How do I take care of guinea pigs?

At a glance

What you're signing up for

Two guinea pigs. Not one. That is the first honest sentence of guinea pig ownership: they get lonely and should not be kept alone. The RSPCA says they're happiest in pairs; their wild relatives live in family groups of 5-10; and Switzerland's animal-welfare law makes keeping a single guinea pig literally illegal. Plan for a same-sex pair or a neutered male with a female, and budget everything below for two.

The second surprise is the calendar. Guinea pigs live 5-7 years, sometimes past 8 — far longer than the hamsters and gerbils they're shelved next to, and longer than most buyers budget for. A guinea pig bought for a nine-year-old is still there when that child starts high school.

The daily reality is pleasant but real: fresh vegetables prepped twice a day (vitamin C is a dietary requirement, not a nice-to-have), hay always topped up, spot-cleaning, floor time, and a health check on animals that are professionals at looking fine. Guinea pigs are prey animals; they hide illness until it's serious, which is why the cheapest piece of medical equipment you'll own is a kitchen scale — a weekly weigh-in catches weight loss weeks before anything else does. Compared with a rabbit, though, this is the gentler deal: no 4-hour exercise quota, no bunny-proofed house, rare biting, and a chatty animal that whistles at the fridge. For most first-time families, guinea pigs are the better fit.

Housing

Start with the Humane Society of the United States' uncomfortable truth: "most cages marketed for guinea pigs are way too small." Guinea pigs are among the largest rodents kept as pets, and stores sell them hamster-scale housing. The HSUS minimums: 7.5 sq ft (about 30" x 36") for one or two pigs, with 10.5 sq ft (30" x 50") preferred for a pair; 10.5 minimum and 13 sq ft preferred for three; 13 minimum for four. The cheap way to hit those numbers is a C&C cage — storage-cube grids with a coroplast (corrugated plastic) base — rather than anything in the small-animal aisle.

Some setups are simply out, per HSUS: no plastic tubs, no glass aquariums (ammonia builds up in the poor ventilation), and no wire floors, which cause bumblefoot — infected pressure sores. Sides should be at least 12 inches high, over 2-3 inches of paper-based bedding. Never use cedar or pine shavings; their aromatic compounds are harmful.

Keep them indoors. HSUS discourages outdoor hutches — they rob pigs of regular family interaction and add predators and temperature risk. The temperature band is narrow: 65-75°F with humidity under 50%, and anything above about 85°F can cause heatstroke. A summer garage or a sunny window can be lethal. They handle cold poorly too; indoors is the US welfare default.

Add one hide per pig — prey animals need cover, and it prevents squabbles — plus daily supervised floor time in a pig-proofed area. They don't climb or jump like rabbits, so a simple ground-level pen works. Skip exercise wheels and balls entirely; they're unsafe for their spines.

Feeding

The template is hay first, vegetables daily, plain pellets in small measured amounts. Unlimited good-quality grass hay should make up the majority of the diet and be available at all times — it keeps the gut moving and wears down teeth that grow for life. On top of that: a fresh daily portion of plain grass-based pellets and about a cup of fresh vegetables a day, with fresh grass when you can get it.

The part that makes them unique among common pets: like humans, they cannot make their own vitamin C — they lack the enzyme and can only store it briefly — so it must arrive in the diet every day, or they develop scurvy within weeks. How much? Sources genuinely range: Merck's baseline works out to roughly 10-25 mg per day for a typical adult (10 mg/kg/day, 30 mg/kg when pregnant), while the exotic-vet practice Arizona Exotics recommends about 90 mg a day for adults and 150+ mg when ill. You don't have to arbitrate: daily C-rich vegetables — bell peppers are the star — plus a fresh, guinea-pig-specific fortified pellet or a C tablet covers every recommendation. Two traps to avoid: rabbit pellets (no added vitamin C) and vitamin-C water drops — pigs would need to drink unrealistic volumes, the taste suppresses drinking, and the vitamin degrades in light. Also skip muesli-style mixes: pigs eat the sweet, starchy bits and leave the fiber, the same selective feeding a two-year University of Edinburgh study tied to life-threatening dental and digestive disease.

Good daily vegetables from the Pasadena Humane safe list: bell peppers of every color, romaine and green or red leaf lettuce, cilantro, parsley, cucumber, zucchini, endive, green beans, snap peas. Fruit — apple, berries, melon — is an occasional treat only.

