When Is a Guinea Pig Too Old to Breed?

Guinea pigs make wonderful pets. These docile creatures love to socialize and play. You can spend hours watching them run around their enclosure and squeak at each other. Each one has a unique personality, and they do some silly things. Not only are they entertaining, but they are lovable, too.

Guinea pigs respond well to soft voices, gentle touches, and plenty of attention.

Guinea pigs are domesticated members of the rodent family bred to have a calm demeanor and thrive in captivity. Guinea pigs live for several years and reproduce effortlessly. This makes them excellent pets. Many people will purchase a breeding pair, just to raise additional pets.

When Is a Guinea Pig Too Old to Breed?

Because female guinea pigs have a joint called the pubic symphysis located between the two pubic bones of their pelvis that stiffens upon reaching adulthood, it is not advised that they be bred after 8 months of age as complications could occur.

While it is possible for guinea pigs to give birth until they reach four years of age, it is not safe. After guinea pigs age, there is a danger of pelvic damage, blood loss, or deformity in the babies.

Experts state that anytime before 8 months old is the best time to breed guinea pigs due to the aforementioned stiffening of the pubic symphysis.

As the animal gets much older than this, vital systems start to shut down, just as they do in geriatric adults, and giving birth at an advanced age can irreparably harm the female guinea pig. It is possible for guinea pigs to have up to five litters in a year, but you should not breed your guinea pigs that often.

The first litter will likely be only 1 or 2 pups, but each litter after that will be larger. Some guinea pigs have given birth to 8 pups at one time. This is not only hard on the sow’s body, but it is likely some pups will die from lack of nutrition.

The sow should have her first litter before reaching 8 months after being conceived. Sometime after this 8 month mark, the pelvic bones will fuse together if the sow has never had pup, and giving birth after the bones fuse can cause injury or death.

At What Age Can Guinea Pigs Reproduce?

Guinea pigs mature rapidly. Male pups, called boars, begin to show interest in sexual activity as young as 4 weeks old. They cannot produce viable sperm until they are 12 weeks old, however.

Females are capable of reproduction at 4 months old. Experts do not recommend breeding them at such a young age, though, because their bodies are not mature enough to handle the delivery of the pups.

You can breed the female when she is 6 months old. The female will come into heat every 16 days. By placing a compatible male and female in an enclosure together for 45 days, you can ‌ almost guarantee that a pregnancy will result.

After the 45 days, remove the male from the cage, as he will continue to want to breed every time the female has a heat cycle. If it is easier, you can remove the female from the cage and place her in a cage with other females.

How Many Weeks Are Guinea Pigs Pregnant?

The gestation period for guinea pigs is between 60 and 75 days from ‌fertilization. Unless you know the exact date that she became pregnant, ‌keep a close eye on her to determine when it is time for the babies to arrive.

A pregnant guinea pig may appear fatter than she was, less playful or social, and want more alone time. If this is her first litter, give her some space and let her body adjust. Avoid handling her as she may wiggle from your grasp and fall.

This could injure her or her unborn babies. About a month after the suspected breeding, you can lay your fingers on her stomach. Do not press down. If you feel little lumps, she might be pregnant. If the little lumps are moving around, then you know she is pregnant.

When she is getting ready to give birth, the sow will pile shavings into a nest in a corner. She will not want to be bothered and might not eat much. It is important to make sure she eats and drinks. Offer her green leafy vegetables and treats like carrots or apples.

Should I Separate the Pregnant Guinea Pig From the Male?

Yes, remove the male from the cage after he and the female have been together for 30 to 45 days. As long as he is with her, he will want to breed every time she has a heat cycle. Once she becomes pregnant, he could injure her or the unborn pups.

She may also become aggressive towards him, which could lead to aggression toward other guinea pigs and even humans.

You never want to have an adult male around newborn pups when the mother is present. The mother needs to be attentive to the babies, and the male will likely cause her distress by trying to breed with her.

Female guinea pigs can become pregnant again just 16 hours after the pups are born. If you allow this to happen, you jeopardize the lives of the female and the pups who need their mother’s milk to survive.

You also need to separate the male and female pups when they are about three weeks old, before they show interest in each other sexually. You never want to allow males and females from the same litter to breed with one another.

That is called inbreeding. It will cause miscarriage, stillborn pups, or deformed pups.


Guinea pigs can have pups until they are about 4 years old, but it is dangerous for the animal. If the sow gives birth at an advanced age, physical damage or death could occur.

You should breed guinea pigs when they are between 6 months and 2 years of age. The first breeding should be before the sow is one-year-old because the pelvic bones fuse at about one year of age.

After breeding has occurred, separate the male and female. Watch your female for the next couple of months to be sure she is pregnant. When the time comes to give birth, she will know what to do. It is instinctual.