Rats and guinea pigs are popular small pets that many owners consider housing together. But is this a good idea? In this comprehensive 3000 word guide, we’ll cover everything you need to know about whether rats and guinea pigs can safely cohabitate.

If you’re short on time, here’s the quick answer: rats and guinea pigs have very different care needs and natural behaviors, so housing them together is generally not recommended. Rats may injure, frighten, or even kill guinea pigs if housed in the same cage.

Key Differences Between Rats and Guinea Pigs

Size and Lifespan

Rats and guinea pigs differ in terms of size and lifespan. Rats are generally larger than guinea pigs, with an average length of 9 to 11 inches and a weight of 0.5 to 1.5 pounds. On the other hand, guinea pigs are smaller, measuring around 8 to 10 inches in length and weighing between 1.5 to 2.5 pounds.

In terms of lifespan, rats typically live for 2 to 3 years, while guinea pigs can live for 5 to 7 years.

Behavior and Temperament

Rats and guinea pigs also have different behavior and temperament traits. Rats are known to be highly intelligent and social animals. They are curious, playful, and can be easily trained. Rats enjoy interacting with humans and other rats. On the other hand, guinea pigs are generally more shy and timid.

They prefer a calm and quiet environment and may take some time to warm up to their owners. Guinea pigs are less active compared to rats and are more likely to spend their time eating or relaxing in their habitat.

Habitat and Housing Needs

Rats and guinea pigs have different habitat and housing needs. Rats are excellent climbers and require a cage with multiple levels and plenty of opportunities for exercise and exploration. They also need a solid-bottom cage to prevent injury to their feet.

Guinea pigs, on the other hand, are not natural climbers and prefer a larger, flat-bottom cage with plenty of space to move around. They also need a hiding spot, such as a small hut or tunnel, to provide a sense of security.

It’s important to note that while rats and guinea pigs have their differences, they can still coexist peacefully under the right circumstances. If you’re considering keeping them together, make sure to provide enough space, resources, and supervision to ensure their well-being.

Additionally, consult with a veterinarian or an experienced pet owner for guidance on introducing and managing a multi-species habitat.

Risks of Housing Rats and Guinea Pigs Together

While it may seem convenient or cute to house rats and guinea pigs together, there are several risks involved in doing so. It’s important to understand these risks before considering cohabitation.

Injuries from Rough Play

Rats and guinea pigs have different temperaments and play styles. Rats are known to be more active and can engage in rough play, which may result in injuries to the guinea pig. Guinea pigs, on the other hand, are generally more passive and may be easily overwhelmed by the energetic nature of rats.

This power imbalance can lead to accidental injuries, such as bites or scratches, which can cause significant harm to the guinea pig.

Transmission of Illness and Parasites

Rats and guinea pigs can carry different diseases and parasites that can be transmitted to one another. While both species can be carriers of certain illnesses, they may not necessarily show symptoms. This means that even seemingly healthy animals can spread diseases to their cagemates.

Additionally, rats are known hosts for parasites such as mites and lice, which can easily transfer to guinea pigs. These health risks should not be taken lightly, as they can have serious consequences for the well-being of both animals.

Stress from Incompatible Behaviors

Rats and guinea pigs have different social structures and communication methods. Rats are highly social animals that thrive in groups, while guinea pigs are more solitary creatures. The incompatible behaviors and communication styles of these species can cause stress and anxiety for both animals when housed together.

This can lead to behavioral problems, decreased appetite, and overall decline in their well-being.

It is strongly recommended to house rats and guinea pigs separately to ensure the safety and well-being of both species. While they may be adorable to watch, the potential risks outweigh any perceived benefits of cohabitation.

Providing each species with their own appropriate living environment will allow them to thrive and lead happy, healthy lives.

Exceptions and Potential Solutions

While it is generally not recommended to house rats and guinea pigs together due to their different social structures and communication methods, there are some exceptions and potential solutions for those who still wish to give it a try.

Careful Introductions

One potential solution is to introduce the rats and guinea pigs to each other gradually and carefully. This involves creating a neutral territory where both animals can explore and interact with each other under close supervision.

By allowing them to get used to each other’s scent and presence in a controlled environment, you can assess their reactions and determine if cohabitation is feasible.

It is important to note that not all rats and guinea pigs will get along, even with careful introductions. Some may display aggressive or territorial behavior, which can lead to potential harm. It is crucial to closely monitor their interactions and be prepared to separate them if necessary.

Separate But Adjoining Enclosures

Another potential solution is to house the rats and guinea pigs in separate but adjoining enclosures. This allows them to have their own space while still being able to see and interact with each other through a mesh divider or glass barrier.

This setup can provide some level of socialization and companionship without the risk of physical harm.

