How to Determine Gender on Guinea Pig?

How to Tell Your Guinea Pig Sex? 

It is quite simple, against information, we usually find! You can even tell the sex of a few days old little piggy. When the piglet reaches the age of about two weeks, sex determination shouldn’t cause any problems. You just need to know, what things you should pay attention to. 

Two Weeks Old Guinea Pig

In the pictures bellow reproductive organs of two weeks old piggies are described (of the girl and the boy).

“Hollows” of sex organs of a female guinea pig are in shape of letter “Y”.

In the drawing and picture of a boy, you can see a small ball (yes – it is an element which you are thinking of) from which a vertical line extends.

One Month Guinea Pig

There are not many differences between one month old pigs sex organs and two week old ones, although they are bigger.

The girl’s proportion of hollows is changing a bit – the vertical line of the letter “Y” is much shorter. Only diagonal lines are clearly visible.

The boy’s penis is much better visible.

Three-Months Old Guinea Pig

Reproductive organs of three months old individuals are already fully developed. 

There is no difference comparing to the one month old piggy. 

You can see well-developed testicles.

Growing Up

After The Birth

A piggy is born with fur and it is a size of a mandarin. The moment after it is licked by its motherlittle piggy starts to look around. A few hours after the birth, she starts going out of the house and touring the cage.
Little pigs have disproportionately big paws and head compared to the rest of their body. With time
however, body proportion will change to the benefit of the backside.

A Few First Days

Little pigs are very brave and curious about the world. After a few days they start eating solid food, although they still drink milk from their momfor anotherthreeweeks. Their walk is clumsy and sometimes they fall down. 

The First Month

About 3-4 week old pigs should stop drinking mother’s milk. They are already quite big. They reach the size of over half the length of the mother’s body.

They love to play and chase each other. They jump funny and they wave their little heads. Males start to show an interest in females at the age of three weeks, although the females don’t want to play this type of games.

When a pig reaches the age of one month, it is a perfect moment to give it away to new owner, if we don’t want to keep it.

Between the First and The Third Month

Females achieve sexual maturity in the second month of their life, and males in the third month (officially). However, it can happen that our little piggy will be ready for breeding at the age of one month. That’s why you should separate males from mother and sisters, when males reach age of one month. Around the second month little pigs start calming down. They become less energetic. They sit and lie more than jump and run around the cage. If we want to sterilize males, we must wait until they reach the age of three months. Only then they are big enough and have well developed testicles. The vet won’t do this earlier anyway.

After the Third Month

Pigs have already reached sexual maturity; still grow, but very slowly. A pig can grow until it’s six months old. 

Basic Information

Scientific Classification

Kingdom: Animalia 
Phylum: Chordata 
Class: Mammalia
Order: Rodentia 
Suborder: Hystricomorpha
Family: Caviidae
Subfamily: Caviinae 
Genus: Cavia
Species: Cavia porcellus (guinea pig) 

Physiological Data

Body length: 23 – 35 cm (females are usually shorter), 
Weight: 700 – 1300 grams,
Life expectancy: 7 – 12 years,
Number of young per litter: 1 – 6 (usually 2 -3),
Body temperature: 37-39 Celsius degrees. 




Diarrhoea can be caused by: poisoning, bacterial infection, an inappropriate diet or when the diet has been changed too fast. Symptoms should not last longer than two days. You can try to help a pig by eliminating humid food from the diet for a few days. If symptoms don’t disappear, you should take your pig to a vet. If the pig has a fever too, don’t wait for the spontaneous improvement and go to the vet at once. The fever may be a symptom of a bacterial infection. In this case giving antibiotics is necessary. 


Its symptoms are red and stinking faeces. The pig needs to see a vet at once. A treatment is unfortunately long-term. It is based on giving paraffin oil and vitamins from the B-group to the pet. 

Excessive Fur Loss

It is caused by deficiency of fibre in a diet. Proper diet should eliminate symptoms. Your piggy should eat more food rich in fibre, such as hay, porridge oats or flax grains. 

