Guinea pigs are in the Rodentia order, along with rats, mice, and hamsters. Guinea pigs are unique in that all of their teeth are open rooted, meaning all of their teeth are continuously growing (unlike other rodents, whose incisors are the only teeth that continuously grow). Guinea pigs weigh 1-2lbs full grown and live 5-6 years in captivity.
Guinea pigs are herbivores that need a high fiber content to keep their teeth healthy and for proper digestive function. They should always have access to a high quality hay such as Timothy or Orchard (Alfalfa can be given occasionally as a treat but is not ideal for their main hay source); hay should comprise at least 70-80% of their diet. A small amount a hay pellets can be fed (1/4 per day). Fresh veggies such as dark greens, parsley/basil/cilantro, carrots, broccoli, and zucchini can be fed in small amounts daily as treats. While there are many fruits that guinea pigs can safely eat, they should be fed very sparingly because of their high sugar content. Guinea pigs are often fearful of new things, so it is important to begin introducing them to different food types from a young age. Guinea should eat very regularly, not eating or defecating for more than 12hr is considered an emergency in rabbits.
Guinea pigs should have a minimum of 3ft d x 3ft w x 2ft h cage with a solid floor bottom to protect their delicate feet. Guinea pigs like to chew, so anything their cage is made of and anything in their cage should be non-toxic and without sharp edges. Bedding materials can include recycled paper products, newspaper, or aspen shavings (NEVER cedar shavings), and should be scooped daily. A nest box should always be available to provide a sense of security. Guinea pigs should be provided with enriching toys such as cardboard boxes, paper towel rolls, paper bags, willow balls and chewing baskets, and wooden toys to prevent boredom. They should be allowed out of their cage daily to run around an exercise.
Guinea pigs can be very social, friendly animals in a comfortable environment. They can be very shy and skittish if not properly socialized from a young age or if improperly handled. They are very vocal animals, and will “wheet” and squeak when excited or distressed.
Just like dogs and cats, guinea pigs should have yearly wellness exams by your veterinarian to check for illness. Common health problems include overgrown teeth and dental abscesses, gastrointestinal stasis (called ileus), mites, ovarian cysts, and respiratory disease. Some guinea pigs may also need regular nail and teeth trims.