Animals Pets 8 Fascinating Facts About Guinea Pigs By Laura Moss Writer University of South Carolina Laura Moss is a journalist with more than 15 years of experience writing about science, nature, culture, and the environment. our editorial process Laura Moss Updated December 29, 2020 Neil Irving / EyeEm / Getty Images Share Twitter Pinterest Email Animals Wildlife Pets Animal Rights Endangered Species Guinea pigs are domesticated rodents from South America. Believed to be related to a wild species that is now extinct, guinea pigs are found throughout the world. The term guinea pig came to mean test subject due to the use of the animal for scientific research beginning in the 17th century. These charming rodents, which range from eight to 10 inches long and weigh between 25 and 39 ounces, are bred in a variety of colors and coat types and make fun, low-maintenance pets. From their elaborate communication style to their continuously growing incisors, there’s much to learn about these friendly rodents. Here are a few things you may not know about guinea pigs. 1. Guinea Pigs Aren't Pigs Texel guinea pig. Alexandra Jursova / Getty Images These tailless rodents come from the Andes of South America, and have no relation to pigs. Also called cavies, the "porcellus" in their scientific name, Cavia porcellus, means piglet. Male guinea pigs are called boars, females are called sows, and baby guinea pigs are known as pups. There are 13 breeds of domestic guinea pigs, with variations in color, coat length, and texture. The American Cavy Breeders Association recognizes the following breeds: American, American satin, Abyssinian, Abyssinian satin, Peruvian, Peruvian satin, silkie, silkie satin, teddy, teddy satin, texel, coronet, and white crested. 2. They're Vocal Animals Guinea pigs are notorious for being “talkative" animals. They communicate using a variety of sounds depending on their mood, including purring, squealing, squeaking, chirping, whistling, and whining. When they’re excited, about food or play, guinea pigs will emit a whistle or chirp sound. Guinea pigs can also purr like cats, which is sometimes, but not always, a sign of contentment. When guinea pigs make sounds of hissing or their teeth are chattering they are usually annoyed. 3. They Show Their Emotions When guinea pigs are happy, they'll often hop up and down repeatedly, a behavior that's aptly referred to as "popcorning." The behavior is most common in young guinea pigs, but older animals may also exhibit it. Guinea pigs also do the opposite, remaining completely still when they observe a threat. A herd of guinea pigs will work together when frightened — the entire group will scatter in different directions to baffle a potential predator. 4. They're Herd Animals Andra Boda / EyeEm / Getty Images Gregarious by nature, guinea pigs generally prefer to live in pairs or small groups. In fact, this is such an important element of their quality of life that Switzerland requires pet owners to keep a minimum of two guinea pigs. A group of guinea pigs, called a herd, shares territory and acts as a community, with an alpha male in the dominant position. Male guinea pigs, or boars, are more aggressive when competing for potential mates, so it’s best to keep boars separated when females, or sows, are present. 5. They Need Their Vitamins Ian Fox / Getty Images In order to maintain good health, pet guinea pigs need a balanced diet. The main fixture of a healthy diet is fresh grass hay, which provides fiber and something hard and crunchy to keep their teeth a manageable length. Guinea pigs also require specially formulated pellets that contain vitamin C. Like humans, guinea pigs cannot formulate their own vitamin C and must get it from their diet or supplements. Favorites of these herbivores are leafy greens like romaine and red and green leaf lettuce. They also enjoy fruit, but it must be given in moderation, as the high sugar content can have an adverse effect on their digestion. 6. Their Teeth Never Stop Growing Oleksandr Shchus / Getty Images Guinea pigs, like other members of the rodent family, have open-rooted teeth, which means they grow continuously. A quick glance at a guinea pig’s face reveals its long front incisor teeth — but guinea pigs actually have 20 teeth in their triangular-shaped mouths. It's important for pet guinea pigs to be provided with chew toys to gnaw on to keep their teeth at a proper length. 7. They Are Coprophagic Guinea pigs, like the world’s largest rodents, capybaras, eat their own poop. It’s a necessary part of their daily routine that allows them to get the bacterial flora they need for digestion. As herbivores, guinea pigs subsist entirely on plant material, which can be difficult to fully digest and absorb all the necessary nutrients the first time around. Because of this, they will often opt for round two on their already digested food to make sure they've eked out all the possible nutrients. 8. They Are Sometimes Used for Food Beginning with their domestication as early as 7,000 BCE, guinea pigs have been a source of meat for people in the Andes. The meat, which is high in protein and low in cholesterol, continues to be a fixture of the diet in some regions of South America. As livestock, guinea pigs are favored because they are easy to feed, reproduce rapidly, and can be raised in a small space in an urban environment. In order to protect biodiversity in Africa, efforts are underway to discourage the consumption of bushmeat and replace it with guinea pig meat. Workshops linking South American and African farmers to share benefits and techniques of breeding the animals have been productive. While environmentalists promote the consumption of guinea pigs as a low-impact alternative to beef, in the U.S., where guinea pigs are viewed as family pets, the idea is less popular.