Gestation: 59-72 days (average 63)
Guinea pig gestation is 59-72 days (average 63), one of the longest for rodents. Litter size: 1-6 pups (average 2-4). Pups are born precocial — fully furred, eyes open, and eating solid food within hours (unlike rats or mice). Sows (females) should first breed between 4-7 months; if bred after 8 months without prior pregnancy, the pubic symphysis may not separate adequately for birth, requiring a C-section. Pregnancy toxemia (ketosis) is a life-threatening condition in late pregnancy — prevent by avoiding obesity and ensuring constant food availability. Increase vitamin C to 30-50 mg/day during pregnancy. Separate the boar (male) before birth as sows can become pregnant again within hours of delivery.