For sexing your Guinea Pig you have to put it on its back gentle to have a look at it primary genitals. It will not like it and may be a second hand as assistance could help.
Determine male Guinea Pig gender
The male genitals looks like a lower case written “i“with a big dot. The dot is the penis of your Cavy. If you pull with your thumb and index finger carefully on its abdominal region it will come out and you can be 100% sure that this Guinea Pig is a male Guinea Pig. As a layperson you better should not try this because you may hurt your cavy. Before you try this yourself you have to first let you show this by a professional like a veterinerian.
You can sexing a mature Guinea Pig male easily by its testicles who are clearly visible. A already castrated buck does not have any testicles for sure, and a sexually immature Guinea Pig buck has also no (visible) testicles too.
Determine female Guinea Pig gender
The genitals of a female Guinea Pig looks like a lower case “y”. In the middle of the “y” you can spot a small dot. This is its vagina. There is really nothing more to say about this.
False determination: Teats
Teats of Guinea Pigs are not gender-specific. Male and female Guinea Pigs does both have teats and you can not determine the sex to be female because you spotted teatson its body. Human men has nipples also. The reason is that teats by Guinea Pigs are grown up just before the embryo move into one sepcific sex initiated by production of hormones.
Sexual maturity of Guinea Pigs
The sexual maturity is the big point why you have to know the gender as soon as possible. Sexual maturity varies a bit but as a fact you can say: Too fast! A female Guinea Pig can be a mature just after 3-4 weeks. A buck can be mature just 3 weeks after birth. There is another rule of thumb that a Guinea Pig buck with a weight of at least 250g ist mature. At the very latest to this point you have to seperate the buck-child from its mother and all other female cavies. You young male cavy will not be choosy and there is a high risk of new – and incest – pregnancy which may cause serious problems. Also the young female should not be impregnated so far either.You can not determine the sexual maturity by its age only. If your buck is much younger than three weeks but its weight reaches 250g – separate him immediately!
Guinea Pig sex / gender with sample images
These images might help you to find out the gender of your Guinea Pigs.