Are you considering breeding from your pet guinea pig, and looking for some advice?  Here it is - please don’t.  There are any number of reasons for not intentionally breeding your guinea pig, most of which have to do with the fact that there are enough unwanted guinea pigs in the world, and that if you’re looking for guidance here, then you probably don’t have enough knowledge to avoid the many pitfalls.  Do you know which colours should never be mated together, as they will produce deformed babies?  Do you know why females over the age of seven or eight months should never be mated for the first time, and what could happen?  Do you know how to sex the babies, and at what age to separate the sexes?  Your piggie is your pet, why would you subject her to the risks of pregnancy?  To make money?  Do you know how many guinea pig pregnancies end in problems, and how much it would cost to have the vet treat her?

Some people say they want to breed their pet guinea pig (or cat, dog, etc) because they want their children to experience the miracle of life.  Perhaps they should also take them to the local animal shelter, so that they may witness the tragedy of death.  Hundreds of thousands of healthy, adoptable companion animals are killed in shelters every year, simply because homes cannot be found for them.  Do you really want to add to this tally of misery?

If you are still considering going ahead, please read this first


This is Gwyn.  He was born suffering from Lethal White Syndrome, a genetic condition which occurs when two pigs carrying the roan or dalmatian gene are mated together.  Lethals are born without pigmentation and are almost always blind and deaf, and suffer from malformation of the palate and jaw, leading to dental issues.  In addition, many have internal problems which prevent the efficient absorption of nutrients.  Some are stillborn, some die shortly after birth as they have a cleft palate which prevents them from suckling, and many die at weaning as their digestive system cannot handle the changeover to proper food.  Although we initially had high hopes that Gwyn was high functioning and would be able to live into adulthood, at four months of age he had to have a full dental because his mouth (described by our vet as a “genetic disaster area”) was so malformed that the teeth did not match up and, with nothing to grind against, overgrew to the extent that he could not close his mouth, causing him considerable pain and making it impossible for him to eat or drink.  He made a full recovery from the surgery but, just three weeks later, was back in the same situation again.  Faced with the certainty that his life would consist of frequent painful surgeries with very little time between recovery and the onset of further problems, we decided that his quality of life would be severely curtailed, and with great sadness had him put to sleep.


Unfortunately, many people who buy guinea pigs from pet stores find themselves in this predicament, as either the guinea pigs are mis-sexed and the pair of females turns out to be one of each gender, or the pigs are already pregnant when they get them.  A baby pig as young as just four or five weeks old could possibly be pregnant, and this may not come to light for some while, as guinea pigs are pregnant for 10+ weeks.  Please read the following carefully, to be sure that a problem doesn’t turn into a disaster, as it doesn’t take long for an unexpected pregnancy or a mis-sexed pair to turn into a population explosion.

Feed mom a good quality diet - plenty of pellets (alfalfa-based, formulated for guinea pigs), fresh veggies/fruit and hay.  Minimize handling as she gets larger, as her internal organs are already being compressed by the growing babies.  If you need to pick her up, scoop her up with both hands and make sure she’s fully supported underneath.

If the pigs are different sexes, make very sure that dad is not in the cage when the babies are born.  Female pigs come into heat big time within just an hour or so of giving birth and, if dad is still around, he will mate with her and she will be pregnant again.  This is to be avoided at all costs, as back-to-back pregnancies are particularly dangerous for guinea pigs.

Guinea pig moms can generally cope with giving birth quite well on their own (in fact, chances are the babies will be born when you’re not around), but if things go wrong, they need help very quickly.  If you witness any of the signs listed below, get the sow to a cavy knowledgeable vet immediately.

  1.     Straining for more than 10 minutes without producing a baby

  2.     Bleeding

  3.     Squealing loudly with each contraction

  4.     Getting exhausted and just giving up

  5.     No placenta being produced with the babies

  6.     Sow smelling like acetone (like the smell of nail polish remover) any time from 2 weeks

     before to 2 weeks after the birth.

You may be surprised by how the baby guinea pigs look when they’re born.  They are highly developed, and come out looking just like little replica adults - eyes and ears open, fully furred, ready to run.  Within just a few minutes of the birth, they will be up and moving around, albeit a little wobbly, and after just a day or two, you will see them starting to sample mom’s food.  They will still feed from mom for a couple of weeks, but will eat increasingly larger amounts of “real” food, so make sure you put lots of pellets (alfalfa pellets, formulated for young guinea pigs), veggies and hay in the cage every day.  The more variety of veggies you offer at this time, the better they will eat as adults.

You can handle the babies almost immediately after birth.  Mom will not mind this.  Handling them every day is a good thing to do, as it socializes them from an early age.  Obviously they are very small and delicate, though, so it is better not to allow younger children to interact with them, other than under very strict supervision.

Weigh each baby soon after birth, and every day for the first couple of weeks.  Record the weights and monitor closely to make sure every baby is thriving - increasing weight is the best indicator of this (a slight weight drop over the first couple of days is to be expected, but after that they should go up steadily).  If one baby is particularly small, or if you notice one not doing as well as the others, give him/her special time alone with mom, so that he/she gets a fair share of mom’s milk.

If you see any babies that are all white, with small or even missing eyes, crooked teeth or appear to be blind and/or deaf, contact us straight away for advice, as they may have a condition know as Lethal White Syndrome.  Lethals are always all-white, but not all white pigs are lethals.  Lethals can have a range of other disorders which may not be immediately apparent, so please do seek help.  See the information about Gwyn (above) for more details.

Guinea pig babies are weaned at around two weeks, and the males and females must be separated at about three weeks.  Guinea pigs of both genders can be reproductively mature as young as 24 days (yes, really!), so do not delay in doing this.  The baby girls can be left with mom, and the boys can be placed in the same cage as dad, if you have him - adult male guinea pigs make great parents - or otherwise they can be in a cage on their own.  If you do not know how to sex them, there are good tips here, or you can take them to a competent exotics vet who should be able to do it for you. 

When finding new homes for the babies, do make sure to ask for an adoption fee of at least $10 each and to ask lots of questions before letting anyone take them.  You are responsible for them, and it is your duty to set them up for a good life in a suitable home, where their needs will be understood and met.  See our Rehoming page for tips and suggestions.  Please do adopt them out in pairs (same sex, of course), and if there is an odd number, then try to make sure that the single piggie goes to someone who already has a pig of the same gender. 

If the pregnancy resulted from a pair of pigs having been mis-sexed, you need to decide what to do about dad.  Options are to get him neutered, to keep the pair in separate cages, or to rehome him with a male baby.  If you rehome him on his own, you are condemning him to a life of loneliness.

If you need any further advice or help, please do not hesitate to contact us at