page_title: Guinea pig
section_title: Reproduction
hierarchical_section_title: Guinea pig / Reproduction
caption_attribution_description: Picture of a pregnant guinea pig (Cavia porcellus) 1 week before delivering 3 pups
context_page_description: The guinea pig or domestic guinea pig, also known as cavy or domestic cavy, is a species of rodent belonging to the family Caviidae and the genus Cavia. Despite their common name, guinea pigs are not native to Guinea, nor are they closely biologically related to pigs, and the origin of the name is still unclear. They originated in the Andes of South America. Studies based on biochemistry and hybridization suggest they are domesticated descendants of a closely related species of cavy, such as C. tschudii, and do not exist naturally in the wild. They were originally domesticated as livestock, for a source of meat, and continue to be consumed as food.
  In Western society, the domestic guinea pig has enjoyed widespread popularity as a pocket pet, since its introduction to Europe and North America by European traders in the 16th century. Their docile nature, friendly responsiveness to handling and feeding, and the relative ease of caring for them have made guinea pigs a continuing popular choice of household pet. Organizations devoted to the competitive breeding of guinea pigs have been formed worldwide.
context_section_description: Males reach sexual maturity in 3–5 weeks, while females can be fertile as early as 4 weeks old, and can carry litters before they are adults. The female guinea pig is able to breed year-round, with spring being the peak. A sow can have as many as five litters in a year, but six is theoretically possible. Unlike the offspring of most rodents, which are altricial at birth, newborn cavy pups are precocial, and are well-developed with hair, teeth, claws, and partial eyesight. The pups are immediately mobile and begin eating solid food immediately, though they continue to suckle.  Females can once again become pregnant 6–48 hours after giving birth, but it is not healthy for a female to be constantly pregnant.
  The gestation period lasts from 59 days (1.9 months) to 72 days (2.4 months), with an average of 63–68 days. Because of the long gestation period and the large size of the pups, pregnant females may become large and eggplant-shaped, although the change in size and shape varies depending upon the size of the litter. Litter size ranges from one to six, with three being the average; the largest recorded litter size is 17. The guinea pig mother only has two nipples, but she can readily raise the more average-sized litters of 2 to 4 pups. In smaller litters, difficulties may occur during labour due to oversized pups. Large litters result in higher incidences of stillbirth, but because the pups are delivered at an advanced stage of development, lack of access to the mother's milk has little effect on the mortality rate of newborns.
  Cohabitating females assist in mothering duties if lactating; guinea pigs practice alloparental care, in which a female may adopt the pup(s) of another. This might take place if the original parents die or are for some reason separated from them. This behavior is common and is seen in many other animal species such as the elephant.
  Toxemia of pregnancy (hypertension) is a common problem and kills many pregnant females. Signs of toxemia include: anorexia, lack of energy, excessive salivation, a sweet or fruity breath odor due to ketones, and seizures in advanced cases. Pregnancy toxemia appears to be most common in hot climates. Other serious complications during pregnancy can include a prolapsed uterus, hypocalcaemia, and mastitis.
  Females that do not give birth may develop an irreversible fusing or calcified cartilage of the pubic symphysis, a joint in the pelvis, which may occur after six months of age. If they become pregnant after this has happened, the birth canal may not widen sufficiently, which may lead to dystocia and death as they attempt to give birth. Females can become pregnant 6–48 hours after giving birth, but it is not healthy for a female to be thus constantly pregnant.
  Male and female guinea pigs do not differ in appearance apart from general size. The position of the anus is very close to the genitals in both sexes. Female genitals are distinguished by a Y-shaped configuration formed from a vulvar flap. While male genitals may look similar, with the penis and anus forming a similar shape, the penis will protrude if pressure is applied to the surrounding hair. The male's testes may also be visible externally from scrotal swelling.
caption: Pregnant sow one week before delivering three pups
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