Never feed: avocado (persin damages the heart); chocolate or anything caffeinated; onion, garlic, leek, or chives (hemolytic anemia); rhubarb; raw potato; fruit seeds and pits (cyanide traces); hot peppers; iceberg lettuce; nuts and peanut butter; dairy, meat, or eggs (they cannot digest animal protein); bread, pasta, or processed food; and cabbage, cauliflower, and brussels sprouts, which Pasadena Humane lists as unsafe gas-formers.

Health

Scurvy is the signature preventable guinea pig disease. Signs per Merck: rough coat, lameness, weight loss, diarrhea, swollen painful joints, bleeding under the skin or from the gums, reluctance to move, sudden illness — and death if untreated. Any vitamin-C-deficient diet produces it within weeks.

Dental disease is the hay-shortage disease. Guinea pig teeth are open-rooted and grow throughout life; only constant chewing of fibrous hay wears them down. Low-fiber diets cause malocclusion and root elongation. Watch for drooling ("slobbers") and dropped food.

Bumblefoot (pododermatitis) is infected pressure sores from wire floors, wet bedding, or obesity. It's why wire floors are banned from any decent setup.

Also on the common list from VCA: pneumonia and respiratory infections, GI stasis, bladder stones and cystitis, abscesses, lice and mange mites (intense itching), ringworm, barbering (fur-chewing, often stress-linked), ovarian cysts in older unspayed females, and heatstroke above about 85°F.

The thread running through all of it: guinea pigs hide illness. VCA is explicit that symptoms may not appear until conditions are serious. Your early-warning system is boring and cheap — the weekly weigh-in, plus daily attention to appetite and droppings. Quiet red flags: eating or pooping less, weight down on the scale, hunched posture, crusty eyes, puffed-up coat, lethargy, not coming out for vegetables. A pig that skips the wheeking when the fridge opens is telling you something.

Go to a vet today if: your guinea pig hasn't eaten for 12-24 hours (gut shutdown kills fast, as in rabbits); it is lame, reluctant to move, or bleeding from the gums; it is drooling or dropping food; it shows labored breathing; or it is limp in heat above 85°F. Use an exotic-savvy vet — ordinary clinics often won't see guinea pigs, and penicillin-class antibiotics, safe for dogs, are dangerous for pigs.

Two reproductive facts worth knowing even if you never breed. First, pet stores frequently missex pigs, so "two females" sometimes becomes a litter; males must be separated from females by 3-4 weeks of age. Second, a female bred for the first time after about 8 months risks fatal delivery complications because her pubic symphysis stiffens. Routine spay/neuter is less universal than in rabbits — anesthesia risk is higher, so vets weigh it case by case, most often neutering a male to allow a mixed-sex pair.

What it really costs

The animal is the cheapest line on the invoice: $30-$65 from a shelter or rescue (often with supplies thrown in), about $50 at a pet store, $100-$1,000+ from specialty breeders. Then the real spending starts — a proper cage runs into the hundreds of dollars, plus an initial wellness exam at $100+, bowls, a bottle, a hide per pig, a hay rack, nail clippers ($4-$14), and bedding or fleece liners. This is the classic cheap-animal, not-cheap-setup problem, doubled because you're buying for a pair.

Monthly, per Chewy's expert-reviewed guide: pellets $30-$50, vegetables $20-$50, timothy hay $40-$60, bedding around $30. Chewy's all-in annual totals: food $1,080-$1,920, vitamin C supplements about $120, cleaning and upkeep about $360, and vet care $500-$3,000 — $2,060-$5,400 a year. Those food figures assume premium supplies for a pair; budget owners buying hay in bulk spend meaningfully less. The honest headline: a healthy pair plausibly costs $600-$1,200+ a year, healthy pigs typically run $500-$600 a year in vet care (Dr. Steinagel's figure), and chronic disease — dental, stones, cysts — can reach $1,500-$3,000 a year at exotic-vet prices. Budget for the exotic vet before you fall for the $30 adoption fee.