Paralysis and Paresis

It can be caused by two factors: 
Virus. In addition to paresis there’s one more symptom – increase of body temperature. The pig should be taken to a vet immediately. There is no cure. It is necessary to put the guinea pig to sleep (euthanasia).
Vitamin A and B deficiency. It could be caused by a bad diet. In this case forecasts are much better. You can take your pet to a vet, although It will be sufficient to give your piggy food rich in A and B vitamins


Internal: tapeworms, nematodes, sheep liverfluke, flagellates, blepharismas etc. Symptoms of these parasites are: a change in stool color (on red) and weight loss. You should go to a vet, because only the doctor can establish proper therapy, which unfortunately is usually long-term.
External: chewing louse (look like white ascarids), lice, fleas. Symptoms: scratching, little cuts on the skin, reddening, fur loss. You shouldn’t give your pig any medicines on your own initiative
,although you can (in case of visible parasites) disinfect the pig using a preparation for fleas (purchased in a pharmacy or in a pet shop). After that don’t forget to wash your piggy and clean its cage. However don’t do anything on your own, if you see wounds on your pigs skin – the piggy has to be taken to a vet. 

Overgrowth of Teeth

It is most often caused by lack of hard food in the diet and teething rings. Overgrowth of teeth makes eating impossible, which can lead even to starvation. You should go to a vet who will trim teeth to the right size. 


Symptoms: runny nose and sneezing. Don’t give your guinea pig any medications on your own (except a food supplement with vitamin C). In such case, you should turn up the temperature in the room, in which the pig is. Cold should pass in a few days. If symptoms don’t stop or become more intense, you should go with your piggy to a vet. 


You should wash the woundwith hydrogen peroxide (don’t put nothing on it). If it doesn’t heal up, you should go to a vet. In case of cuts caused during claw trimming, you can use styptic powder – just put the pig’s paw into the container of powder. In case of more serious injury (heavy bleeding) a visit to a vet is necessary. 


It is caused by deficiency of vitamin C. Symptoms: swelling and sometimes bleeding gums. You can help your piggy very quickly – buy a food supplement with vitamin C in a pet shop. Your piggy should have a proper diet; it should contains lots of vitamin C. 

Pneumonia and Bronchitis

The symptoms are: increased thirst, poor appetite, heavy breathing, cough, sneezing, apathy, becoming dull and ruffled fur. It is difficult to determine whether it is pneumonia or bronchitis(pneumonia is more dangerous). We recommend to place the cage in a warm place. A help of a vet is necessary. 


Symptom: white spots on the eyeball. It is caused by a decrease in immunityA vet decides on a treatment – it is usually based on giving immune medications. 

Bone Fracture

It can happen, when the pig jumps into the cage from the owner’s hands (don’t let it do it!). In case of a fracture of the upper part of a pawimmobilized with a plaster isn’t possible, you can only hope, that the fracture will heal. When there’s a fracture of a lower part of the limb, a plaster cast is put on for a period of 8-10 days. 


Guinea Pig Breeding

We don’t recommend breeding guinea pigs. There are usually no problems during pregnancy and delivery, but bringing the younger generation up may be troublesome.

If you get a pig with a “surprise”….you must know some facts. Below we are presenting some information for future “parents”.

Basic information 

Pregnancy lasts 8-10 weeks and it is notvisible until the end of the fifth week. The pregnancy can be dangerous, if the pig is over a year old and it is its first pregnancy. Bones of a pelvis cannot spread enough – in this age they are firmly joined (if the piggy didn’t give a birth before). In this case you should go to a vet. Only a doctor can help. 

How to Tell Your Guinea Pig is Pregnant? 

If you have doubts, whether you are dealing with pregnancy, or perhaps your pig simply grew fat, at first you can check its belly. If it’s a fat issue, guinea pigs tummy will be soft in touch. If piggy is pregnant, its belly will seem to be “stuffed” and strained – you may feel like touching a balloon. Moreover during the pregnancy piggy’s sides also grow. During three last weeks you may see babies moving and even hear them. Of courseif you want to be sure, go to a vet to do the ultrasound scan.

Before the Birth 

Three to four weeks preceding the delivery, the expectant mother should be separated from other pigs. During last weeks you shouldn’t take the guinea pig out from the cage, in order not to harm babies. You can pat her. During pregnancy you should feed your piggy normally, although you can give her a little bit more food(even overfeed her). The piggy will demand more food. 

Birth and After The Birth 

Labor is very quick (usually a few minutes), mainly at night. The pig won’t show any signs of an upcoming delivery. There won’t be a big mess after, guinea pig as every rodent, eats the placenta. After the birth, little pigs should spend time only with their mother. They should not be taken out of the cage, till they are two weeks old. The mother can reject them, if someone else’s smell is on them. Smell of her owner on her children doesn’t disturb her very much. The pig looks after her children, she feeds and licks them. However, she isn’t too possessive and isn’t much upset, when one of her babies is missing for a moment.