Once upon a time, the innocent potato found itself threatened by the ravenous guinea pig. No, really, this actually happened. Both our favorite furry potatoes as well as the standard variety originated in and around where is now known as Peru. The potato developed an alkaloid that's toxic to guinea pigs (and most mammals, really) as a means of defense. We hoomans can handle it, especially cooked, but the reason we don't eat green potatoes is because they contain high concentrations of those alkaloids. We can tolerate a few without ill effects, but raw potatoes are never a good idea for our guinea pigs. So can guinea pigs eat potatoes? Well, they probably will. But they shouldn't.
What's The Worst That Could Happen?
Maybe nothing. Maybe a sick guinea pig. Potatoes are high in carbohydrates, which serve no purpose for guinea pigs, especially if fed consistently over time. They are strict herbivores that graze on grasses and foliage in the wild. If your guinea pigs gets its paws on some potato peelings, sprouts, or leaves, monitor them closely for changes in behavior or abnormal poops.
What Should I Feed Instead?
While cooked potato peelings are sometimes fed to help sick or underweight guinea pigs bulk up with no ill effects, there are safer alternatives that serve the same purpose. Rolled oats, raw corn on the cob with husks, pellet mash with 100% canned pumpkin, or sneaking in a little extra fruit as a nutritious treat are healthy ways to help a recovering guinea pig put back on weight.
Sweet potatoes and yams don't contain the same dangerous toxins, so can be fed occasionally. Due to the starch content though, sweet potatoes are best reserved as a small treat once or twice a month. A guinea pig's regular diet should consist mainly of grass hay, with veggies that are high in vitamin c but low in phosphorus, calcium, starch, fat, oxalic acid, and sugar. Happy Cavy maintains a safe food list for easy reference.
Other Dangerous Foods 🚫
Your guinea pigs may not like to brag, but they are loyal, dedicated vegans. While they naturally tend to avoid those foods that aren't good for them, some may be more adventurous eaters than others. Restricting access to cat and dog food (meat-based) will keep the more experimental piggies safe. Any animal products should be avoided (meat, cheese, eggs, yogurt). Nuts and seeds (fattening and possibly a choking hazard), onions/garlic/leeks, mushrooms, raw beans and lentils, iceberg lettuce, avocado, coconut, rhubarb, and hot peppers, herbs, and spices are a few other unsafe foods. While guinea pigs greatly enjoy supervised grass time in nice weather, beware of buttercups in the yard or unidentified weeds. The ASPCA also has a helpful list of 17 common poisonous plants. Check out our more comprehensive list of dangerous foods for guinea pigs here.
A balanced and well-researched diet is key to a happy and healthy guinea pig. The toxic compounds in potatoes are best avoided, and the extra starch offers no benefit to a guinea pig's sensitive digestive system. There are plenty of other safe snacks and healthy treats to satisfy the proud, picky vegan piggy and curious eaters alike.