Dogs may be man’s best friend and cats may rule the Internet, but don't underestimate the charm of America's 12th most popular pet: the guinea pig.

In 2002, the American Society for the Prevention of Cruelty to Animals declared March to be National Adopt A Rescued Guinea Pig Month to raise awareness about guinea pigs in animal shelters.

Most pet stores sell guinea pigs that come from breeding mills, but thousands of the adorable critters are at shelters waiting for their forever homes.

These charming rodents make fun, low-maintenance pets, and they come in all different colors and coat types! However, there's a lot you probably don’t know about them.

Guinea pig hangs out in some fresh grass. Guinea pig hangs out in some fresh grass. (Photo: Birute Vijeikiene/Shutterstock)

1. Guinea pigs aren't pigs, and they aren't from Guinea

The rodents come from the Andes of South America, and the "guinea" in their name may be a corruption of Guyana, which is part of their natural range. Pet guinea pigs are descendants of wild ones that still roam the mountains and grasslands of South America.

2. They show happiness in the cutest ways

When guinea pigs are happy, they'll often hop up and down repeatedly, a behavior that's aptly referred to as "popcorning," which you can see above. The behavior is most common in young guinea pigs, but older animals may also exhibit it.

Guinea pigs are also notorious for being very "talkative" animals. While someone who hasn't spent much time around a guinea pig may assume they are just boring, expressionless rodents, that couldn't be further from the truth! They make a variety of sounds depending on their mood, including purring, squealing and chattering:

3. There's a reason "guinea pig" is synonymous with "test subjects"

Using the term "guinea pig" for test subjects came about because the animals have been experimented on since the 17th century. Today, mice and rats are more commonly used in research.

three guinea pigs

Photo: Roni G/flickr

4. They're herd animals

In the wild, guinea pigs live in small groups of five to 10. The group shares territory and acts as a community. Because they're social animals, pet guinea pigs do best when they're kept in pairs or small groups.

A guinea pig munches on some basil leaves. A guinea pig munches on some basil leaves. (Photo: TJ Images/Shutterstock)

5. You can't just feed them any old vegetable

The main fixture of any healthy pet guinea pig's diet should be fresh hay and hay pellets. Avoid any pellet "mixes" that include seeds, peanuts or anything else that is not explicitly made from hay.

In addition to hay and hay pellets, pet owners must be sure to regularly provide the critters with fresh fruit and veggies. This is largely because, like humans, guinea pigs cannot produce their own vitamin C. However, while fresh produce is vital, it's important to monitor their intake. While guinea pigs should be eating about one cup of fresh vegetables a day, fruit should only be given as a weekly treat (about 1-2 tablespoons for every 2 pounds of body weight). In moderation, carrots, tomatoes, zucchinis, wheat grass, apples are popular and healthy choices for a balanced guinea pig diet.

Additionally, it's important to familiarize yourself with the list of fruits and veggies that they should not be eating. For example, bananas, grapes, raisins are too sugary. Beans, broccoli florets and cabbage can cause gas. Spinach, kale, and other leafy greens can be toxic in excess. And iceberg lettuce? Well, it has absolutely no nutritional value at all!

A close-up look at a guinea pig's teeth. A close-up look at a guinea pig's teeth. (Photo: GrashAlex /Shutterstock)

6. Guinea pig teeth never stop growing

Guinea pigs have open-rooted teeth, which means they grow continuously. This is why it's important for pet guinea pigs to be provided with chew toys to keep their teeth at a proper length.


7. These little cuties are coprophagic

That's right — they eat their own poop. This may sound absolutely disgusting, but rest assured, it's a perfectly normal part of their digestive process.

As herbivores, guinea pigs subsist entirely on plant material, which can be difficult to fully digest and absorb all the necessary nutrients from on the first go. Because of this, they will often opt for a "round two" on their, ahem, already digested food to make sure they've eked out all the possible nutrients.

A guinea pig with a long-haired coat. A guinea pig with a long-haired coat. (Photo: cynoclub/Shutterstock)

8. They're used for food and traditional medicine in some cultures

Guinea pigs are important to many indigenous South American groups, and they're often used as a food source and in medicine. Folk doctors have used the rodents to detect illness by holding them to different parts of a sick person's body. When the animal squeaked, it was thought to be because it had found the source of the disease.

Hairless guinea pigs may look smaller than their hairy counterparts, but that's mostly just perception. There are even hairless guinea pigs! (Photo: Rosa Jay/Shutterstock)


This story was first published in March 2014, and has been updated with new images and information.