How to Determine Between Male & Female Guineas

Determining the gender of a domestic guinea pig helps to prevent unwanted pregnancies. And, knowing the sex of a guinea pig can also guide the pet's owner when looking for symptoms of certain medical conditions that are more troublesome to one gender, like bladder stones or urinary tract infections. Although it might take a more trained eye to determine the gender of newborn guinea pigs, the sooner the sex can be determined the better.

Things You'll Need

  • Guinea pig
  • Table
  • Mirror
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Instructions

    • 1

      Remove the guinea pig from its cage and, with a firm grip, grab it by placing one hand across its chest and another under its rump for support.

    • 2

      Flip the animal over, using a table for support, so that its back is against the table and its abdomen and genital area are exposed.

    • 3

      Examine the genital area closely. According to the Cavy Spirit website, adolescent male guinea pigs have a visible donut shape around their rectum where their testicles are located. The testicles are obvious in older males. On the other hand, females, which also are called sows, typically have a smooth swelling over their genital area and won't exhibit the presence of the testicular sac.

    • 4

      Feel the skin just above the genital area. If you feel a ridge or small lump just under the skin, that usually is indicative of a penis. To know for sure if what you are feeling is indeed the shaft of a penis, press gently above the genital region. The penis should extrude, eliminating all doubt as to whether the guinea pig is a male or female.

    • 5

      Spread open the genital area to look for a Y-shaped formation. According to the Guinea Lynx website, this indicates that the guinea pig is female.

    • 6

      Take the guinea pig to a veterinarian that treats exotic animals for verification if you are unsure. The vet most likely will use the same methods for determining the sex, but the presence of much more skilled hands and eyes should render an unquestionable diagnosis.