1. Origins
  2. Classification
  3. Biological and physiological features
  4. Housing and husbandry
  5. Common conditions

Origins

Already domesticated 3,000 years ago by the Incas, the guinea pig was brought to Europe in the 16th century by the Spanish conquistadors. A laboratory animal from the 19th century, then a pet rodent, it is still raised for its meat by the Quechua people of Peru.

Classification

Class: Mammals
Order: Rodents
Suborder: Hystricognaths (Wilson and Reeder), or caviomorphs or hystricomorphs
Family: Caviidae
Genus: Cavia
Species: porcellus
Common name: Cavy, guinea pig

The caviid family includes some fifteen species, all South American: the mara, or Patagonian hare, and the true cavies — genus Cavia, genus Galea, genus Microcavia (mountain cavies), genus Kerodon (rock cavy).

Biological and physiological features

Anatomical features

  • Adult male weight: 500–1,200 g.
  • Adult female weight: 700–900 g.
  • Body length: 20–25 cm.
  • Feet: 4 toes on the forelimbs and 3 toes on the hindlimbs.
  • Dental formula:
Upper jaw 1 0 1 3
I C PM M
Lower jaw 1 0 1 3
Way of life
The guinea pig is active on and off around the clock, day and night, with short bouts of activity and rest of equal length spread across the whole 24 hours. A few crepuscular peaks of activity can also be seen. The guinea pig is not a skilful climber or jumper, and generally does not bite.
Social system
In the wild they are found in colonies of 5–10, active but timid, living in burrows. Living alongside a pet rabbit is possible but rather discouraged. Each male marks out a territory in which it may live with several females and their young. Keeping a guinea pig on its own is prohibited! Behaviour
Communication is by territory marking (anal glands), smell (the nest’s odour) and whistles (a call). It shows contact, dominance–submission and defensive behaviours, and responses to a stimulus.
The guinea pig does not hibernate. Its temperature is 37.2–39.5°C. It lives 4 to 8 years.

Reproductive physiology

Age at sexual maturity:

  • male 10 weeks (300–400 g)
  • female 6 weeks (200 g)

Ideal breeding age:

  • male 3–4 months
  • female 2–3 months, and before 8 months.
  • They can breed all year round. The female’s cycle lasts 15 to 17 days and she has a spontaneous ovulation, which takes place 10 hours after oestrus. Pregnancy lasts 59 to 72 days; about a week before giving birth the pubic symphysis opens up. Beware: 12 to 15 hours after giving birth, the mother can be fertilised again by the male.
  • At birth the babies have their eyes open, already have teeth, and weigh 70–110 g. The mother guinea pig can have 2–3 young and 2–3 litters a year, though she may have 4–5 litters.
  • The babies are weaned at 2–4 weeks of age.
The mother’s milk has the following composition:
  • protein: 8.1%
  • fat: 3.9%
  • carbohydrate: 3%
  • energy: 77 cal per 100 g.

Hand-rearing:

  • 80% whole cow’s milk to be mixed with 20% water and a source of vitamin C (warmed to 38°)

Feeding

The guinea pig is a strictly herbivorous animal; it is also a big eater and a big waster. Its eating habits are quickly set and hard to change afterwards.

  • Hay is its main food; it must have it available at all times. It should be good quality and not dusty.
  • Add vegetables for vitamin C, favouring green leaves (celery sticks, carrot tops, radish tops, aromatic herbs, dandelion…), endive, pepper, cucumber, fennel and so on.
  • Now and then you can give specific complete pellets or mixes.
  • Do not overdo fruit (not every day): apple, pear, strawberry, wild berries. Remove pips and stones.

The guinea pig eats its own droppings.

The guinea pig’s intestinal transit is slow. The food it swallows stacks up in layers along its digestive tract, which is why it must never go too long without eating.

Living environment

  • The cage must be at least 100×50 cm, i.e. 0.5 m² of floor space for 2 individuals, and 0.2 m² more for each extra animal. Ideally the base floor area for 2 to 5 guinea pigs should be 2, or even 4 m². The area can be extended over several levels. For an outdoor enclosure, beware the danger of predators getting in.
  • For bedding you can use hay, straw, bark or fabric. Useful accessories include a shelter, a hay rack, a feeder and a water bowl or an upright bottle, and things to gnaw (hazel or fruit-tree branches). The number of hiding places should match the number of individuals. No steep ramps.
  • To be at its best, the cavy needs an ambient temperature between 18 and 24°C; it should not, however, fall below 10°C or rise above 32°C.
  • The lighting period should be 12 to 14 hours, with an artificial light intensity of 30–40 lux.
  • Humidity is 50%, but can range between 30% and 70%.

Handling

  • Encircle the body with one hand, taking care not to compress the ribcage; the other hand supports the hindquarters in heavy individuals or pregnant females.
  • The cavy rarely bites and is easy to handle, but it is easily frightened.

Common conditions

Dental disorders: dental malocclusion (incisors and/or molars), dental abscess, incisor fracture

Digestive-system disorders: diarrhoea, dysbiosis, gastric dilation, intestinal stasis, parasitosis

Skin disorders: fungal infection, mange and other parasites (lice…), pododermatitis

Respiratory disorders: rhinitis, pneumonia

Reproductive disorders: ovarian cysts, infertility of physiological or infectious origin, mortality of infectious or other origin (toxaemia, dystocia, etc.), abandonment of the young and cannibalism (poor husbandry, first-time dam), mastitis.

Urinary disorders: cystitis, urolithiasis, chronic kidney failure, interstitial nephritis.

Ear disorders: otitis media, after-effects of upper respiratory tract infections, otitis interna, a head tilt.

Eye disorders: bacterial conjunctivitis, corneal inflammation from vitamin A deficiency, corneal ulcer, stromal necrosis, cataract.

Tumours: lymphosarcoma, myeloid leukaemia, lymphoma, pulmonary adenoma, skin tumours, mammary tumours (fibroadenoma), uterine tumours often associated with ovarian cysts.