When Is A Guinea Pig Too Old To Breed? – Specifics, Sexual Maturity & Time Scales

When breeding guinea pigs, there may be a few questions which you should definitely know the answer to before you start. Seeing as your guinea pigs health should be a top priority, it’s no wonder you’re probably thinking ‘When is a guinea pig too old to breed’.

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If you’ve done any previous research into this topic then you are probably very confused. Every article we’ve come across seems to highlight different ages at which a guinea pig can breed at and too. So we’ll try to make this as simple as possible for you.

Through this article we will highlight all the information you need to know which stems from this question. This is a great question to ask because there are some health concerns for guinea pigs if they are breeding past a certain age. So let’s dive straight in.

At What Age Are Guinea Pigs Sexually Mature?

First of all, you should know when guinea pigs are sexually mature. Both males and females are sexually mature from a seeming young age, however there is a slight difference between the two.


Male guinea pigs, also known as ‘Boars’ are sexually mature from 2-3 months old. It only takes 60-90 days for a male guinea pig to become sexually mature, however if you are breeding from home you should really be waiting until a male is 4 months of age before breeding them. This will give them enough time to fully mature, and have a much better chance of producing healthy pups.

You may have read that male guinea pigs should be at least 34 months of age before breeding. However this isn’t entirely true. The male reproductive system matures around 12-17 weeks of age. Any time before this and their sperm may not be viably healthy.


Female guinea pigs, also known as ‘Sows’ are sexually mature at 2 months of age. So in fact they are sexually mature before the males. However if they are kept with older males, they may try and mate before the female is fully mature which brings serious health risks to the female. Again, you should wait roughly for 3 months before breeding from home.

A female should first be bred before 7 months of age. If the first breeding is put off beyond this time, this is when the serious, and sometimes life threatening problems can occur in delivering the pups. 

What Is The Maximum Age a Guinea Pig Can Breed?

When is a guinea pig too old to breed? In general the maximum age you should breed guinea pigs is 2 years of age, or 24 months. Guinea Pigs may remain fertile until 4 years of age, however with this age comes reproductive complications. This is no different to humans. Past a certain age, or time in our lives, it becomes a health risk to us to reproduce. 

The optimal breeding age for both male and female guinea pigs ranges between 6-24 months. After this age is generally when the reproductive complications start. Ideally, female guinea pigs should be less than 10 months old to give birth naturally and healthily. Litter sizes start to decrease massively and serious health issues can stem from the reproduction.

Male Specificities 

  • Will show sexual behaviours from as early as 4 weeks of age.
  • Unable to produce viably healthy sperm until 12-17 weeks of age.
  • Should be at least 4 months of ages before breeding. (NOT 34 months).

Femle Specificities

  • Must be first bred between 4-7 months of age.
  • The pelvis of females will fuse at an early age if not bred.
  • Early breeding helps for better future breeding.
  • Pups are born large, which offers its own health concerns

Pairing Two Suitable Guinea Pigs 

You should first spend the time introducing the males to the females. Usually this is all be fine, commonly guinea pigs won’t get aggressive towards one another, however it is always good to monitor their progress. 

Once you have monitored their behaviours with each other and feel they are getting along just fine you can not separate these two individuals into a cage of their own. You can now leave this pair together for 20-48 days. The female will be in ‘heat’ roughly every 16 days, so this will give the female three opportunities to become pregnant. ‘Heat’ is the optimal time for a female to fall pregnant.

After the 48 days, it’s now time to separate the two guinea pigs. You should do this to reduce the stress for the female in the next two month of pregnancy. And because after the pregnancy, the male will more than likely want to mate again straight away.

You can in fact put the female back into a group of other females. Most female guinea pigs will act as a second mother to young pups. They will naturally care for them as if they’re their own, and offer no threat to the new born pups.

How Long Does a Guinea Pigs Pregnancy Last?

Guinea Pig pregnancies commonly last between 60 and 72 days. This can vary for each individual and should be monitored closely through this time. Obviously like any pregnancy, there can be occasions when pups are born prematurely. Sometimes this can be completely fine, however I would suggest taking the pups and the female guinea pig to the veterinarian to get checked over, just to make sure there’s no health related issues.

Commonly a guinea pig will have 2 or 3 pups in a litter, but can range all the way up to 8. The record number of pups from one litter is a huge 17.

Females can birth up to 5 litters per year, but should never exceed this number. Female guinea pigs can come back into heat in as little as 15 hours after giving birth, which means they can be pregnant again, whist caring for the previous litter.

For more information, please follow the link below;

How To Tell If A Guinea Pig Is Pregnant?

Will The Males Try To Mate With The Pups?

Unfortunately, yes the males will try to mate with the female pups once they reached sexual maturity if housed together. The males should be removed from the females house and moved back into other housing. They pose a threat to premature pregnancies with their own pups, which may lead to health issues for future pups.

Even new born male and female pups should be separated after roughly 3 weeks, otherwise they may also try to mate with each other once they reach the sexual maturity age. So hopefully you have thought this through before breeding and have adequate housing arrangements and plenty of them.

How Can You Prevent Guinea Pigs From Breeding?

Well, the easiest and most common way to prevent this is kind of obvious. House only females together and males together. Guinea Pigs will be more than happy to be housed with the same sex and rarely fight. They’re communal animals so they like to be around one another. 

You may see a little bit of dominance between the males, but usually this is nothing serious or anything to worry about. Females rarely fight or even argue, they are very peaceful with one another and are usually more caring towards each other. 

If you do have two or more of the opposite sex guinea pigs, then you can get the females spayed or the males neutered. Obviously you have to pay for this, but can be done by any reputable veterinarian. Prices may very for throughout practices.

The guinea pigs may still show some sexual characterises and activities, but they will not be Abe to reproduce after this procedure have been completed. 


We hope you have enjoyed this article on “when is a guinea pig too old to breed”, and were able to find the relevant information needed. 

To recap, guinea pigs should not be bred after 2 years of age. Although they may be fertile anywhere up to 4 years, it is best to keep breeding below 2 years of age. Any time after this is when pregnancy and delivery complication can start.

Females should be first bred between 3-7 months for the best chance of healthy future pregnancies and can then have up to 5 litter a year, until the age of 2 years.

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When Is A Guinea Pig Too Old To Breed? – Specifics, Sexual Maturity & Time Scales

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