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Guinea Pigs: How Big Do These Mini Gerbils Get?

Guinea pigs are cute herbivorous small pets, originally existing in the wilderness of the Andes in South America. Since that time, they have been majorly domesticated in western society. Domestic cavies have become very popular due to their docile nature and comical social interactions. Generally characterized by happy clamors to funny eating sounds, cooing, rumble strutting, and occasional ludicrous grumpiness, these gentle animals are also known to engage in frequent guinea pig fights. However, a major issue with these pigs has been their size. Weighing and measuring their sizes is an extremely healthy habit. It ensures the good health of your delicate guinea pigs. Let us know more about how big does a guinea pig get?

How Big Does a Guinea Pig Get?

Wondering how big do guinea pigs get? An adult guinea pig measures around 20-35 cm and weighs between 800 and 1500 gm. They won’t grow anymore, but they can gain weight and appear chubbier due to a change in diet or exercise. Some guinea pig breeds are naturally bigger than others, and the males or boars tend to be slightly larger than the females, also known as sows. While the sows weigh between 1.5-2.5 pounds (700 to 900 gm), the average weight of an adult boar can range from 2-2.6 pounds (900 to 1,100 gm).

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10 Biggest Guinea Pig Breeds

Since their first introduction in the 16th century, people have kept cute guinea pigs as pets, resulting in a series of new breeds. Domestic cavies are adorable little creatures available in different breeds, each having its distinct shape and size. Even though there are specific differences in their overall appearances, all guinea pig breeds mostly share similar behavioral aspects. So let us take a quick look into different types of guinea pigs.  

#1 The American Guinea Pig

Guinea Pigs are the most common breed, characterized by short, smooth coats and come in various colors and patterns. American Guinea Pigs have a harmonious, clownish personality. They are easy to care for and require minimal maintenance.

#2 The Abyssinian

This rather mischievous breed has quite a distinctive look. Despite having a typical fur pattern consisting of 8 to 10 hair whirls, called rosettes, Abyssinians tend to keep themselves clean. They are excellent pets for children or adults who are first-time guinea pig owners. 

Abyssinian Guinea pig Image

#3 The Peruvian

This breed is renowned for its long straight hair, alertness, and innate curiosity. Sometimes almost 20 inches long, the Peruvians require time with grooming. So, some owners opt to cut their hair short to avoid brushing daily. 

#4 The Silkie

Also nicknamed the “Sheltie,” this guinea pig breed has long and smooth hair. The hair around their heads sweeps back rather distinctly, appearing as if it had been purposely slicked back. Their long, shiny hairdo requires diligent grooming and is not recommended for kids.

Silkie Guinea pig image

#5 The Teddy

Sporting a short yet dense coat, this exclusive breed is often described as “wiry” with an upturned nose. Although they might not always be soft like others, their maintenance is relatively more convenient. But due to the nature of their coat, occasional brushing is necessary.

#6 The Texel

This truly remarkable species is much sought after by some of the biggest enthusiasts. Their soft, curly locks appear on their backs and throughout the whole body, including the belly. However, this breed is the most difficult to groom because their hair is the most prone to tangling.

#7 White Crested Guinea Pig

Also known as the American Crested, this breed is rare and unique. These little princes and princesses have a white crowns on their heads. The short, smooth hair makes them easy to groom and great for kids to take care of.

#8 The Himalayan

Also called the Siamese cats of guinea pigs, this breed is considered albino. They are known to have colors on their noses, feet, and ears called “points,” which will start to disappear upon exposure to extreme sunlight.

Himalayan Guinea Pig Image

#9 The Rex

This breed is shorthaired, with hair no longer than 1 cm long. The Rex Guinea Pigs do not have guard hairs, making their fur very wool-like, and their most notable features are long floppy ears with a dense, rough coat. Rex has a grand temperament and loves to be handled and stroked.

#10 Skinny Pig

It is a typically hairless breed of guinea pig. They have minimal fuzzy hair on their muzzles and feet. They were created in the laboratory by crossing hairless rodents with shorthaired strains. However, the dearth of hair on their skin makes them more susceptible to catching a cold very easily.

