Medical Monday: Weekly Weigh In!

Weighing your guinea pigs regularly is probably one of the most important things you can do for them, a guinea pig who is rapidly losing weight is an ill guinea pig. Guinea pigs are prey animals so they’re really good at hiding any visual signs of illnesses, they don’t want to appear to be weak because in the wild that would make them vulnerable.

A fully grown guinea pig can weigh anywhere from 700g to 1300g. A guinea pigs’ weight depends on so many different factors, like their gender, start in life, diet, companion relationships etc, that it’s really hard to pinpoint an ideal weight for all guinea pigs. Generally, females will weigh less than males but that isn’t always the case! Our very own Summer is 300g heavier than her male friend, for example, if we judged them the same then we would think that Hilton could be ill or that Summer was too heavy.

A good method of monitoring a pigs’ general size, is to give them a good old fashioned cuddle! Some piggies will slim down without actually losing any weight in grams, this is especially common when entering their senior years. You should run your hands down both sides of your pig, starting from their ears and going all the way down to their rump. A well-shaped piggy will have a layer of fat but you’ll still be able to feel their ribs and spine without too much effort – if you can feel bones without trying then they’re too light if you can’t find the bones easily then they’re probably overweight for their individual frame.

Our recommendation is to also weigh each of your guinea pigs once every week or two weeks to get a ‘baseline’ weight, that way you can keep track of each piggy’s average weight and easily spot any abnormalities. This avoids the weight comparison between your pigs and treats each guinea pig as the unique piggy they are 😀

Weighing your guinea pigs doesn’t need to be a fancy affair, most kitchens already have a pair of suitable scales. All you need is a nice sized bowl to sit your piggy in and an accurate digital scale which can weigh in grams, we always suggest you weigh in grams as it’s a much smaller measurement than pounds or ounces so you can see a decrease or gain clearly. 

You can use a notebook or a spreadsheet, but whichever method you choose – make sure you keep a record of every weight. This is so important because without a history of weights and dates you’ll have no way of knowing how much weight has been lost if you do think your piggy is ill! We have created a handy weight chart and a fancy graph version that you’re welcome to use:

NEPB – Weight Chart NEPB – Weight Graph


A guinea pig can lose as much as 40g by just having a wee so you shouldn’t worry as soon as you notice a weight loss but anything around or over 50-100g is a cause for concern and you should begin to check for issues and consider a vet visit. If you suspect that your guinea pig is ill then you should weigh them every day, at the same time of day, this helps monitor their immediate situation and can also help the vet know how serious the problem is. Low weights can be a sign of conditions such as kidney or heart issues so if you’re ever worried, please take your guinea pig to a vet straight away.

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