How To Tell If A Guinea Pig Is A Male Or Female

**How to Tell If a Guinea Pig Is a Male or Female**

If you have recently adopted a guinea pig or are thinking about getting one, it’s important to determine the sex of your new furry friend. This will not only help you choose the right name, but also allow you to provide appropriate care and prevent unwanted pregnancies. So, how can you tell if a guinea pig is a male or female? Let’s find out!

Physical Differences

The most obvious way to determine the sex of a guinea pig is by looking at their physical characteristics. Male and female guinea pigs have some distinct differences that can help you determine their sex.


Male guinea pigs, also known as boars, have a few notable physical attributes. Here’s what to look for:

1. **Genitalia:** One of the most obvious signs is the presence of external genitalia. Males have a small penis-shaped projection called a penis sheath, which is located just below the anus. It’s usually more prominent in adult males.

2. **Anal Opening:** Another clue is the distance between the anus and the genitalia. In males, the anus is located further away from the penis sheath compared to females. This gap is referred to as the anogenital distance.

3. **Scent Glands:** Male guinea pigs also have scent glands on their belly. These glands produce a strong odor that is used for marking territory and attracting mates.


Female guinea pigs, also known as sows, have a different set of physical characteristics. Here’s what to look for:

1. **Genitalia:** Unlike males, female guinea pigs have a small vaginal opening located just below the anus. It has a slit-like appearance and is often referred to as the vulva. However, it can be challenging to see this distinction in very young or obese females.

2. **Anogenital Distance:** In females, the anus is closer to the vaginal opening compared to males. The distance between the anus and the vulva is usually shorter in females.

3. **Nipple Development:** Female guinea pigs have two pairs of mammary glands, which can become more pronounced and visible when they are pregnant or nursing.

Behavioral Differences

Apart from physical characteristics, guinea pigs also exhibit certain behavioral differences based on their sex. Understanding their behavior can further help you identify whether your guinea pig is a male or female.


Male guinea pigs tend to display some distinct behaviors that can indicate their sex:

1. **Mounting:** Male guinea pigs may try to mount other guinea pigs, regardless of their sex. This is a dominance behavior and is more commonly observed in males.

2. **Chasing:** Boars may engage in chasing behavior, especially when they are trying to establish dominance or when interacting with potential mates.

3. **Territory Marking:** Male guinea pigs have a tendency to mark their territory using scent glands. They may rub their scent glands on objects or perform a “rumble strut” to assert dominance.


Female guinea pigs tend to display different behaviors compared to males:

1. **Motherly Behavior:** Sows may exhibit motherly behavior, even if they haven’t given birth. They may build nests, gather food, and show grooming behaviors towards other guinea pigs.

2. **Vocalizations:** Female guinea pigs often make different vocalizations to communicate with others. They may purr, whistle, or make high-pitched sounds to express their emotions or attract males.

3. **Squeaking:** Female guinea pigs may emit a high-pitched squeak when they are in pain or discomfort. This can include during mating attempts or if they are being handled too roughly.

Frequently Asked Questions

Q: Can you determine the sex of a guinea pig by its size?

A: No, the size of a guinea pig does not determine its sex. It’s important to rely on physical characteristics and behaviors to determine whether your guinea pig is a male or female.

Q: How young can you tell the sex of a guinea pig?

A: You can usually determine the sex of a guinea pig from the age of 2 to 4 weeks. At this age, the genitals start to develop, making it easier to differentiate between males and females.

Q: Can guinea pigs change sex?

A: No, guinea pigs cannot change their sex. Once their sex characteristics have developed, they remain the same throughout their lives.

Q: Is it possible for a guinea pig to be hermaphrodite?

A: While extremely rare, there have been a few reported cases of guinea pigs being hermaphrodites. These individuals possess both male and female reproductive organs.

Final Thoughts

Determining the sex of a guinea pig is essential for their proper care and management. By observing their physical characteristics and behaviors, you can confidently identify whether your guinea pig is a male or female. Remember, if you are unsure, consult a veterinarian who can provide further guidance and assistance. With the right information, you can create a happy and healthy environment for your guinea pig.

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