Guinea pig body quirks - What is normal and what not?

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Staff member
Mar 10, 2009
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Coventry UK
Here are some body pecularities that can easily throw new owners!

It would be a very good habit if you gave your guinea pigs a once-over every week, at the same time as you are weighing them. That way, you can be sure to spot many problems early on. Guinea pigs can't come up and tell you what is wrong with them, so it is useful to know what is normal and what is not!

Guinea pigs have four toes on their front paws and three on their back feet. Occasionally, they can have an extra toe on their back feet. That is called polydactyly. Whether the extra toe needs to be removed, depends on how firmly it is attached to the foot. Please see a vet about the removal and don't do it at home.

Once the baby nails start growing out (which can happen any time between ca. 4-10 months old) guinea pigs need to have their nails cut regularly. You can prepare your youngsters by handling their feet from the beginning. Guide to Cutting Guinea Pig Nails

The soles of the feet should be smooth.

It is not uncommon for hard skin growths to develop on the sides of the front paw pads; they are called spurs. They should only be clipped off - but not too close to the skin where the spur is still live, could bleed and really cripple a piggy - if a spur is growing out sideaways and is at risk of catching and ripping. mostly spurs don't seem to bother the piggies and can be left. If necessary, ask a vet or nurse to remove bad spurs for you.

Soles can be overall pink when your piggy is feeling feeling warm, but any localised redness can be a sign for a beginning soreness/infection - the feet should not look both the same. Please see a vet if the soles of the feet are very red/have very red spots, are swollen or have open sores. Bumblefoot (pododermatitis) is more common in older guinea pigs with diminished mobility and a less effective blood circulation or in those that are kept on an unsuitable rough or uncleaned surface so bug can get in.

Bald patches and skin condition:
Most guinea pigs have symmetric bald patches behind their ears and no or very little hair on their ears.
They also lose their hair on the inside of their front legs from regularly washing themselves.

Any other bald patches are due to skin parasites like mites, fungal complaints or hormonal problems in some adult sows. Please have your piggies seen by a vet for a proper diagnosis! Do not home treat on spec with too low dosed shop products, or you can easily make the problem worse.
Guinea pigs do not go bald with old age and need to be seen by a vet if their hair is thinning out at any age.

A dull or fluffed up coat is a sign of pain and/or serious illness.
Scales, with or without hair attached to them, can indicate invisible mange mites or fungus.
Hair loss around the genitalia and the belly can be due to urine scald from an infection or because an older arthritic piggy is no longer able to clean itself.
Some guinea pigs can shed hair and will do so from time to time, but that should happen evenly all over the body and not result in bald patches.
Please investigate any increased itchiness for skin parasites or fungal. It can be just dry skin, but that is for a vet to decide.

Please see a vet if you find any lumps in or underneath the skin. The majority are benign fatty lumps or sebaceaous cysts, but it could be an abscess that needs antibiotics or another kind of cyst or tumor. Lumps become more common as your piggy ages; some piggies are more prone to getting a number of them. A vet needs to see and feel them to be able to decide whether they need treatment or can be safely left for observation.

Grease gland:
About 1 inch above the anus, guinea pigs have a grease gland on their back. It is especially active in male guinea pigs, but can do so in either gender and may need regular cleaning if there is a crusty build-up or the hair is very greasy.

Please check the privates regularly, but gently, and see a vet if there is swelling and heat, blood or smelly discharge of any sort.

A sow's genitalia can swell slightly when she comes into season, so try to spot what is normal for her and what is not! She usually has got a little plug in her bits when she is not in season. Sows come into season every 15-17 days.

Hay and bits can get caught in the penis sac and need to be removed carefully. Some boys may need daily checking, others get by with a weekly clean.
A guinea pig penis has two little hooks at the tip. Sometimes the tip looks curly; that is called a "cauliflower penis". A penis can be any colour from pink to purplish but it should never be blueish! In rare cases, a penis cannot be retracted; please see the vet about it.
Sometimes, smelly semen can harden around the penis. A semen rod needs to be removed carefully; it is very uncomfortable for the boar. The same "boar glue" (i.e. hardened semen) can also end up on other guinea pigs. If at all possible, carefully cut it off with scissors, unless it is too close to the skin.
Especially older boars can suffer from impaction when their muscles become too weak to push out the edible poos (caecotrophs) and need regular help with clearing out the anal sac.
Impaction - How To Help Your Guinea Pig.

Checking the gender:
If you are not sure about the sex of your piggy, look up this link: Sexing Guinea Pigs: How to Sex a Guinea Pig

Nipples and belly button:
Male and female guinea pigs both have two nipples, like humans; extra nipples are very rare. They also have a belly button, but it is not as noticeable in some guinea pigs as it is in others.
Please see a vet if a nipple is swollen, crusty or there is a lump underneath.

Eye colour:
Eyes come in all shades from dark to red to ruby to bright pink. Blue eyes are very rare. Guinea Lynx :: Eyes

There is a totally healthy special breed called pink eyed whites (PEW) that are NOT linked with albinism. Pink eyes are also common in golden and lilac guinea pigs.
True albinos are very rare; albinism is linked to a rare inherited recessive genetic condition with small eyes(microphthalmia)/blindness, deafness and dental problems; they are commonly referred to under the name of 'lethals' although the less affected can live happy normal lives for several years with the right kind of care. Both parents need to be carriers of the recessive roan/dalmation gene.

Healthy eyes should be bright and shiny and neither sunken nor bulging.

Eye cleaning fluid:
Guinea pigs do not blink and often sleep with their eyes open. They have a white milky fluid to clean the eyes.

See a vet promptly if your piggy has a runny, watery eye. It is usually either a sign of an irritation or an injury to the eye.
A blueish/whitish patch or film over the eye is a sign of an ulcerated eye injury and needs prompt vet treatment.

Also see a vet as soon as you notice crusty eyes or noses, epecially if the crusts are yellowish; they are symptom of a respiratory tract infection which can kill if not treated promptly. If in doubt, please see a vet; it may save your piggy's life!

Ears get generally floppier the bigger they grow, but the ear size can very quite a bit! Please check ears regularly for wax, ear mites and dirt.
See a vet promptly if you see a guinea pig shaking its head repeatedly or if it develops a head tilt; this is often the sign of an ear infection, which can kill or permanently damage if left untreated.

Guinea pigs regulate their body temperature via the blood flow through the ears; they do not sweat or pant. That is the reason why pale ears can look very pink at times!

The lips should be smooth.

If you notice sores or crusts on the lips, they are a sign of a fungal or bacterial lip infection (cheilitis), caused by feeding acid containing fruit and tomato too much and/or too often. Some guinea pigs are more sensitive to this. Please see a vet for treatment and stop feeding these foods.

The four front teeth (two at the top and two at the bottom) should be even and parallel. The bottom teeth always look longer than the top teeth. Healthy front teeth wear themselves down and sharpen themselves against each other and do NOT need regular clipping.

Guinea pigs have also got molar teeth at the back of the mouth, which should be ground down nice and even. Problems usually happen if that is not the case. Pre-molars can develop spurs which can grow painfully over the tongue or into the side of the mouth and prevent a piggy from chewing at all. If not treated properly, it can kill.

Beware of the vet who only checks and clips front teeth! He will just make the problem worse.
Plenty of hay is much more efficient in keeping the crucial back teeth ground down properly than gnawing toys.
The first signs of dental disease are often a slow weight loss, slowed chewing, picking up food and dropping it and salivating/wet chin.

Here is a link that lists early warning signs of illness. Please see a vet promptly!
Early Signs Of Illness
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