1. Mating: Male guinea pigs, called boars, reach sexual maturity at around 2 months of age, while females, called sows, reach maturity around 4-6 months. Breeding can begin once the female is sexually mature.
2. Estrus Cycle: Sows have an estrus cycle, which is the period of fertility. It typically lasts for 12-16 hours and occurs every 15-20 days. During estrus, the sow is receptive to mating and will show signs like increased activity, lordosis (arching her back), and an interest in the boar.
3. Copulation: When a sow is in estrus and receptive, the boar will mount her from behind and insert his penis into her vagina. Copulation usually lasts only a few seconds, but the boar may repeat the process several times.
4. Fertilization: During copulation, the boar ejaculates sperm, which travel through the sow's vagina and cervix into the uterus. The sperm then fertilize the sow's eggs, resulting in the formation of zygotes.
5. Gestation Period: Once fertilized, the zygotes implant into the walls of the uterus. The gestation period in guinea pigs is relatively short, lasting between 59-72 days (approximately 2 months). During this time, the embryos develop into fetuses and the sow's body prepares for birth.
6. Hormonal Changes: Pregnancy in guinea pigs involves significant hormonal changes. Progesterone, produced by the corpus luteum, plays a crucial role in maintaining the pregnancy. Estrogen levels also increase, stimulating the development of the mammary glands in preparation for lactation.
7. Birth (Parturition): As the end of the gestation period approaches, the sow will show signs of impending birth, including frequent urination, nesting behavior (gathering materials to create a nest), and restlessness. The sow usually gives birth to a litter of 1-6 pups (called cavies) at a time. The delivery process is relatively quick, and the pups are born well-developed and able to move around shortly after birth.
After birth, the mother guinea pig will provide care for her pups, including nursing, grooming, and protecting them. Baby guinea pigs are precocial and can start eating solid food within a few days of birth. They are fully weaned by 3-4 weeks of age.