How to identify guinea pig sex: Is it a boy or a girl?

We all love our furry friends, but do you know how to identify guinea pig sex? Mistakes can easily be made, and unplanned litters arrive. This article will help you to figure out whether you’ve got males or females and what to do if you end up having a male and a female.


Maybe you’ve bought your guinea pigs from a pet shop, online or from a friend. Or perhaps you chose to adopt one of the many guinea pigs looking for a forever home at a rescue centre. Either way, it is best to double check the sex of your guinea pig. But how are you supposed to know what you’re looking for?

Picture of a guinea pig
picture of a guinea pig

Here are two of my guinea pigs, but which one is male, and which is female? Read on to find out how to identify guinea pig sex.


Female guinea pigs are called sows. Dot is my example sow in this post. All guinea pigs have two teats like humans, so this cannot be used to determine sex. The main thing to look for when trying to identify their sex is a “y-shape” in the genital area.

how to identify female guinea pig


Male guinea pigs are called boars. Duke is my example boar in this post. When sexing male guinea pigs, you should be able to see a slit with a circle sitting above (this is the retracted penis). To extend the penis, press down gently above the retracted penis moving your finger in a small stroke down the body towards the anus.

identify male guinea pig sex

It is very important to know the sex of your guinea pig as they reproduce easily, and unplanned litters will arrive.

Males are usually the better of the two to be neutered as it is a less complicated procedure. Males can breed at around 1 month old. Therefore, you need to keep males and females separate at quite a young age. Females reach sexual maturity when they are around 10 weeks old.

If you check your guinea pigs and find that you have a male and a female, it is a good idea to separate them immediately. You’ll have to keep your guinea pigs in two separate enclosures to prevent them from breeding until you can get your male neutered. In the unfortunate event that you are unable to keep them separately and need to rehome them, please try to rehome them to a rescue centre who will find them good homes.

You will also need to keep an eye on your female as she may be pregnant. Guinea pigs are pregnant for 59-72 days and will need extra care during this time. A vet may be able to do an ultrasound or other tests to determine if your sow is pregnant.

Now you know how to determine guinea pig sex. Don’t just assume that your guinea pig has been sexed correctly. This is important so that you don’t end up with lots of unplanned babies.

Don't miss out! Sign up to receive our newsletter and stay up to date with your pet information!

2 thoughts on “How to identify guinea pig sex: Is it a boy or a girl?

    • surroundedbyanimals says:

      I’m glad you’ve found my post helpful. I’m sorry to hear about Bravo passing away, it can be very difficult to lose a pet.

Leave a Reply

Your email address will not be published. Required fields are marked *