Sexing Guinea Pigs

Sexing guinea pigs is critical, whether you’re looking to adopt a grown pair or just had a litter of pups. While the process can be a little intimidating to start with, once you get the hang of it, it goes quickly.

Remember, if you have trouble sexing your guinea pig, your guinea pig gets too stressed, or you simply don’t want to do it yourself, a licensed veterinary professional can reliably sex your guinea pig.

Why Bother Sexing Guinea Pigs?

Guinea pigs are rodents and can get pregnant easily in their fertile windows. If a female guinea pig lives with a male, she may fall pregnant. Worse, if she’s living with siblings, she may fall pregnant by one of her brothers.

Obviously, unintended litters are a strong negative. Sexing guinea pigs lets you separate your guinea pigs and understand what to expect from each guinea pig involved. It also limits your potential problems down the road.

Trio of young guinea pigs

What are the Key Differences Between Guinea Pig Sexes?

Male guinea pigs (officially called “boars”) tend to be a little bigger, a little bolder, and more than a little territorial. As a result, there is a greater chance a male guinea pig will need his own cage and that he may need treatment for impaction (though the chances of needing this treatment are small).

On the other hand, female guinea pigs (officially called “sows”) tend to be a little smaller, a little more timid, and a lot more tolerant of social groupings. A female guinea pig may also be less confident and more likely to develop a UTI.

How to Handle Sexing Guinea Pigs

Sexing guinea pigs is a process, but it should only take a few minutes. Professional veterinarians can do this in under a minute if they are familiar with exotics.

Step 1: Hold the Guinea Pig

Before you begin sexing guinea pigs, you need to understand that this is not a comfortable process for the guinea pig. Even the best-socialized guinea pigs will squirm. For this reason, some people find it easiest to wrap the guinea pig in a towel to limit their movements.

You will need both hands to sex your guinea pigs; some people find it helpful if they have a second set of hands too. The goal is to position the guinea pig so that its back is against your belly for stability.

You will need to keep one hand under the guinea pig’s butt to support its weight and minimize the chances of them wiggling in that direction. The other hand usually goes under their front paws to hold them upright.

Guinea pig on books

Step 2: Press Just Above the Genitals

Now that you have the guinea pig in position it’s time to palpitate gently. You must be gentle while doing so, or you could hurt your guinea pig. Also, remember to press above the genitals, not on them.

If you’re doing this yourself, typically a finger from the hand holding near the guinea pig’s front legs is sufficient. If you have help, let them do the pressing and focus on keeping the guinea pig secure.

Step 3: Observe the Change

When you press gently, the upper part of the genitals should pop out. Unfortunately, this change can be difficult to see on some guinea pigs, especially pups who may be a little too young for the process.

If the guinea pig is male, you should see a round structure with a little bit of length. This protrusion will resemble the human male anatomy. There will also be scrotal sacks, though only if the male guinea pig is unneutered.

If the guinea pig is female, there will be a prominent “V” shape with only a little rise between the two edges of the “V.” Typically, the formation between the “V” is smooth and blends with the rest of the skin.

When Can You Sex Guinea Pigs?

You should sex any guinea pig you adopt or who is born in your care as soon as possible. For adult guinea pigs, you should do this before you leave the pet store or rescue. You do not want to come home to a surprise.

For pups born in your care, sexing them may need to wait until they are a week or two weeks old. Until that point, the genitals are very small, and you may have trouble distinguishing between the sexes. However, it’s vital to sex the guinea pigs and separate the males as soon as mom weans them, which is usually at the three- or four-week mark.

Remember, having a vet sex your guinea pigs is always a viable option, and you can ask your vet to show you.

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