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When Is The Best Age to Breed Guinea Pigs? (For Females & Males)


Apr 4, 2023
close up of a brown and white guinea pig


close up of a brown and white guinea pig

Guinea pigs reach maturity pretty quickly. However, the best age to breed them can vary slightly from animal to animal. The guinea pig’s health should be of utmost importance, and not all guinea pigs will be healthy when they reach maturity. The ideal breeding age for female and male guinea pigs is between 4 and 6 months


When Do Guinea Pigs Reach Maturity?

Female guinea pigs can reach sexual maturity at as young as 4 weeks. However, breeding them at such a young age isn’t recommended, as this can cause health issues. These animals often aren’t done growing, so they may not be completely able to carry a litter. Getting pregnant this young can result in complications and stunted growth.

Instead, the ideal breeding age for a female guinea pig is between 4 and 6 months. This allows them plenty of time to grow and mature before they carry a pregnancy. Breeding them earlier can make it hard for them to give birth, which can be life-threatening.

Males can be bred at around the same age. Waiting until 4 months ensures they are fully developed and mature enough to mate.

You should breed females before they are 8 months old, however. Waiting longer than that (for guinea pigs you intend to breed) can lead to problems later in future pregnancies.

With that said, you should only breed guinea pigs if you’re aware of the implications of breeding them. It’s important to keep the health of the mother and offspring in mind. You should also have an established relationship with a veterinarian, as the female may need veterinary care.

Two Guinea pigs under the rocks
Image Credit: Petra, Pixabay

What Age to Breed Female Guinea Pigs

As we’ve discussed, you should wait until around 4 to 6 months to breed female guinea pigs. For the most part, this is because it allows her to mature completely before breeding. However, there are other potential downsides to breeding too early, as well:

  • Increased risk of pregnancy complications: Female guinea pigs bred too early could have trouble giving birth and might need medical help. The mother and the child may end up in a stressful scenario that could endanger their lives.
  • Stunted growth: If a female is bred too early, energy and nutrients will be put towards the offspring—not the mother. Without very careful nutrition, this can lead to stunted growth, which can lead to tons of problems down the line. Furthermore, this isn’t reversible.
  • Behavioral problems: Females bred too early are less likely to care for the offspring properly and may develop behavioral issues. For instance, she may become aggressive and territorial, as she may not be socialized enough before being bred.
  • Increased health problems: Females are more likely to develop health issues during and after pregnancy if they are bred too early, as their bodies won’t be mature enough to handle the pregnancy.

That said, 4 months isn’t old enough for all guinea pigs. Some may need to wait until 6 months. It is best to wait until female guinea pigs are fully mature and have reached a healthy weight and size before considering breeding them. This will help ensure their overall health and welfare, as well as the health and welfare of their offspring.

What Age to Breed Male Guinea Pigs

You should also wait until about 4–6 months to breed a male guinea pig. There are several reasons for this, including:

  • Sexual maturity: Males often reach sexual maturity around 4 weeks. However, some don’t reach sexual maturity until around 6 weeks. Therefore, often, you have to wait past a minimum of 4 weeks anyway.
  • Health problems: Males may become injured during breeding if they are too young, as they may not be fully grown. A 4-week-old male and a 6-month-old female may have considerable size differences, putting him in danger.
  • Behavioral problems: Breeding a male too early can lead to behavioral problems, like aggression. Often, this is due to breeding without proper socialization beforehand, as it can be hard to properly socialize a male if you breed them very early.
  • Compatibility: You must ensure that a male is compatible with a female before breeding, which takes time. Therefore, it’s often not possible to rush into breeding as soon as the male is sexually mature.
  • Genetic problems: The male’s genetic issues may not be apparent initially. Therefore, providing a few extra months of maturation can help ensure the male is healthy with good genetics before breeding him.
Two guinea pigs on the grass
Image Credit: Charleen Magne, Shutterstock


Factors to Consider

There are several factors you should consider before you breed guinea pigs. Not all guinea pigs are ready to breed at the same time. Therefore, you must be cautious and consider your guinea pig’s health and development.


Guinea pigs need to weigh their adult size before they are bred. Therefore, you must wait until the guinea pig is fully grown to breed, especially for females. While males don’t necessarily have to be their full size, ensuring they are safe while mating is often recommended. Otherwise, the female may injure them.

Often, this takes at least 4 months. However, larger guinea pigs may take up to 6 months. Of course, this assumes the guinea pig is a healthy weight for its size—not overweight.

Little curious guinea pig on green grass
Image Credit: AnastasiaPash, Shutterstock

Overall Health

The guinea pig should be healthy before breeding. The animal shouldn’t have any underlying illness or conditions, especially genetic ones, that could be passed onto its offspring. If the guinea pig is sick, the pregnancy may not be healthy.

Therefore, you may have to wait until the guinea pig is completely healthy before moving forward.


Guinea pigs should be completely socialized before they are bred. This ensures that they don’t regress into aggression and territorial behaviors after breeding and helps ensure that pregnancy complications can be handled appropriately.

While you can socialize a guinea pig in 4 months, not all guinea pigs will be socialized then. Therefore, you may have to wait until your guinea pig is friendly and well-socialized before breeding—even if that means waiting another month or two.

Portrait of cute red guinea pig. Close up photo
Image Credit: Dev_Maryna, Shutterstock


Some guinea pigs take longer to develop than others due to their genetics. Therefore, some guinea pig lines may simply need to wait longer before they are bred. Often, this is related to size, as larger animals often take more time to mature. However, this isn’t always the case.

There are also several types of guinea pigs, some requiring more time before breeding.


Final Thoughts

Guinea pigs attain sexual maturity fairly quickly, but the optimal age for breeding can vary depending on the animal. The utmost priority should be given to the guinea pig’s health, as not all will be healthy upon reaching maturity.

Female guinea pigs can reach sexual maturity as early as 4 weeks old. However, breeding them at this young age is not advisable due to potential health complications. As they may still be growing, they may not be able to carry a litter safely, leading to complications and stunted growth. The recommended age for breeding a female guinea pig is between 4–6 months, which allows enough time for proper growth and development before carrying a pregnancy. Breeding them earlier can increase the risk of a difficult birth, which can be life-threatening.

Male guinea pigs can be bred at around the same age. Waiting until they reach 4 months ensures they are physically and emotionally developed enough to mate.

Featured Image Credit: rubyclement, Pixabay

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