Guinea pigs size

The size of a guinea pig depends not only on the age, breed and sex of the pet. The growth and weight of an full grown guinea pigs also depends on the housing conditions. Lack of nutrients in the diet leads to growth retardation. Overfeeding and being overweight also cause serious damage to the body.


To what size can a pet grow at home?

Guinea pig – description of the animal

The guinea pig is native to South America. The tribes that lived there in the 5th millennium BC. Indians were engaged in breeding these cute rodents. They domesticated the animals so they could eat their meat. They also sacrificed the animals to the gods. After
Columbus’s discovery of America, the animals made their way to the European continent.

The guinea pig does not live in water and does not like to swim, although if necessary can swim across a small stream. It got its name because it was brought by ship by sea, and in some ways resembles a piglet.

Nowadays, South Americans also use ginny pigs as a source of dietary meat. In taste and nutritional value it’s similar to chicken.

Guinea pigs are rodents that belong to the mumps family. In their natural habitat, they can be found in mountainous areas, forests and dense vegetation woods and dense edges.

They form groups of 10 to 14 and settle wherever there is plenty of plant food.

Guinea pigs size

Guinea pigs size

Size and weight of rodents

The guinea pig grows to a size of about 24-35 cm in length. The height at the withers is 5-7 cm. Dimensions largely depend on the breed and sex females are slightly smaller than males.

The guinea pig weighs 700-1500 g. The size of the guinea pig ranges from 22-35 cm, and the body weight is 1-1.8 kg. Animals are most actively developing until the age of one year, but continue to grow for several more months.

Size guinea pig reaches its maximum when it is 1.5 years old. Then its growth stops.


Guinea pig – appearance

Those who have carefully studied the description of the guinea pig have noticed how unique its body structure is. It is nothing like rabbits or chinchillas, and even more so has significant external differences from rats and hamsters.

What does a guinea pig look like

Guinea pig appearance:

  • The body is cylindrical in shape, grouped, with well-developed muscle mass;
  • the head is quite large;
  • wide, blunt snout;
  • the eyes are rounded, beaded;
  • ears of medium size, flexible, with wavy tips;
  • the neck is so short that it is almost invisible;
  • limbs of small length;
  • four fingers on the front paws, three toes on the hind legs;
  • without tail.

Wool can vary in length, texture, and color depending on the guinea pig breed. The coat can be long or short. There are also bald varieties.

Guinea pig size at birth

Guinea pig size at birth reaches from 5 to 10 cm. The weight of guinea pigs also depends on the breed, the smallest weigh 45-50 grams, and in larger breeds up to 100-120 grams.

The size of baby guinea pigs depends on how many of them are born in the litter. The size of newborns depends on how many female guinea pigs there are. If the female guinea pigs has many cubs, they will be smaller. The very first are born more than the next.

Guinea pigs size

Baby guinea pigs

Of course, the size of guinea pig pups depends on how the pregnancy of the female goes. A healthy guinea pig can have three large babies that weigh up to 100-120 grams.

Baby guinea pigs are considered newborn until they are seven days old, and they do not notice any growth during this period.

Guinea pig size is up to a year

Baby guinea pig grow dramatically in size from 8 to 30 days of age. They gain 4-5 grams daily in weight. By one month, they reach a size of 14-19 cm with a weight of 200-400 grams.

At three months, the babies grow another 5-6 cm in height and ten times their birth weight.

Does guinea pigs eat bananas, read our article.

6-month-old guinea pigs

You can tell the sex of a pups by its size at 6 months of age. If bigger and fatter, it will be a boy, and if small, it will be a girl guinea pig. At this age the cubs grow to a size of 20-25 cm, although growth and weight stops as fast as during the first month.

Also, there is no active growth of guinea pigs before one year of age. During this period, pet rodents already have the ability to reproduce sexually. Their body is already fully physically ready to continue to give offspring.

But you should not rush with the breeding of pets, and it is better to wait until 10-12 months, as the young in this period, the body is fully strengthened. From six months to one year, guinea pigs have a significantly reduced production of growth hormone.

full grown guinea pig


Stopping growth

Guinea pigs stop growing by the age of a year and a half and are considered fully mature and reach their maximum size. An adult guinea pig over 15 months of age no longer adds weight. 

Full grown guinea pigs

Adult guinea pigs do not change in weight with adequate nutrition. Male guinea pigs achieve a healthy weight of 1 to 1.8 kg, and female guinea pigs from 0.7 to 1 kg. If these values in body weight increase, the diet of animals should be reviewed. Rodents should not be fattened, it is dangerous for their active lifestyle.

At 4 years of age, domestic rodents begin to age. Pet begin to move less, reproductive function disappears, and metabolism changes.

In old age, animals often lose weight. This is a natural phenomenon. If an animal has lost weight too quickly, you should definitely sound the alarm.

How long do guinea pigs live?

With the best housing, the average life expectancy of pets in the home is 6-8 years. Long-haired guinea pigs have a shorter lifespan than short-haired guinea pigs.