It is important to ensure that the enclosures are secure and escape-proof, as both rats and guinea pigs are known to be clever escape artists. Additionally, each enclosure should be appropriately sized and equipped with the necessary amenities and enrichment items to meet the specific needs of each species.

Strict Supervision

If you decide to house rats and guinea pigs together, it is essential to provide strict supervision at all times. This means closely monitoring their interactions, especially during the initial stages of cohabitation.

It is crucial to intervene immediately if any signs of aggression or stress are observed.

Furthermore, it is important to regularly assess the well-being of both animals and provide them with individual attention and care. This includes ensuring they have separate feeding areas and providing them with species-specific diets that meet their nutritional requirements.

It is worth mentioning that the success of housing rats and guinea pigs together can vary greatly depending on the individual animals involved. Some may form unlikely friendships and coexist peacefully, while others may never be compatible.

It is always recommended to prioritize the safety and well-being of both animals when considering cohabitation.

For more information on the compatibility of rats and guinea pigs, you can visit the following websites:

Tips for Proper Housing

Cage Size Requirements

When considering housing options for rats and guinea pigs, it is important to provide them with adequate space to live comfortably. Both rats and guinea pigs are active animals that require room to run, play, and explore.

For rats, a minimum cage size of 24×12 inches is recommended, while guinea pigs need a larger space of at least 7.5 square feet for one guinea pig, and an additional 2.5 square feet for each additional guinea pig.

It is worth noting that while rats and guinea pigs can cohabitate, it is essential to provide each species with their own separate living areas within the cage. This will ensure that they have their own space to retreat to and minimize the risk of territorial disputes.

Best Bedding Options

Choosing the right bedding is crucial for the health and well-being of both rats and guinea pigs. For rats, it is recommended to use a bedding material that is absorbent, such as shredded paper or aspen bedding.

Avoid using pine or cedar bedding, as the strong aroma can be harmful to their respiratory systems.

Guinea pigs have more sensitive respiratory systems compared to rats. It is best to opt for bedding made from natural materials like paper or straw. Avoid using bedding made from wood shavings or sawdust, as they can lead to respiratory issues for guinea pigs.

Ideal Location in Home

When deciding on the location for the cage, it is important to choose a spot that is quiet and away from direct sunlight or drafts. Rats and guinea pigs are sensitive to temperature changes, so it is best to keep their cage in a room with a consistent temperature.

Additionally, consider placing the cage in an area where they can still be a part of the family’s daily activities. While they may not appreciate loud noises or constant disturbances, being able to observe and interact with their human companions can provide mental stimulation and socialization.

Remember, each animal has different needs and preferences, so it is important to observe their behavior and adjust their living conditions accordingly. Providing them with a spacious and comfortable living environment will contribute to their overall well-being and happiness.

Signs of Stress and Incompatibility

When considering keeping rats and guinea pigs together, it is important to be aware of the signs of stress and incompatibility between these two species. While some rats and guinea pigs may get along well, it is not always the case. Here are some signs to watch out for:


Aggression is a clear indication that rats and guinea pigs are not compatible. Rats are known to be more territorial and may exhibit aggressive behaviors towards guinea pigs, such as chasing, biting, or even causing injuries.

Guinea pigs, on the other hand, may become frightened and stressed in the presence of an aggressive rat. If you notice any signs of aggression, it is best to separate them immediately to prevent any harm.

Excessive Hiding

If you observe your guinea pig constantly hiding or seeking refuge from the rat, it may be a sign of stress and discomfort. Guinea pigs are naturally prey animals and may feel threatened by the presence of a predator-like rat.

They may retreat to their hiding spots more frequently and avoid interaction. This behavior indicates that the two species are not compatible and should be kept separately to ensure the well-being of both animals.

Lack of Activity

A lack of activity and decreased appetite in either the rat or the guinea pig can be a sign of stress and incompatibility. If one of the animals is constantly stressed or fearful in the presence of the other, it may lead to a decrease in their overall well-being.

They may display signs of lethargy, loss of appetite, or lack of interest in their surroundings. It is crucial to monitor their behavior closely and separate them if necessary.

It is important to remember that individual personalities and temperaments can also play a role in the compatibility between rats and guinea pigs. While some may coexist peacefully, it is always better to err on the side of caution and prioritize the safety and comfort of both animals.

For more information on rat and guinea pig compatibility, you can visit www.petmd.com for expert advice and guidelines.


While rats and guinea pigs may seem like good cagemates, housing them together often ends badly. Their differing needs and behaviors make cohabitation challenging and stressful in most cases. With proper precautions some owners have success housing these rodents together, but extreme care must be taken.

In general, it’s safest to keep rats and guinea pigs in separate enclosures to ensure their health and wellbeing.

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