Guinea Pigs

Biological data

Life span 4 – 8 years
Adult bodyweight Male: 75g – 1.2kg
Female: 75g – 1.2kg
Sexual Maturity Male: 8 – 10 weeks
Female: 4 – 6 weeks
Gestation period 59 – 72 days (depending on litter size)
Litter size 1 – 6 (average 3 – 4)
Birthweight 60 – 100g
Weaning age 3 weeks


You should keep Guinea pigs in a hutch (allowing at least 0.9m2 per adult guinea pig) with a large run attached or a separate pen for exercise and grazing, ideally multiple hides should be available. Guinea pigs may gnaw through wooden hutches unless the wooden panels are protected by wire mesh. Sawdust/hay as bedding are recommended and hutches should be cleaned 2-3 times per week.


Complete pelleted diets are recommended to prevent selective feeding and to ensure they receive a balanced diet. Hay and grass must be available ad lib and fresh vegetables offered. It is essential that Guinea pigs receive an adequate intake of vitamin C as they cannot synthesise it. Commercial diets are supplemented with Vitamin C, but the shelf life is short and must be kept cool and in the dark. Water should be provided either in bowls or bottles and changed daily

Common Problems

  • Diarrhoea – can be caused by Pseudotuberculosis, Coccidia, Salmonella, Candida or after treatment with antibiotics.
  • Respiratory problems –Bacterial pneumonia – signs include discharge from eyes and nose followed by breathing problems. Animals may respond to antibiotics if started early.
  • Bladder problems – cystitis is relatively common in Guinea pigs can also develop bladder stones, which may need to be removed by surgery. Male Guinea pigs can get plugs blocking their urinary tract which can be gently removed.
  • Scurvy – caused by vitamin C deficiency. Signs include lameness, a shuffling gait and other symptoms. This can be prevented by pelleted Guinea pig diet.
  • Parasites –mites and lice cause irritation and baldness.
  • Abscesses – form bite wounds/trauma require antibiotics and opening up or removal..
  • Ulcerated feet – usually associated with rough cage flooring, poor hygiene, over-weight older animals.
  • Baldness – seen in females in late pregnancy and after birth. It can also be caused by ovarian cysts.
  • Ringworm – causes baldness and scaling especially around the ears.
  • Ear Disease – middle ear disease is quite common and signs are head tilting, circling or loss of balance. Treatment with antibiotics is occasionally successful.
  • Diabetes – symptoms are excessive thirst, weight loss and cataracts. Spontaneous remission can occur.
  • Dental Problems – the incisors, molars and premolars of Guinea pigs grow continuously and overgrowth and maligned teeth are common. They may be caused by inherited defeacts, lack of fibre in the diet or lack of vitamin C. signs are weight loss, poor appetite and dribbling.
  • Eye Problem –corneal ulcers are common and usually caused by hay, straw or sawdust getting trapped in the eye.
  • Birthing Problems – Guinea pigs should never be allowed to become pregnant for the first time until they are skeletally mature. The mother will be unable to have the babies naturally if this occurs, as the pelvis will be too narrow. She would require a caesarean.