Daily and weekly routine

Daily - Morning and evening feedings: top up unlimited hay, fresh water, measured pellets - About a cup of fresh vegetables, always including a vitamin C source such as bell pepper - Spot-clean wet bedding and droppings - Health glance: both pigs eating, moving, wheeking; eyes and coat normal - Floor time in a pig-proofed area

Weekly - Weigh each pig and log it — the single best early-illness detector - Full bedding change and cage wipe-down - Check nails, teeth, feet (bumblefoot), and skin; refresh enrichment

Monthly - Deep-clean the cage, hides, and bottles; wash fleece thoroughly - Nail trim if needed - Check pellet freshness — vitamin C degrades — and restock hay

Common mistakes

1. Buying the pet-store "guinea pig cage." Almost all are under the 7.5 sq ft minimum. Build or buy to 10.5 sq ft for a pair; C&C cages do it cheaply.
2. Keeping a single guinea pig. Against RSPCA and Merck guidance, and illegal in Switzerland for a reason. Get a pair from the start.
3. Having no vitamin C plan. Rabbit pellets, stale pellets, or water drops all fail. Daily bell pepper plus fresh guinea-pig-specific pellets works.
4. Feeding muesli mixes and sugary treats. Selective feeding leaves the fiber behind; plain pellets and unlimited hay instead.
5. Cedar or pine shavings, wire floors, or aquariums. Respiratory harm, bumblefoot, ammonia buildup. Paper bedding in a well-ventilated cage.
6. Trusting the store's sexing. Missexed "same-sex" pairs produce accidental litters, and late first pregnancies can be fatal. Have a vet confirm.
7. Outdoor hutches and garages. Isolation plus a lethal heat ceiling of about 85°F. Guinea pigs are indoor pets in the US.
8. Skipping weigh-ins and annual exams. Prey animals hide illness; the scale and an exotic vet find it while it's still fixable.

Is this pet right for you?

A good fit if... - You want a genuinely beginner-friendly small pet that's awake when your family is - You can house a pair in 10.5 sq ft indoors, at 65-75°F - Someone will prep fresh vegetables twice daily for 5-7+ years - You want an interactive, vocal animal for a household with supervised kids - You can afford exotic-vet care, not just the $30 adoption fee

Think twice if... - You want one low-maintenance animal in a small cage — that setup fails them twice - The plan involves an outdoor hutch, a garage, or a room without climate control - Daily fresh-food prep will quietly become nobody's job - Household allergies to hay or dander are untested - You expected hamster-scale costs and lifespan; this is a multi-year, four-figure commitment

Worth knowing

They get scurvy, like sailors. Guinea pigs share our missing enzyme and cannot make vitamin C. No dietary C means scurvy within weeks — the reason bell pepper is a staple, not a treat.

One guinea pig is illegal in Switzerland. Swiss animal-welfare law recognizes them as social animals and bans keeping a single pig — the tidiest one-line argument for a pair.

Pups are born ready to run. After a marathon 59-73 day pregnancy, pups arrive fully furred, eyes open, and nibble solid food within days.

The domestic guinea pig doesn't exist in the wild. A fully domesticated South American rodent, it has no wild form to return to.

Their teeth never stop growing. Lifelong open-rooted teeth are why unlimited hay is dental care, not just food.

Popcorning is real. The spontaneous vertical jump with a mid-air twist and a squeak is their signature happiness display; fright can occasionally trigger it, so read the context.

85°F can kill. Heatstroke starts above about 85°F. The danger zones are where people put cages: garages, porches, sunny windows.

They're built for a crowd. Wild-type relatives live in family groups of 5-10. A solitary pig in a small cage is as far from natural behavior as keeping them can get.

What you'll need

• C&C cage or equivalent, 10.5+ sq ft for a pair — pet-store cages are below welfare minimums
• coroplast base with 12"+ sides — contains bedding, no wire floors
• paper-based bedding or fleece liners — 2-3 inches deep; never cedar or pine (advice-only) (buy this where you already shop — we don't sell it, on purpose)
• unlimited grass/timothy hay — majority of diet, tooth wear, gut health (advice-only) (buy this where you already shop — we don't sell it, on purpose)
• plain guinea-pig-specific fortified pellets — daily measured portion with added vitamin C (advice-only) (buy this where you already shop — we don't sell it, on purpose)
• fresh vegetables incl. bell peppers — daily vitamin C source (advice-only) (buy this where you already shop — we don't sell it, on purpose)
• vitamin C tablets — backup C source; never water drops
• hide/shelter, one per pig — prey animals need cover; prevents squabbles
• hay rack — keeps hay clean and always available
• heavy ceramic food bowl — can't be tipped
• water bottle — fresh water always available
• kitchen scale — weekly weigh-ins are the cheapest early-illness detector
• ground-level playpen — daily supervised floor time; no wheels or exercise balls
• nail clippers — routine nail trims
• tunnels, paper bags, cardboard chews — enrichment for a burrowing, chewing animal
• hard-sided pet carrier — exotic-vet visits, including emergencies

Browse the store for the gear above.

Sources