Guinea Pig

Guinea pig（圖片來源：Gzen92，採用 CC BY-SA 4.0 授權）

The guinea pig (Cavia porcellus), often referred to as a cavy or guinea pig, is a rodent belonging to the family Caviidae. It originates from the grassland regions of the Andes in South America. More than five thousand years ago, Indigenous peoples in this region had already domesticated these animals. At that time they were primarily raised as a source of meat rather than as pets. It was not until the sixteenth century, when European explorers brought them back to Europe, that guinea pigs gradually became popular among aristocratic and upper-class households. Because of their gentle temperament, they soon spread across the world and became widely kept companion animals.

In the wild, guinea pigs typically inhabit open grasslands. They live in small social groups and feed mainly on vegetation. They do not dig their own burrows but instead take shelter in abandoned burrows made by other animals or hide among dense vegetation to avoid predators. Their activity peaks during the early morning and evening, allowing them to avoid the higher risks associated with daytime exposure. Guinea pigs are naturally timid but also highly alert. When threatened, they may freeze in place or scatter quickly to escape danger. When they feel safe and content, they sometimes perform small, sudden jumps into the air. This behavior is commonly known as “popcorning,” a display that reflects excitement or happiness.

Physically, guinea pigs have a compact, rounded body and a tail that has almost completely disappeared through evolutionary reduction. Their four incisors grow continuously throughout life, so they must constantly chew fibrous foods to wear them down. Most individuals weigh between about 700 grams and slightly over 1 kilogram. Their average lifespan ranges from four to eight years, although individuals kept under excellent care may live more than ten years. Guinea pigs are highly social animals; both in the wild and in captivity they thrive better when kept in pairs or small groups, which helps reduce loneliness and stress.

Guinea Pig Vocalizations:

Guinea pig（圖片來源：Kacper Aleksander，採用 CC BY-SA 4.0 授權）

Housing Requirements in Captivity

Keeping guinea pigs in a household environment requires providing a clean, spacious, and secure living area. The enclosure should not be too small. At least one square meter of floor space is recommended for two guinea pigs to live comfortably. Larger enclosures are even better, allowing the animals greater freedom of movement. Because guinea pigs are not skilled climbers or jumpers, the enclosure does not need to be tall. However, the floor must be solid and flat. Wire mesh flooring should be avoided because it can easily injure their feet and lead to ulcerative conditions.

Suitable bedding materials include paper-based bedding, wood shavings that do not contain harmful essential oils (pine and cedar should be avoided), or commonly used fabric liners and absorbent cloth pads. The enclosure should be placed in a well-ventilated area where there is no direct draft. Direct sunlight and high temperatures should also be avoided.

The ideal environmental temperature for guinea pigs is approximately 18 to 24°C. Temperatures exceeding 30°C can easily lead to heatstroke, with pregnant females being particularly vulnerable. During summer, special attention must be paid to preventing overheating, while in winter exposure to cold conditions should be minimized.

The enclosure should also contain hiding places such as small wooden houses, tunnels, or cardboard boxes. These structures provide security because guinea pigs are naturally cautious animals and may become stressed when they feel exposed. The enclosure should be cleaned daily, and bedding should be replaced regularly. Guinea pig urine contains ammonia, and if it accumulates it can harm respiratory health.

Whenever possible, guinea pigs should also be allowed a period of supervised activity outside the enclosure each day. This opportunity for exploration satisfies their natural curiosity and promotes physical exercise and overall health.

Feeding Conditions

Guinea pigs are herbivores, and their daily diet should be based primarily on hay. Dried grasses, especially timothy hay (Phleum pratense), should be available at all times. Continuous access to hay helps wear down their teeth and supports healthy intestinal movement.

For young guinea pigs as well as pregnant or nursing females, alfalfa (Medicago sativa) may be offered because it provides additional protein and calcium. However, adult guinea pigs should not consume large amounts of alfalfa over long periods, as it may lead to obesity or urinary stones.

In addition to hay, high-quality guinea pig pellets can supply essential vitamins and minerals. Mixed feeds that contain seeds, nuts, or sweetened pellets should not be used as a staple diet. These ingredients often produce nutritional imbalance and encourage selective feeding behavior.

Unlike most rodents, guinea pigs cannot synthesize vitamin C on their own. A deficiency can result in scurvy. Therefore fresh vegetables must be provided daily to supply vitamin C. Suitable options include bell peppers, kale, celery leaves, and small amounts of spinach. Fruit should only be given occasionally because of its high sugar content, typically once or twice per week. Common choices include apples or grapes.

Fresh fruits and vegetables must be thoroughly washed before feeding, and any uneaten portions should be removed within a few hours to prevent spoilage and health problems.

Clean drinking water should always be available. Mineral water or boiled, dechlorinated water may be used. Water bottles attached outside the cage help prevent contamination. Some guinea pigs prefer drinking from a bowl, but bowls can easily be tipped over or soiled, so they require frequent monitoring. Caretakers should also observe changes in appetite carefully. When a guinea pig stops eating, its health can deteriorate rapidly, and veterinary care should be sought promptly.

Breeding Conditions

Guinea pigs have a strong reproductive capacity. Males may reach sexual maturity as early as three to five weeks of age, and females can become pregnant at around four weeks. The gestation period lasts approximately sixty days, and each litter typically contains two to four offspring.

Unlike most rodents, newborn guinea pigs are relatively well developed. They are born with fur, their eyes open, and they are capable of walking and eating solid food soon after birth, although they still rely on nursing for a period of time.

Although reproduction is biologically straightforward, casual breeding is not recommended for inexperienced owners. Frequent pregnancies place considerable physiological stress on females and may lead to complications such as eclampsia, dystocia, or even death. If a female experiences her first pregnancy after about six months of age, the pubic symphysis may already have fused, preventing the birth canal from expanding properly and greatly increasing the risk during delivery.

Another concern is the responsibility of caring for and placing the offspring. Large litters can quickly become difficult to manage, and without a responsible adoption plan they may contribute to abandonment problems.

For these reasons, breeding should generally be avoided unless conducted by experienced breeders with proper planning. Neutering is often the most responsible option. It prevents accidental pregnancies and can also reduce aggressive behavior among males as well as the risk of ovarian cysts in females. If pregnancy does occur, caretakers should provide a nutritious diet, a calm environment with minimal disturbance, and be prepared to seek veterinary assistance in case of complications.

Preventing Invasive Spread

Although guinea pigs originate from South America, their popularity as pets has led to their distribution across the world. Because they reproduce quickly and consume large amounts of vegetation, abandoned or escaped individuals in non-native environments may potentially threaten local ecosystems. For example, they may compete with native small mammals for ecological resources.

Therefore pet owners must follow the principle of never abandoning or releasing animals into the wild. Responsible ownership includes providing lifelong care. If keeping the animal is no longer possible, it should be transferred through legal animal shelters or rehomed responsibly with another caretaker, rather than being released outdoors.

Anyone considering keeping guinea pigs should carefully evaluate their ability to provide long-term care before acquiring them, and once they are adopted the responsibility for their welfare should be taken seriously.

Author: Shui-Ye You