cavymadness: guinea pig care and gifts

care links:    home    food    habitats    health    boys & girls    cavy life
These care pages serve as a basic overview of guinea pig care.
More in-depth information can be found through the CavyMadness Facebook community
and via excellent care pages listed on my links page.

boys and girls
(and the social life of guinea pigs)

boy or girl?
sexual maturity and breeding
compatibility and separation anxiety

How do I determine the sex of my guinea pig? — This is probably the most frequently asked question among new guinea pig owners. Sexing young guinea pigs can be difficult, but it's not impossible. It's also not infallible; I adopted female guinea pig that was roomed with another "female" guinea pig - confirmed by an expert. However, I flipped both over, and WHOA, one was a boy! So, if you have a young piggy, check once, and then check again in a week or so. Heck, check again in another week or two; there have been cases where boys turned out to be girls, and vice versa.

is it a boy or a girl?

Male guinea pigs (boars) have testicles, which develop at a fairly young age. In babies, the testicles are not quite apparent, but it is still possible to decode their gender. Look at the genitals. Is there a faint "pucker" of skin? That is the retracted penis. If you press gently (and I do mean gently; this is a sensitive area, after all) above this doughnut-shaped area, you'll feel a small muscle spasm and a tiny little penis will pop out. This process is uncomfortable to the guinea pig, and he may squirm. Make sure you give him a treat for this ordeal!


Female guinea pigs (sows) will have a "Y" shaped genital region, right next to the anus. If you look closely, you will notice that the genitals and the anal opening appear to be almost one and the same, due to the folding of the skin. Female guinea pigs are relatively flat, compared to male guinea pigs, but that's not enough of a distinction to make when you're trying to tell boys from girls. has an excellent page on sexing guinea pigs, complete with detailed photos indicating how to properly determine the gender of your piggy.

It is important to determine the gender of baby piglets as early as two weeks of age, since mating can occur as early as 3-4 weeks, and males need to be separated from females.

sexual maturity and breeding

I do not discuss breeding on this site because it is better left to experts with the experience to handle complications, large numbers of guinea pigs, and medical issues.

Many beginners don't realize that guinea pigs reach sexual maturity quite early. Males are sexually active as early as 3 weeks, and should be observed closely. Males that exhibit behavior such as mounting should be promptly separated from the mother and any females, as they can breed; it only takes a few seconds for a sow to become pregnant. Females can stay with the mother as long as needed. Guinea pigs can generally be separated from their mother at four to five weeks. Note that I will not, and can not, address questions about breeding. GuineaLynx has an excellent, informative page that explains the risks and logistics of breeding.

compatibility and separation anxiety

I was very upset the day that I had to put a divider in my girls' pen because Cordelia started having some dominance issues with just about everyone in the herd. Normally guinea pigs are herd animals, but sometimes it just doesn't work.

Separating a male guinea pig from another male, or a male from the rest of a female herd, or just a piggy with a solo personality is difficult. But guinea pigs can talk to each other through a barrier; I set up a panel of wire shelving so that Cordelia would see, smell and talk to the others without biting.

It is difficult to imagine the docile guinea pig as a territorial animal, but some guinea pigs will not get along, no matter how ideal the setup. Two guinea pigs fighting is a very frightening spectacle; if you ever catch your guinea pigs being aggressive, have a towel ready. Throwing a towel over two fighting guinea pigs will distract and confuse them long enough for you to remove one to a safe place. NEVER put your hands near aggressive guinea pigs; you will definitely be bitten, and an angry guinea pig bites very, very hard and fast.

Generally, some groupings of (non-mating) guinea pigs work well. For instance:

  • All females, given that the hierarchy is defined and there are no disputes
  • One neutered male with a harem of females
  • Two males who were littermates, or who have been together since they were very young (but sexual maturity will bring a test for dominance, so be careful). Note that neutering males won't necessarily make them buddies.
  • An older male with a much younger male
  • Two males that are mellow, as long as one has not mated with a female recently (males have a high risk of fighting if a female or her scent is present)
If you find yourself in a position where you must separate a guinea pig from the rest of your herd, try to keep them as close as possible without causing stress or harm. A friend of mine has eight boys, all in pairs, trios or singly, depending on their personalities. When one recently died, she tried to mix up the pairings to see who would get along with who. Her boys' personalities range from mellow to downright hostile. Remember, personality matters more than gender in terms of compatibility.


This is a delicate topic, since most exotics vets do not have the expertise to perform this procedure without risks. I generally would not neuter a guinea pig unless absolutely necessary. However, that pressing issue of having one male among females brings up the question of neutering in order to keep a male as part of the guinea pig colony.

First, be aware of the risks involved. I was lucky enough to find an excellent vet when, in 1995, I had to get a companion for Basil when I had a full-time job. We neutered Basil, and carefully monitored his progress. He abscessed, but the vet had arranged for two post-op visits to monitor his progress. Basil healed nicely, and he and Emma became a cute little couple for several years. However, I have heard countless stories that did not have such a happy ending.

If you decide to pair a male with one or more females, and want to neuter him, research vets carefully. Be aware that after the surgery, he will need soft towels and supervision. He may very well end up on antibiotics, so you should understand the needs of administering a probiotic to balance the gut flora. Guinea pigs are excellent healers, but any invasive procedure needs to be handled with great care and concern. CavySpirit's neutering page is an excellent reference for learning about the risks involved with neutering.

Signs that your vet will be able to sucessfully neuter your guinea pig:

  • a history of successful guinea pig neuters-- not just two or three; a lot.
  • automatically schedules one or two post-op visits to monitor healing.
  • suggests flora replacement, via Bene-Bac or other probiotic, as part of the antibiotic plan.
  • has good feedback from others (check around on lists, messageboards, etc).
  • will be up front about risks, and won't pass the procedure off as "basic/simple."
  • will tell you that abscesses are common after invasive procedures, and will prepare you for proper aftercare.

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care links:    home    food    habitats    health    boys & girls    cavy life
These care pages serve as a basic overview of guinea pig care.
More in-depth information can be found through the CavyMadness Facebook community
and via excellent care pages listed on my links page.


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