Guinea pig: lifespan, size, diet and care
Guinea pigs can’t make their own vitamin C: give them peppers, kale or parsley every day.
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How big it is
An adult is up to 25.4 cm (10 in) long.
Zoomed ×4: here you see the man up to 47.5 cm (19 in) off the ground
Before it arrives
- At least two guinea pigs: they shouldn't live alone
- A big space where they can run and stand up on their back legs, plus an exercise area
- One more hideout than the number of guinea pigs, and a few tunnels
- Bedding: dust-free shavings and hay; never pine, straw or cotton wool
- Plenty of grass hay, guinea pig pellets and vegetables rich in vitamin C
- Untreated wood to chew: their teeth never stop growing
- A spot at 17–20 °C (63–68 °F), away from radiators, sun and drafts, and from dogs, cats and ferrets
Its home: temperature and light
- The room
- 17–20 °C (63–68 °F)
What it eats and how often
hay, fresh pellets and vegetables every day
- Juveniles, up to 6 months (alfalfa hay and pellets for young guinea pigs): every day
- Adults: every day
Grass hay always available: it's the biggest part of the diet. Every day, fresh vegetables and a new portion of guinea pig pellets, as the bag says (don't just top up the bowl: vitamin C breaks down). Vitamin C: at least 10 mg per kg of body weight a day, 30 mg if pregnant.
Vaccines and checkups
None: guinea pigs don't need vaccines.
A checkup at the vet every year. With a vet who knows guinea pigs.
The care calendar
What to do, from the most frequent to the least.
- every dayHay, veg and pelletsHay at all times, fresh veg rich in vitamin C and a new portion of pellets: don't just top up the old ones.
- every dayCheck its bottomIt should be clean and dry, with no droppings stuck to it. In summer, twice a day: dirt attracts flies.
- every weekTeeth and nailsCheck the front teeth and the nails: they grow fast.
- every weekBrush its coatOnce a week; every day if it has long hair.
- every weekDeep clean the cageSpot-clean every day.
- every yearYearly check-up at the vetWith a vet who knows guinea pigs.
Call the vet right away if…
If you see one of these signs, call your vet now: don’t wait for it to pass.
- Eats or drinks less, or passes fewer droppings or none
- Struggles to breathe
- Drools, its front teeth look too long, or its jaw is swollen
- Diarrhea, or soft droppings stuck around its bottom
- Loses a lot of weight in a short time
Frequently asked questions
How long does a guinea pig live?
Usually 5–8 years.
How big is a guinea pig?
An adult is up to 25.4 cm (10 in) long.
How much does a guinea pig weigh?
An adult usually weighs 700 g (1.5 lb) to 1.6 kg (3.5 lb).
What does a guinea pig eat, and how often?
Hay, fresh pellets and vegetables every day. Grass hay always available: it's the biggest part of the diet. Every day, fresh vegetables and a new portion of guinea pig pellets, as the bag says (don't just top up the bowl: vitamin C breaks down). Vitamin C: at least 10 mg per kg of body weight a day, 30 mg if pregnant. Juveniles, up to 6 months (alfalfa hay and pellets for young guinea pigs): every day; adults: every day.
Does a guinea pig need vaccines?
None: guinea pigs don't need vaccines.
When should a guinea pig see a vet right away?
Right away if you see one of these signs: eats or drinks less, or passes fewer droppings or none; struggles to breathe; drools, its front teeth look too long, or its jaw is swollen. The others are above, in “Call the vet right away if…”.
How old is a guinea pig in human years?
There’s no serious human-years chart for a guinea pig: the ones online don’t cite sources. What counts is where it is in its life: its senior years start at about 3.8 to 6 years old.
Tools for your guinea pig
Always ask your vet: this site helps you understand, it doesn’t replace a checkup.
Sources
- RSPCA, Guinea pig health (checked on September 30, 2026)
- PDSA, Guinea pig health (checked on September 30, 2026)
- Merck Veterinary Manual, Description and Physical Characteristics of Guinea Pigs (checked on September 30, 2026)
- Merck Veterinary Manual, Overview of Rodents (table: Biological Data of Pet Rodents) (checked on October 13, 2026)
- Merck Veterinary Manual, Housing and Nutrition of Guinea Pigs (checked on October 13, 2026)
- RSPCA, Guinea pig diet (checked on October 13, 2026)
- Merck Veterinary Manual, Routine Care of Guinea Pigs (checked on October 13, 2026)
- Merck Veterinary Manual, Nutritional Problems of Guinea Pigs (checked on October 13, 2026)
- RSPCA, Guinea pig environment (checked on October 13, 2026)
- Animal Diversity Web, Cavia porcellus (checked on October 13, 2026)