Can Guinea Pigs Change Genders? | All You Need to Know

As much as absurd it sounds, many guinea pig owners talk about guinea pigs changing their genders.

So, can guinea pigs change genders? Guinea pigs can’t change genders and are born either male or female. However, during their younger days, guinea pigs are sometimes hard to distinguish as their genitalia aren’t developed to a certain degree.

That being said, we’ll cover more about guinea pig genders, as well as how to distinguish male from female ones.

How Can Guinea Pigs Change Sex?

Guinea pigs simply don’t change sex. However, it is possible for male guinea pigs to retract their testicles, making them look like the female guinea pigs. This is especially strange and requires constant attention, to avoid making a mistake. But, it’s not only common for guinea pigs, but also for other animals to retract their testicles inside the abdomen.

Since young guinea pigs have fairly small testicles, it’s even harder to safely tell if that guinea pig is male or female. Nevertheless, you’ll be able to determine the gender only if you pay special attention to their behavior.

How to Determine Guinea Pig’s Gender?

How to Determine Guinea Pig’s Gender

First, you’ll need to use your hands as they can’t be determined only by looks. When it comes to female guinea pigs, they have a bit flatter look with a well-developed ‘Y’ shape. If you touch the genitalia area with your hand, you won’t be able to feel any kind of protruding. On the other hand, male guinea pigs are a bit easier to distinguish. They have a line with a penis that can be seen and it’s in the shape of a line.

When touching the genitalia area, you’ll be able to feel the protruding. And if your guinea pig is a bit older, this touch will also greatly protrude the penis, which is proof that you have a male guinea pig. Still, if you aren’t 100% sure, it’s best to take them to a veterinarian and let this professional determine the gender.

When Do Guinea Pigs Become Fertile?

When Do Guinea Pigs Become Fertile

Before we delve deeper into this subject, it’s important to mention one thing. By breeding a guinea pig, its lifespan is being reduced, and this only applies to female guinea pigs. When it comes to breeding them, unfortunately, you have very little time to do that.

Although female guinea pigs become fertile after 4-10 weeks of age, it’s not recommended to breed them immediately after that period. The recommended time to start is about four months of age. During this time, they aren’t yet in their adulthood, meaning that it’s the perfect time to start breeding. But, an important thing to remember is that you do your breeding before eight months of age.

Breeding a female guinea pig at eight months of age or more is sometimes going to decrease its lifespan drastically. And after eight months, a female guinea pig is slowly reaching adulthood. This means that it sometimes can’t deliver offspring successfully. In this case, a veterinarian with a fair amount of experience should help your guinea pig bring the babies.

As for the male guinea pigs, breeding can be done a month earlier – at three months of age. While the male guinea pig can mate at any time of the year, female guinea pigs often have an estrous cycle in the spring. The length of this cycle is usually about 16 days, and the new estrous cycle begins right after giving birth.

Neutering a Guinea Pig

If you don’t want your guinea pig to give birth, neutering can be done. But, neutering a small animal is a complex process, especially when we talk about surgery. It does carry some risks with it, and it’s much harder to spay a female than a male guinea pig.

On top of that, guinea pigs are small animals. Small animals usually don’t react well to anesthesia or surgery in general. The safest way to keep them from mating is to keep your male and your female guinea pigs in a different cage.

On the other side, if you strongly decide to neuter your guinea pig, make sure to choose a veterinarian with lots of experience in this subject. After the surgery has been done, it’s important to let them recover in a quiet place, separated from the other pigs. Of course, during the recovery time, you should give it plenty of quality food and Vitamin C.

Can Guinea Pigs Be Hermaphrodites?

Guinea pigs cannot be exactly hermaphrodites. Although they can retract their testicles, this doesn’t make them hermaphrodites or female guinea pigs. Unlike some animals which can be hermaphrodites, guinea pigs are either male or female. A classic example of an animal being hermaphrodite is a snail.

Most snails are hermaphrodites which can easily be proved by putting one snail in an empty tank. Even if there aren’t other snails, you’ll see an increased number of them each day.

But, not every type of snail is hermaphrodite. Some snails do require a combination of male and female to produce offspring, but a vast majority of them are true hermaphrodites. And when it comes to changing genders, there isn’t a mammal on this planet that can do that.

