Why Is My Guinea Pig Biting and Scratching Himself?

My friend Josh has recently bought a guinea pig ( Paco) in one local pet shop ( although I recommend him to get a cavy from a rescue center, the pet shop was closer to his home). Yesterday morning he noticed that Paco was scratching and biting his own fur. Josh thought that Paco was grooming himself but the poor thing was doing the same for the whole day.

While occasional scratching is quite normal for guinea pigs, excessive scratching along with biting his own fur is the clear sign that something is wrong. That could be parasite infestation such as mites or lice. Another cause could be arthritis and the pain that it produces, especially in older guinea pigs.

The reason for guinea pigs to bite and scratch themselves may also be found in frequent bathing or you can misinterpret the whole situation and think that your pet is having some problem while he is just eating his own poop in order to keep flora in his gut healthy.

What Are The Most Common Causes For Excessive Scratching and Biting in Guinea Pigs?

Normal, occasional scratching in guinea pigs is nothing to worry about. Piggies might scratch a bit after a good nap or after they finish grooming.

Your cavy might be scratching because you have changed his bedding or hay contains some dust that irritates him.

But in all these cases, there is no biting, scratching is minimal and piggy doesn’t show any sign of pain ( grinding teeth or making excessive noise).

In case you notice excessive scratching in your guinea pig followed by biting himself, that’s totally different thing that requires your attention and action. What are the most common reasons?

Mange Mites in Guinea Pigs

Mange mites are super small parasites that are very common sources of itching in guinea pigs. Unfortunately, these parasites cannot be seen with the naked eye.

If left untreated, mange mites can be fatal for your piggy. However, they very easy to treat.

Mange mites can easily be spread from one guinea pig to another so if you have one piggy infected, you should treat all your guinea pigs just in case.

Many guinea pigs carry those parasites and have no symptoms nor problems. Especially those piggies that are sold in pet shops are at risk, as they are kept in large groups in small space and mites easily pass from one piggy to another.

Different kinds of stress or simply aging might be a trigger for symptoms to appear.

The first signs of this illness are hair loss, dandruff, and itching. This infection might occur anywhere although in a great number of cases neck and shoulders are the most common places.

As skin irritation progresses, excessive biting and scratching may lead to open wounds, that can be affected by bacteria which make the problem even worse.

Pain could be so intense that your pet refuse to eat or drink.

The best way to help your piggy is to take him to the vet. The most popular treatment against mites is Ivermectin. Your vet will prescribe the right dose and it’s very important to follow instructions.

This medication is not harmful if the dosage is correct but an overdose can jeopardize your furry friend’s well-being.

The treatment for mange mites is usually given topically, orally, or by injection. A single treatment is not enough, you will have to repeat the dose in 10 days but you will get all this information from the vet directly.

It’s said that Ivermectin is safe for pregnant piggies but not safe for very young cavies.

Don’t forget to treat all your piggies, no matter some of them haven’t experienced any problems so far.

Mange mites are problems that cannot be totally prevented. Simply some piggies carry those parasites and you cannot know that in advance. What you can do is to get a new guinea pig from a shelter instead of a pet shop.

Also when you bring home a new guinea pig, the wise decision would be to quarantine him for some time and watch if any sign of infestation will come up.

Some people believe that piggies can catch mites from hay or bedding but honestly, there is no scientific proof for that. Mites need a host, they cannot survive without it for more than 2-3 weeks so the chance your pet catch it from the hay you bought is really slim.

Lice in Guinea Pigs

Lice is also a parasite but a larger one and easily seen with the naked eye. Their goal is to attach to the skin as there the food is ( the blood). Their activity produces a big discomfort to guinea pigs so they need to scratch a lot.

Lice may appear anywhere on the piggy’s body but the face is their favorite spot since the hair is the shortest there.

If you suspect that your piggy has a lice infestation, seek vet help. This infestation is easy to treat but you need a vet to prescribe adequate treatment.

It’s not recommended to buy and over-a -counter medications in pet shops or drug stores. Medications that treat human lice are not appropriate as they are too strong.

Once your guinea pig receives adequate treatment, make sure you clean the cage and all the stuff from it, very thoroughly before your return your pet to his habitat. Change complete bedding and remove any food leftovers.

If your piggies have an isolated lifestyle, they don’t come into a contact with any other piggies, they have a slimmer chance to catch lice.

If you deal with someone else’s piggies, do wash your hands and change the clothes before handling your cavies. Although you cannot catch lice from guinea pigs, you still can transfer eggs from one guinea pig to another.

A lot of people claim that piggies can get this parasite infestation from hay or bedding. Although the parasites need a host, they can lay dormant for an extensive period of time before they find a suitable host.

It’s recommended you freeze any food or hay or bedding for 24 h, that way you will destroy lice and cut the possibility for your piggies to catch the disease.

Ringworm in Guinea Pigs

Fungal infection can cause very dry skin and your piggy will be scratching a lot. The most common symptoms are hair loss/bald patches and itchy skin. Bald patches usually appear first at the head area and then spread all over the body.

It is important to seek vet help as this disease may transmit from one piggy to another but also from a piggy to the humans. That’s why is crucial to be very careful if you deal with an infected animal as this highly contagious disease can easily jeopardize your whole family.

