Guinea Pigs

Most people search for guinea pig care when they’re weighing up a new pet, troubleshooting feeding, or trying to work out why a normally busy little animal has gone quiet. The stakes are real: small mistakes with heat, diet, or housing can turn into stress, illness, or a vet visit faster than you’d expect.

Guinea pigs (cavies) are sturdy, social herbivores with a few sharp requirements: constant fibre, daily vitamin C, steady temperatures, and a clean, roomy space that lets them move and hide. Get those right and they tend to settle into a calm, watchful rhythm at home.

Quick facts: guinea pigs at a glance

• Species: Domestic guinea pig (Cavia porcellus), originally from South America.
• Social needs: They do best with company of their own kind, housed safely together (same sex or desexed).¹
• Nutrition non‑negotiables: Unlimited grass hay and a reliable dietary source of vitamin C every day.^{1, 2, 3}
• Heat risk: Highly susceptible to heat stress; monitor closely as temperatures climb, especially above 30 °C.⁴

Introduction to guinea pigs

Guinea pigs, often called cavies, are small mammals that have lived alongside people for thousands of years. Their wild relatives come from South America, and domesticated guinea pigs were historically kept for food and other cultural uses before becoming familiar household pets in many countries.²

In the home, they are ground-dwellers: they don’t climb much, they prefer to travel along edges, and they need places to retreat when the world feels too open. When their environment is predictable and their diet is steady, their behaviour becomes easier to read—quiet grazing, short bursts of movement, and long pauses to rest and watch.⁵

History and domestication

Archaeological and historical evidence places guinea pig domestication in the Andean region of South America, thousands of years ago. From there, they spread internationally and became established as companion animals, as well as animals used in education and research settings.²

Modern pet guinea pigs are still shaped by those origins. They are built for foraging and steady digestion, not for rich foods or long periods without fibre. Their care makes more sense when you treat them as grazing animals in miniature, rather than “small rabbits” or “low-effort rodents”.^{1, 6}

Characteristics and physical features

Guinea pigs have a compact, rounded body, short legs, and a coat that varies widely in length and texture. Their feet are distinctive: four toes on the front feet and three on the back. They don’t have a functional tail, and they’re not built for climbing or jumping like some other small pets.⁶

Behaviourally, they are alert prey animals. Startle responses are normal—sudden grabbing, loud noise, or chasing hands in a cage can teach them to fear handling. Calm, predictable contact usually works better: slow hands, support under the chest and hindquarters, and short sessions that end before they struggle.¹

Housing and daily care

Space, ventilation, and layout

A good enclosure is wide, well ventilated, and set up like a small landscape: open areas for walking, plus covered spaces where they can disappear from view. Guinea pigs tend to move along edges and gather around the perimeter, so long, rectangular layouts often work better than tall, narrow cages.⁵

Minimum sizes vary by guideline, but “bigger than the pet shop cage” is a reliable rule of thumb. As a practical baseline, RSPCA Victoria lists a minimum of 2,500 cm² usable floor space for a pair (with additional space for more animals), and recommends keeping enclosures as large as possible.⁷

Bedding and cleaning

Use absorbent bedding that stays dry underfoot, and give them a clean, dry sleeping area at all times. Damp, dirty bedding increases the risk of skin issues and respiratory problems, and it also changes behaviour—animals become restless, avoid parts of the cage, and stop lying out comfortably.⁴

Animal Welfare Victoria advises removing soiled bedding and keeping hutches clean; they also note that poor hygiene contributes to respiratory infections, skin problems, and parasite issues.⁴

Temperature and heat safety

Guinea pigs handle heat badly. Aim for a stable, mild environment and avoid direct sun on hutches or indoor cages near windows. RSPCA Victoria notes an ideal ambient range of roughly 16–24 °C, and warns that heat stress can be fatal.⁷

Once the temperature goes above 30 °C, Animal Welfare Victoria recommends monitoring guinea pigs regularly and using cooling strategies (such as a frozen drink bottle or ice brick placed so the animal can choose to sit near it, not forced against it). Shade and airflow matter more than almost anything else on hot days.⁴