Some say that fish and crustacean species have these abilities, but even then, changing gender is very rare. With Guinea pigs, not only that this doesn’t happen, but it’s completely impossible. So, if you worry about your male Guinea pig turning into a female, that just isn’t going to happen.

Do You Want to Breed Guinea Pigs?

Do You Want to Breed Guinea Pigs

If your answer is positive, you should get either female or simply both. And if you want to have only one guinea pig, you can go with either choice, but neutering is sometimes obligatory.

As we mentioned before, neutering a male guinea pig is much easier than neutering a female one. So, if you plan to do this, you should opt for a male one. It’s also important if you already have a guinea pig or a couple of them. If you have a few males, it’s better to buy a male and not a female.

The reason for this is that all of these male guinea pigs will want to mate, and a single female won’t be able to always keep them off her. And if you plan on buying a male guinea pig, introducing it to your older males is crucial, as fights can occur.

Should You Buy a Male or a Female Guinea Pig?

Should You Buy a Male or a Female Guinea Pig

You can decide to buy male or female guinea pigs depending on the following factors:

Based on Their Personality

Male Guinea Pigs:

Male guinea pigs are popular because they form instant connections with their owners. They are more extroverted, self-assured, and welcoming. The male is considerably more ready to let others hold them or sit on their owner’s lap. But if given the chance, it will also run out and explore. 

The male guinea pig may be simpler to handle if you’ve never owned one before. However, if there are too many males in a tiny cage, they may get territorial and fight. So, you have to make sure they have adequate room.

Female Guinea Pigs:

Female guinea pigs are more reserved than males. They are easily startled, which causes them to flee. A new owner who doesn’t understand why the guinea pig is anxious might be frustrated by these pets. They are also less likely to let you carry them. But with time and care, your female guinea pig will attach to you and become almost as sociable as the male. 

Once they’ve been acquainted with you, they’ll prefer to be near you when they’re terrified. They’ll also assist and comfort any other fearful guinea pigs you have.

Based on How They Should Be Cared For

Male Guinea Pigs:

Male guinea pigs are significantly messier than female guinea pigs. They will scatter their bedding, food, hay, etc. in the cage, potentially causing it to fall to the floor. Regardless of their untidiness, they’ll need a steady supply of timothy hay, fruits, and vegetables to eat and wear down their continually growing teeth.

Men and female guinea pigs appear to be identical, but men might be up to one-third heavier. This means that they need more food and activity to avoid getting overweight. They also have a scent gland to mark their territory, which might give an odor that some people don’t like. However, you can simply get rid of it by bathing more frequently.

Female Guinea Pigs:

The female guinea pig, like the male, will need an endless supply of timothy hay as well as lots of fruits and vegetables. They are considerably cleaner and are less likely to mess up their environment.  

Many individuals prefer females because they are cleaner and require less maintenance than male ones. Both the male and female guinea pigs will need their nails clipped and a wash every now and then.

Based on the Suitability for Owners

Male Guinea Pigs:

Male guinea pigs are a good choice for first-time guinea pig owners. They’re a little more outgoing and brave, so they won’t hide for the first time you have them. Their filthy temperament may take some time to get used to, but it will provide you with the necessary experience to care for these creatures.

Female Guinea Pigs:

Females are a better option for individuals with adequate experience in caring for a guinea pig. These owners know that they should give her time to adjust to her new surroundings before pressuring her to make friends. If you wish to have numerous guinea pigs, females are also a wonderful choice since they will not only soothe them but may also avoid or reduce the possibility of territorial disputes between males.


Guinea pigs can’t change their gender. Since male guinea pigs can retract their testicles, it’s often mistaken that they can magically change gender, although it’s the opposite. A male guinea pig will be born as a male and die as a male, regardless of this strange ability. As for the female guinea pigs, they also can’t change their gender, and breeding is best in the period of 4 to 8 months.

Before you get a guinea pig, you should always carefully choose between male and female. If you want only one guinea pig, it’s best to buy a male one. However, it’s quite hard to have only one, as they are so adorable.

List of Sources

Care of Guinea Pigs

Caring for Your Pet Guinea Pig