can find very helpful detailed and illustrated information on all the boar bits and their care in our very helpful boar care guide:
Boar Care: Bits, Bums & Baths

More information on boar specific health problems can be found in these links here:
Impaction - How To Help Your Guinea Pig.
Warning To Vet Check Irregular Boar Bits

Our advice for the life-long weekly health and weight monitoring:
Weight - Monitoring and Management
Guinea pig body quirks - What is normal and what not?

VII Conclusion

If you respect boars for what they are, plan around with providing space and aim for mutual liking and matched personalities, you will indeed reap rich rewards! With some careful measures, you can up you baby boys' success chances a lot, even if your boars are not personality matched.
It is worth repeating that the majority of all boar pairs won't fall out!

Starting with already stably and carefully bonded boars is however always much easier. If you are worried about teenage fall-outs, why not adopt a pair of post-teenage adult boars that are already used to a home environment?
Or, if you can’t make up your mind about sows or boars, then a mixed gender pair where one side is de-sexed is the way forward for you!

It is a sad reality that most guinea pigs ending up in rescue are boars because they have been failed by shops, breeders, and their owners (or most likely their children have soon lost interest or given up on them once they stop being cute babies and turn into scrapping teenagers. Bonded adult boars make great pets! But so do 'hopeless' or 'unbondable' boars that have been neutered and that can live the happiest of boar lives as 'husboars' in the company of sows - I have and have had a succession of them; a good number of them boars that would have otherwise be consigned to a single life.

Boars are best kept in pairs. If you are looking for three guinea pigs specifically, consider a neutered boar and two sow combo instead of three boars or the rare stably bonded boar trio; ideally from a good rescue to ensure that they really get on and that you have a fall-back if that is not the case.

Whether it is finding a partner for your single or bereaved boar or extending a mixed gender group, try to let your guinea pigs make the decision who they want to live with. Guinea pigs are very much tiny people in fur coats, and they have very much their own ideas as to who they want to get on with. You will reap the ample rewards by going the extra mile!

I sincerely hope that you will consider giving boars a chance - if you go into it with open eyes and good preparation, then there is nothing that says that you cannot enjoy your boys.

PS: Before you make a dash for sows, better read these two guides:
Boars, sows or mixed pairs; babies or adults?
Sows: Behaviour and female health problems (including ovarian cysts)

And read our Wannabe Owners' guide collection so you can make as informed a decision whether guinea pigs are indeed the right pets for you for the next 5-7 years: Getting Started - New Owners' Most Helpful Guides
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