Diet and nutrition

The foundation: hay and fibre

Guinea pigs are herbivores designed for constant grazing. They need fresh grass hay available all the time to keep the gut moving and to support healthy tooth wear.^{1, 6}

Vitamin C: daily, reliable, non‑optional

Guinea pigs cannot make their own vitamin C, so they must get it from food every day. Without it, they can develop scurvy and other serious problems. Merck Veterinary Manual notes that deficiency signs can appear within about two weeks if vitamin C isn’t provided, and gives a maintenance requirement of about 10 mg/kg/day (higher in pregnancy).^{2, 3}

Fresh vegetables that are naturally high in vitamin C (such as capsicum and leafy greens) are usually the simplest, most dependable approach. Pellets formulated for guinea pigs can help, but vitamin C degrades over time with heat, light, and moisture—so check best-before dates and storage conditions, and don’t rely on old feed.^{1, 2, 3}

Pellets, veg, fruit, and treats

Offer high-quality guinea pig pellets in small amounts rather than as the main diet. RSPCA Australia suggests pellets can be offered in small quantities and should not form the bulk of feeding.¹

Fruit is best treated as an occasional food because of its sugar content. Choose simple, fresh options and keep portions small; it’s easy for a guinea pig’s diet to drift away from fibre and towards sweetness if treats become routine.¹

Avoid lawnmower clippings. RSPCA Australia advises never feeding lawnmower clippings, which can ferment quickly and cause digestive upset.¹

Common health issues to watch for

Guinea pigs often hide illness until they can’t. Subtle changes matter: less eating, quieter movement, fewer droppings, weight loss, or a different posture when resting. If something seems “off” for more than a few hours, it’s worth acting early.

• Heat stress: a warm body, lethargy, rapid breathing, refusal to eat, collapse. Heat can escalate fast and is an emergency.^{4, 7}
• Vitamin C deficiency (scurvy): rough coat, lameness, swollen joints, weakness, poor appetite; can be severe without prompt correction and veterinary care.^{2, 3}
• Respiratory disease risks: poor ventilation and dirty bedding increase risk; seek veterinary advice for sneezing, discharge, or laboured breathing.⁴
• Skin parasites and fungal issues: itch, hair loss, scurf, scabs; hygiene and early treatment help limit spread.⁴

Breeding and reproduction: a caution

Accidental pregnancies are common when young guinea pigs are sexed incorrectly or housed together too soon. They can become sexually mature early, so separating males and females before maturity is the safest default unless you have a deliberate, informed breeding plan and veterinary support.

Pregnancy and birth can carry real risks, particularly for older first-time mothers. Many veterinary references note that breeding a female for the first time after about 6 months can increase birthing difficulty, and careful advice from an experienced vet is important if breeding is being considered at all.⁸

Guinea pigs as pets: what suits them (and what doesn’t)

Guinea pigs fit well in homes that can provide routine—fresh hay, daily vegetables, frequent spot cleaning, and calm handling. They don’t need walks, but they do need steady attention to environment and diet.

• They suit: people who enjoy quiet daily care, have space for a large enclosure, and can keep them out of heat extremes.^{4, 7}
• They don’t suit: households wanting a “set and forget” pet, or anyone unable to manage temperature control in summer.

Final thoughts

A guinea pig’s needs are simple but strict: fibre all day, vitamin C every day, clean bedding, enough floor space to move, and protection from heat. When those basics are met, their behaviour becomes wonderfully consistent—soft footfalls along the edges of the enclosure, steady chewing, and the occasional sudden dash that ends as quickly as it began.^{1, 4, 7}

References

1. RSPCA Australia — How should I care for my guinea pig?
2. Merck Veterinary Manual — Guinea Pigs (rodents)
3. Merck Veterinary Manual (Pet Owner Version) — Nutritional Problems of Guinea Pigs
4. Animal Welfare Victoria — Caring for your pet guinea pig
5. Agriculture Victoria — Code of Practice: Housing and care of laboratory mice, rats, guinea pigs and rabbits (Part 3.2 Animal enclosures)
6. NSW Department of Education — Animals in Schools: Guinea pigs (environment)
7. RSPCA Victoria — Housing for guinea pigs
8. Alma Street Veterinary Hospital — Guinea pig care (including breeding notes)