How to Care for a Guinea Pig: Complete Guide

Guinea pigs are among the most neglected small pets — sold in tiny pet store cages, fed seed mixes instead of hay, and kept alone despite being social animals. The three needs that pet stores never mention — vitamin C, companionship, and space — are the three that determine whether they thrive or slowly decline. The setup is more involved than the sticker price suggests.

This guide covers the enclosure, the diet, and the social requirements.

The Cage: Bigger Than the Pet Store Shows

• Minimum for two guinea pigs: 10.5 square feet, and more is better. The pet store single-pig cages are half the size they should be.
• Length beats height — guinea pigs are horizontal movers, and the floor space is the territory.
• Solid bottom, not wire — wire floors cause bumblefoot, a painful foot infection. Solid with paper-based bedding.
• Bedding: paper-based or aspen — never cedar or pine, the aromatic oils damage the respiratory system.
• Hiding spots — two per pig, so one cannot block access to both. Prey animals need retreat.
• Location: quiet room, away from direct sunlight and drafts, in a spot with household activity they can observe.

The Diet: Hay Is the Foundation

Timothy Hay: Unlimited

• Hay should be 80 percent of the diet — available at all times, in a rack or pile.
• It wears down the continuously growing teeth — without it, the molars overgrow and the guinea pig starves to death with a full bowl.
• Alfalfa hay for juveniles and pregnant sows — higher calcium for growth; timothy for adults.

Pellets: Fortified, Measured

• Timothy-based pellets — not seed mixes, which allow selective feeding and deficiency.
• One-eighth cup per pig per day — measured, not free-fed. Obesity is common in overfed guinea pigs.
• Vitamin C fortified — the pellet is the primary supplementation source.

Fresh Vegetables: The Vitamin C

• Guinea pigs cannot synthesize vitamin C — they need it daily, and deficiency produces scurvy: lethargy, joint pain, bleeding gums, and death.
• High-C vegetables: bell peppers (red and green), kale, parsley, broccoli, spinach in moderation.
• One cup of vegetables per pig per day — the C-rich ones count toward the total.
• Supplemental vitamin C — drops in water or directly, because the vitamin degrades in water within hours.

Fruit: Sparingly

• High sugar, occasional only — a small piece weekly, not daily.
• Never citrus — acidic, and not the right C source for them.

The Social Requirement

• Guinea pigs are social and should not live alone — a solitary pig is stressed, and stress shortens lifespan.
• Two females is the standard pairing — two males can work with enough space but often fight.
• Introductions take weeks — neutral territory, supervised meetings, and patience. Rushed introductions produce chronic fighting.
• Same-sex pairs or a neutered male with females — unneutered males with females produce constant litters.
• They communicate constantly — wheeking, purring, rumblestrating. A quiet guinea pig is often a sick one.

The loneliness of solitary guinea pigs is the most common welfare failure — the pair or group is not optional.

Health Monitoring

• Weight weekly — a sudden drop is often the first sign of illness, and guinea pigs hide symptoms until advanced.
• Scurvy signs: lethargy, rough coat, swollen joints, bleeding gums — vitamin C deficiency. Increase supplementation and vet visit.
• Respiratory infections: sneezing, discharge, labored breathing — common and serious. Vet visit immediately; they decline fast.
• Overgrown teeth: drooling, dropping food, weight loss — usually hay deficiency. Vet trimming; the hay prevents recurrence.
• Diarrhea: dangerous in small pets — dehydration kills quickly. Vet visit same day.
• Find an exotics vet before you need one — not every small-animal clinic treats guinea pigs.

Grooming and Handling

• Long-haired breeds need daily brushing — mats and hay tangles require cutting out, and the coats soil quickly.
• Short-haired breeds need weekly brushing.
• Nail trims monthly — the nails grow continuously and curl if untrimmed.
• Handling: support the chest and hindquarters — never squeeze, never pick up by the shoulders alone. Prey animals panic at improper restraint.
• Time on the floor — a guinea pig run or a safe room gives exercise that a cage cannot. Daily floor time is recommended.

Frequently Asked Questions

Can guinea pigs live alone?

No — they are social animals, and solitary guinea pigs experience chronic stress that shortens lifespan. A same-sex pair is the minimum, and the companionship is not optional.

Why does my guinea pig need vitamin C?

Unlike most animals, guinea pigs cannot synthesize their own vitamin C — it must come from the diet daily. Deficiency causes scurvy, which is fatal untreated. Bell peppers and fortified pellets are the primary sources.

How much hay does a guinea pig eat?

Unlimited — hay should be available at all times, and it should be about 80 percent of the diet. It wears down the teeth and provides the fiber their digestive system requires.

Can guinea pigs and rabbits live together?

Not recommended — rabbits can injure guinea pigs with their powerful kicks, and the dietary needs differ. Rabbits also bully guinea pigs for food and space. Separate species, separate housing.

The Bottom Line

Ten and a half square feet minimum for a pair, solid-bottomed with paper bedding, hiding spots for each pig. Unlimited timothy hay as 80 percent of the diet — it is the teeth and the digestion. Measured fortified pellets, one cup of vitamin-C-rich vegetables daily, and the C supplementation that keeps scurvy away. Never alone — a same-sex pair is the minimum, and the introduction takes weeks. Weekly weight checks, because the first sign of illness is often the last chance to treat it. Guinea pigs are more involved than the pet store display suggests — the hay, the C, the space, and the friend are the whole thing.