The largest breeds of guinea pigs

The largest guinea pigs of the kui breed are the largest in size. They used to be bred as pets.

Nowadays, giant guinea pigs are kept as pets. The size of the guinea pig breed kui can reach up to 50 cm, and the average weight of a guinea pig is 2 kg. They reach these proportions by the age of six months.

Keeping these animals is quite problematic. They have a shaky nervous system and react acutely to stress. In addition, they are lazy and sedentary. Kui have poor health and live only 3-4 years.

kui guinea pig

From this we can conclude that you should not overfeed your animals, because it leads to private health problems.

Guinea Pig Size Chart

Guinea pig’s size

To make it easier to navigate the table below is a table of which guinea pig are life-sized:


Body length

about weeks

8-9,5 cm

2 weeks

10-12 cm
3 weeks

14-15 cm

5 weeks

16-20 cm
7 weeks

21-23 cm

1 year

24-25 cm

15 months

27-35 cm

Average guinea pig weight

In this table you will learn in detail about the weight of guinea pig’s by month:



Average guinea pig weight


about weeks 50-120
0,5 months 90-180
1 months 145-240
1,5 months 200-300
2 months 350-400
3 months 500-700
6 months 650-800
1 year 800-1000
15 months 900-1500

At what age to buy a guinea pig?

You should not buy a very small guinea pig. Baby guinea pig’s are like children, they can’t be without their mother, and it will be very stressful for them. Only at 5-6 weeks, domestic rodents become independent, their body is fully strengthened, so it is better to take it from this age.

Guinea pig 3.5 years old

Pigs older than 1.2 months and up to 3.5 years old will get used to their new home environment. Older than 3.5 years it is better not to buy guinea pigs, they begin to age. Neither the guinea pig nor you will have it easy.

Most guinea pigs in the pet store are not in the best conditions, even those that are old. Then of course in this case it should not be a question of his age better to buy and let him finish the last years of his life fed, groomed and warm.

Body length as an indicator of age

Salespeople at the pet store may often not know what the age of the guinea pig is. This requires knowing that the size guinea pig will give you an indication of what age they are. With this knowledge, you can avoid the unwanted purchase of a young guinea pig.

How to Measure a Guinea Pig

Put the guinea pig on a flat surface and place a ruler next to it parallel to its body. Measure the guinea pig from its nose to its end “butt”. The guinea pig will of course throw up and prevent you from getting exact measurements, but an approximate measurement will suffice.

How to choose a guinea pig

It is better to buy a guinea pig from a breeder with a good reputation. People who professionally engaged in breeding rodents, value their name and will not deceive buyers.

Breeds of guinea pigs

The first thing to decide on the choice of breed. There are with short hair, with long hair and hairless guinea pig. The choice of guinea pig breeds depends on size.

The following breeds of pet guinea pigs are larger in size:

  • Abyssinian;
  • Alpaca ;
  • Coronet ;
  • English Self ;
  • Rex guinea pig;
  • Teddy;
  • Kui;
  • Himalayan;
  • Peruvian
  • American guinea pigs. 

These animals often reach a weight of more than 1-1.5 kg.

Rex guinea pig

The same breed rex is no less than other breeds, as well as the American guinea pig. During the childhood period, rapid growth is observed. At birth, the guinea pig usually weighs between 50-140 g. This parameter is determined by the year of the mother, the conditions in which the pregnancy took place, and the number of newborn individuals in the litter. The first rodents are large in size.

Two weeks after birth, the weight of the rodent should double. At 5 weeks, the guinea pig should be 19 cm tall according to the standards. It is at this time you can buy a rodent. Animals can already safely be weaned, physically they are ready for this event.

Rex guinea pig

Guinea pig size

At 3 months of age, you can distinguish between male guinea pigs and female guinea pig by size. The weight of the rodents is already 10 times that of a newborn guinea pig. The body is considered fully formed after six months. Then mating can begin. Breed’s maximum length 35 cm.

How much do guinea pigs cost?

Guinea pigs for sale

A guinea pig costs $10 to $40 at a pet store, and the American cavy breeders association sells from $25 to $50.
To choose the right pet, you should look beyond looks.

The main thing is buy a healthy animal. In what cases you should refuse to buy:

  • If the guinea pig has a runny nose;
  • If the guinea pig has red, swollen or watery eyes;
  • the animal is lethargic;
  • Its coat looks unkempt and disheveled;
  • wet or muddy under the tail;
  • the guinea pig is breathing heavily, wheezing, sneezing;
  • There are scratches or gaps on the body.

Such symptoms should alert the buyer. They are signs of poor ill health.


Guinea pig can be kept in a cage, hut or aviary. The basic requirements for a guinea pig dwelling are:

  • availability of space,
  • good maintenance of the structure,
  • good ventilation, ease of cleaning.

An aquarium or plastic cage is not suitable.

The cage should be bought so that when the guinea pig are fully grown there is enough space to accommodate them. Care should be taken from the start before buying a house for guinea pig, so that you don’t have to buy a second one later.




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