Some other interesting guinea pig breeds include Alpaca, Coronet, Merino, Ridgeback, and Lunkarya.

Size of Baby Guinea Pigs

Guinea pigs are fully grown at around one year of age. Newborn Guinea Pigs measure around 8-10 cm and weigh between 60 and 140 gm. For a few short weeks, the cheeky pups can fit into the palm of your hand. However, they grow fast and almost double in size after two months. Their weight easily triples within the first 3-5 weeks.

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How to Measure your Guinea Pig?

Measuring the size of your guinea pig is a great technique to track their health and well-being. By checking on their weight regularly, a responsible guinea pig owner can monitor their pet to determine if it is overweight or under. Both these factors are likely to have long-term health implications on your cavy pal. However, this could be a rather challenging task. To gauge their size, the first step is to place your guinea pig on a flat surface.

After holding a ruler, a kitchen scale, or even a tape measure running parallel to your pet’s body, measurements should be taken from the tip of its nose to the rear end. Since drafting an exact measurement is daunting, a more or less approximate idea is plentiful and good to go. However, to accomplish this, you should distract your playful pal with a treat or two and some of your daily dose of affection.

Factors Affecting the Size of Guinea Pigs

Like any other living species, the size of a guinea pig is majorly dependent on a couple of factors discussed below. 

#1 Gender

The very first evident element affecting their growth has to be the gender of a guinea pig. As has already been mentioned, the boars tend to be substantially larger than their fellow sows, notwithstanding the breed. However, they would eventually cease to grow after a certain time. Gender plays quite a role in guinea pigs.

Female Guinea Pig Image

#2 Diet or Nutrition

The next most obvious factor would be Guinea Pig’s diet. In other words, lack of nutrition or appetite is known to significantly affect their size, resulting in them being smaller than normal. On the other hand, too many treats might cause your guinea pig to become bloated and overweight, which is very unhealthy and deserves instant attention. So, learn before providing any food guinea pigs can eat and give them that.

#3 Medical Issue

What is extremely important is to check on any medical issue that is most likely to cause a sudden increase in the weight of a guinea pig. Respiratory infections, pregnancy, scurvy, diarrhea, or a tumor are some health problems that might affect your pet piggy’s growth. 

#4 Genetics

At last, while everything might seem alright, your guinea pig is still consistently smaller or bigger than what is naturally expected of them. It is nothing but genetics. Different breeds come in different sizes, and your guinea pig would most certainly reach it accordingly at the right time. 

When Does a Guinea Pig Stop Growing?

The growth of these tiny rodents becomes naturally stunted after about 6 months of age. But, how big can guinea pigs get? Well, around 24 weeks, a guinea pig is considered an adult. They cease to grow after this age, and their total size is likely to be judged quite accurately at 14-16 weeks. By this time, they would be 20 to 30 cm (8 to 10 inches) long and weigh around 700 to 1200 grams. However, they could gain only a few grams of weight. The extra layers of fat packed on after this is often misunderstood as size enlargement. 

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What is the Perfect Cage Size for Guinea Pig? 

When most of you think of your perfect home, you certainly imagine enough space to rest, relax, eat, sleep and have a room for some fun activities. This is even more true when it comes to pets residing in captivity. Guinea pigs require ample space to wander constantly since they stay active for around 20 hours a day and sleep only in short bursts.

Both the RSPCA in the UK and The Humane Society of the US have certified that 7.5 square feet is the minimum size required for two guinea pigs. A scientifically proven, large cage for Guinea Pigs equates to 4 x 2 feet, which is the exact size of a Midwest habitat cage. The perfect size for two guinea pigs is 10.5 square feet of area, including the extra space for necessary items like food bowls, hay, hiding places, and a couple of fun interactive things for them to play with. 


Well, this is all about Guinea Pigs. If you are planning on getting or adopting a guinea pig, there are numerous important factors besides the basic ones to acknowledge. Keeping them as pets requires sufficient arrangements and education because they are unlike regular pets. Guinea pigs are fragile as a juvenile or an adult. Thus, taking care of guinea pigs becomes a prerequisite for life, as caring and loving individuals.