Chapter 22: Guinea Pigs

Guinea pigs, scientifically named Cavia porcellus, are rodents from the Caviidae family. Common laboratory varieties include albino Duncan-Hartley and Hartley, as well as tricolor Strain 2 and Strain 13, and the hairless IAF guinea pig.

Table 22.1. Guinea pig biological data.

Body weight (grams)

Adult male: 950–1200

Adult female: 700–850

Newborn: 85–95 (when there are 3–4 young in litter)

Normal body temperature

38.5–39.9 °C

101.3–103.8 °F

Heart rate (beats per minute)

230–380

Respiration rate (breaths per minute)

42–104

Life span (years)

4–5

Daily consumption (per 100 grams body weight)

Feed: 6 grams

Water: 10 mL

Puberty age (weeks)

Male: 8–10

Female: 4–5

Sexual cycle duration

13–21 days

Sexual cycle type (in lab conditions)

Polyestrous, nonseasonal

Gestation period (days)

59–72

Litter size/# of young

2–5

Begins eating solid feed (days)

Male guinea pigs, called boars, are larger than female guinea pigs, called sows. The anus is close to the genitals in both sexes, but the genital papilla is round in males and Y-shaped in females. Apply pressure in pelvic area and penis will protrude

Females should not be bred for the first time after 7 months of age because their pelvic bones may be fused by the time they give birth. Parturition is slow and difficult when the bones are fused, and may be fatal to the mother and the young. If females are bred before 6 months of age, the pelvic bones can move and permit an easy delivery; the animals may then be bred for successive litters.

Guinea pigs, active for long periods with no regular circadian patterns, are susceptible to respiratory diseases and pododermatitis. They require low-dust bedding, a 12:12 light:dark cycle, and frequent cage sanitization due to high urine and feces production.

Guinea pigs require vitamin C in their diet to prevent scurvy. Commercial guinea pig pellets contain the necessary vitamin C, but it is important to check the milling date to ensure the feed is not expired.

Guinea pigs express pain or fear through loud squeals, licking, biting, shaking, and other unusual behaviors. Recognizing these signs is crucial for their well-being.

Guinea pigs are euthanized using CO2, inhalant anesthetics, or barbiturates, with death verified by checking for heartbeat or opening the thoracic cavity. Carcass disposal follows facility guidelines.