Sexing Guinea Pigs | RSPCA - RSPCA
Avoid unwanted litters
Guinea pigs are sociable creatures and don't like to live alone. So caring owners will keep two, or more, together. You may believe you're buying animals of the same sex - happy that you're avoiding unwanted litters - but this can be wishful thinking.
If your guinea pigs include an unneutered male and female, you'll soon end up with babies (pups). And the number of pups can multiply quickly - pregnancies last around 9 to 10 weeks and then the pups can get pregnant when they're only two months old or sometimes even younger. Meanwhile, the mothers can get pregnant again within hours of giving birth.
Use our guide
Don't just rely on your breeder or pet shop. It's much safer to check the sex of your guinea pigs yourself. Perhaps you're first-time guinea pig owners, or you've just got a pair of new guinea pigs.
To help you tell male and female guinea pigs apart, we've put together a handy illustrated guide:
How to hold your guinea pigs
Be firm and gentle when handling your guinea pigs - and stay quiet and calm.
If they're not used to being handled, this could be stressful for them and they may struggle and try to escape. If so, try again when they're calmer. If they remain stressed, please ask your vet to check the sex for you instead.
When you're trying to sex guinea pigs, it can be easier to sit with them on your lap or on a table, as they can wriggle. Put a towel on the table first to make it less slippery. Don't hold them on their back as they find this very stressful.
It will be difficult to hold your guinea pig and sex them simultaneously, so it's best to ask someone to help you.
- To handle your guinea pig, keep them secure by placing one hand across their chest.
- Hold them upright and close to your body.
- Place one hand under their bottom. This will support their weight fully. You should now be in a position to identify the sex.
How to tell if your guinea pig is male
A male guinea pig's genitals look like a lowercase letter i. This is the case whether they have been neutered or not. Follow the step below to confirm that your guinea pig is male.
Unneutered
- Apply gentle pressure above the guinea pig's genitals
- If the guinea pig is male and hasn't been neutered, the penis will emerge and the testes will be obvious.
- The anus sits at the lowest point below the unneutered male genitals and is separate from the genitals.
Neutered
- Apply gentle pressure above the guinea pig's genitals.
- If the guinea pig is male and has been neutered, the penis will emerge but you won't be able to see any testes.
- The anus sits at the lowest point below the neutered male genitals and is separate from the genitals.
How to tell if your guinea pig is female
A female guinea pig's genitals look like an upper case letter Y. Follow the step below to confirm that your guinea pig is female.
- Apply gentle pressure above the guinea pig's genitals.
- If the guinea pig is female, nothing will emerge - you will just be able to see her vulva.
- The anus sits at the lowest point below the female genitals and is separate from the genitals.
Don't forget to check the sex of any offspring
If your guinea pigs do have babies, it's important to check each young animal to find out which sex they are. Then you can keep the girls and boys apart and make sure you don't have more surprises!
If in doubt, ask your vet
If you're still not sure whether your guinea pigs are male or female, or if you want advice on how to handle them, please talk to your vet.
Neutering
Male guinea pigs should be neutered unless you want to breed from them and have plans in place to care for parents and babies.