The vet will prescribe anti-fungal medications and baths. If left untreated for a longer period of time, excessive scratching will make wounds which may lead to bacterial infection. If that happens antibiotic treatment will be necessary.

Arthritis in Guinea Pigs

If you have an older guinea pig ( that can be 3 or 3,5 years old cavy but more often in cavies that are 5+ years old) and you have recently noticed that he is biting his back legs or hips so much that started to get bald patches from ripping his fur out then you should seek vet advice.

Most probably your piggy is in pain due to arthritis. Arthritis is a disease that affects older piggies. Once your piggy turns 3, you should include joints check during your weekly health check-up.

Joints should be flexible and moving them gently shouldn’t cause any pain to your pet. Also, you should look for swelling. If joints are swollen, that is a pretty clear sign of arthritis.

If you notice that that legs/joints are not so flexible and that your guinea pig is grinding his teeth you might ask your vet for advice on how to help your pet.

I have watched a very useful video of the LA guinea pig rescue center on how to check if your guinea pig might be suffering from arthritis and the recommended treatment for pain caused by arthritis was CBD gel pen ( pain relief gel cream for guinea pigs).

According to their experience, you should apply a pea-size amount of gel on the skin of your piggy’s both ears, twice a day. It should decrease the pain tremendously.

Arthritis in guinea pigs causes a lack of movement. The affected piggies sit more. Even when they are moving, they are hopping around or laming rather than regular walking as they are in pain.

Apart from changes in mobility, arthritis may cause changes in personality. It also can affect the ability to perform daily instinctual practices such as coprophagy when piggy eats his own feces in order to keep the flora of his gut healthy.

Until recently docile piggy now becomes very nippy and nervous, especially when you try to pick him up or pet his back end.

Pain and lack of mobility can prevent your piggy from eating his own poop ( he simply cannot curl up in order to reach it) which will result in dirty bottom. If left untreated, the skin on the bottom may become inflamed.

Very Dry Skin in Guinea Pigs. What Happens If I Bathe My Guinea Pig Too Often?

Guinea pigs are self-cleaning creatures and they do self-grooming very well. Usually, they don’t need a bath or they need it very occasionally, 2-3 times a year.

Butt bath is something different and can be performed more often especially if there is a need for it. If your piggy has diarrhea or dirty bottom ( due to arthritis for example) or scent glands become too smelly and greasy, then a butt bath is required.

I have read on one of the forums that a guinea pig owner who tries to take care of his piggy the best he can, bathe his pet once a month. It appears that his piggy bites his own fur and scratches a lot. He consulted a vet and it turns that piggy’s skin is very dry as a result of frequent bathing.

This guy was so surprised with the outcome as he was always using a special shampoo that is safe for guinea pigs. Too much bathing puts guinea pigs at risk of skin infections and colds.

Unless your guinea pig suffers from some parasite or fungal infestation so frequent bathing with adequate shampoos is prescribed by the vet, you should not bathe your pet too often.

Guinea pigs use the special solution they get from their eyes, to clean themselves. Healthy young or adult guinea pigs will successfully clean themselves and you don’t have to interfere.

In case you have an older guinea pig that is not so capable to groom himself as he used to be in the past you should bathe him but again, occasionally, not on regular basis.

Dry skin in healthy guinea pigs, that causes them to scratch a lot, doesn’t necessarily come from frequent bathing. It can come also from a very dry environment.

In that case, do think to purchase some air humidifier. Another reason could be that your piggies don’t drink enough water neither take sufficient amounts of it from the veggies.

Talk to your vet about their diet and what you can change. Maybe you are not changing their bedding as often as you should. Weekly bedding change is a must.

Is My Guinea Pig Grooming or Biting Himself?

Guinea pigs owners, especially inexperienced ones are not always sure if their piggies are grooming themselves or they have some kind of problems so they need to scratch or bite their own fur/skin.

How To Distinguish Between Grooming and Biting/Scratching?

The main difference is that grooming doesn’t leave any traces, spots, scratches, or bites. Grooming will not cause any bleeding or wounds.

Guinea pigs owners also can notice that their piggies are biting their own fur and then it seem like they are chewing something that they catch off the fur. Although it might look disturbing, could be quite a normal thing.

Guinea pigs eat their own poop. At least one type of it called Caecotrophs. They need it in order to keep their gut healthy. But they will not expel the feces first and then eat it so you can see clearly what’s going on.

You will hardly ever see this type of poop. It’s softer and smellier than the regular one. They will eat it directly from their anus. So they need to curl up and then to ingest it as soon as they know that it’s about to pop out.

So if you see that your piggy is chewing something after cleaning his behind, you will know what is it.


When guinea pigs scratch occasionally, there is nothing to worry about. But if that scratching becomes more frequent and aggressive, if biting occurs that you should consult a vet as something is wrong with your pet.

A variety of bacterial, fungal and parasite infection may cause rashes and inflamed skin in guinea pigs. Also, allergies or dry air in the room may lead to very dry skin that your piggy simply must scratch.

When the guinea pigs are biting themselves, that’s rather serious as most probably experience heavy pain. That can be either from arthritis or some other condition.

In any case, do observe your piggies regularly. Interact with them as much as you can. That way you will get to know their personalities and behavior. When you know them very well, you will easily notice any change that requires your special attention and help.

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