Sexing of guinea pigs

Females (sows): The sows usually have a smooth swelling over their genital area. Sometimes, it can be bumpy looking, making you think it might be a male! If you gently part the genital opening, on a sow, a "Y" shaped opening should appear.


Males (boars): Press gently just above the genital area. If it's a male, you should be able to make the penis slowly extrude. Especially in heavy, older males, the penis can be "tucked away" in folds of skin, looking entirely like a female! You should TRY to get the penis to ease out.