Mating or breeding guinea pigs
Males are called boars and females are called sows. Sows are usually sexually mature at about six weeks of age, but mating guinea pigs is best delayed until at least 12 weeks-old. Boars become sexually mature at about 10 weeks-old.
Unless you are breeding guinea pigs, males and females should therefore be separated or they can be neutered from 12 weeks of age. This procedure requires the guinea pig to come into the vets for a day and normally they can go home the same evening. The procedure happens under general anesthetic and all animals receive pain relief to make them as comfortable as possible.
If guinea pigs do mate, the gestation period varies from 59-72 days with larger litters having a shorter gestation. Litter size can vary from 1-6 piglets but usually is 3 or 4. The sow will be able to mate again within 1-2 days after birth and it is safer to separate pregnant females from other guineas until the litter is weaned.