A descendant of the wild guinea pigs of South America, today's domesticated guinea pig is viewed by many as an "easy" pet for children. Many parents select a guinea pig as a first pet for their child, believing a small pet needs only a small amount of care. It is important to understand that these little guys have lots of requirements, including a roomy cage, specialized diet, daily cleanup, and gentle handling, and that an adult should be the primary caretaker.
They may be small, but guinea pigs require ample space to move about. Make sure their living quarters are at least 18 inches wide, 14 inches high, and 25 inches deep. Guinea pigs housed in larger cages are more likely to be active. Do not use aquariums, as they provide poor ventilation, and mesh or wire-floor cages hurt guinea pigs' tender feet.
When choosing floor linings and cage furnishings, keep in mind that guinea pigs will chew on just about anything to wear down their constantly growing teeth, so everything placed in the cage must be nontoxic. Use plenty of lining material—shredded ink-free paper or commercial nesting materials available at pet-supply stores, for example—because guinea pigs will use the material as both bedding and bathroom.
Remember also to provide plenty of high-quality hay, which these rodents use for nesting and snacking. Do not use materials such as sawdust, cedar chips, or fabrics that may cause respiratory or other health problems. Finally, provide your guinea pig with a gnawing log (such as an untreated fruit tree branch), tunnels to crawl through, and platforms to climb on. Add a heavy food bowl resistant to tipping and gnawing and a water bottle with a sipper tube.
Guinea pigs are easily stressed, so they require careful handling. To pick up a guinea pig, slowly place one hand under his chest just behind the front legs, and gently cup your other hand under his hindquarters. Once you have a firm but gentle grip on the animal, lift him. Then immediately pull him close to your chest or lap so he feels safe and doesn't thrash around.
Feed your guinea pig a commercial guinea pig food, formulated especially for the species. These herbivores require a lot of vitamin C, so provide veggies such as kale and cabbage and ask your veterinarian about vitamin supplements. Treat guinea pigs to fruits, including melon slices and apples (but remove the seeds, which are toxic).
Guinea pigs try their best to keep clean, fastidiously grooming themselves with their front teeth, tongue, and back claws. But pigs—particularly the long-haired breeds—require frequent brushing and combing to stay clean and tangle-free.
Also, because their cage lining doubles as bedding and toilet, guinea pigs require daily housekeeping assistance. Scrub and disinfect the cage, then let it dry before lining the floor with fresh bedding and replacing the cage furnishings. Also clean the water bottle and sipper tube daily to prevent buildup of food, algae, and bacteria.
Guinea pigs are happiest when with other guinea pigs, so many pet care books urge owners to keep two or more together. Choose pairs that are the same sex and compatible. (For example, more than two male pigs together will likely fight.)
Source: The Humane Society of the United States