Why Rabbits and Guinea Pigs Need Different Diets
If you’ve ever watched a rabbit and a guinea pig happily munching away together, it’s easy to assume they can eat exactly the same foods. After all, they’re both fluffy, both herbivores/fibrevores, and both seem convinced that hay is the greatest invention in history.
While they do share a love of hay, their nutritional needs are surprisingly different.
Hay is the Foundation
For both rabbits and guinea pigs, high quality grass hay should make up around 80 to 90% of their diet.
Hay helps to:
Wear down continuously growing teeth
Keep the digestive system moving properly
Provide the fibre needed for healthy gut bacteria
Timothy, meadow, orchard, oaten, and other grass hays are all excellent choices for healthy adult pets.
The Biggest Difference: Vitamin C
Here’s where guinea pigs become wonderfully unique.
Unlike rabbits (and most mammals), guinea pigs cannot produce their own Vitamin C. They must get it from their food every single day.
Without enough Vitamin C they can develop scurvy, which may cause:
Lethargy
Swollen joints
Poor wound healing
Loss of appetite
Dental problems
Fresh leafy greens rich in Vitamin C and a good quality piggy pellet help provide what they need.
Rabbits, on the other hand, make their own Vitamin C naturally, so they don’t require supplementation.
Pellets Aren’t One Size Fits All
Rabbit pellets and guinea pig pellets are formulated differently.
Piggy pellets contain added Vitamin C, while Bun pellets generally do not.
Feeding rabbit pellets to guinea pigs long term can leave them deficient in Vitamin C. Likewise, guinea pig pellets aren’t ideal for buns because they’re formulated for a different nutritional balance.
Think of pellets as a supplement to the hay, not the main course.
Fresh Greens Matter Too
Both species enjoy a variety of leafy greens, but introducing new foods slowly is always best.
Good options include:
Cos lettuce
Oak leaf lettuce
Coriander
Parsley (in moderation)
Endive
Silverbeet in small amounts
Offering a variety throughout the week helps provide different nutrients while keeping mealtimes interesting.
What About Treats?
Treats should always be exactly that… treats.
Fruit contains natural sugars, so small portions are plenty. Dried fruits are even more concentrated in sugar and should only be offered occasionally.
Healthy treats (such as ours) often focus on natural ingredients such as herbs, flowers, and leafy plants rather than unnecessary sugar or flour fillers.
The Takeaway
Although rabbits and guinea pigs share many similarities, they aren’t tiny interchangeable lawnmowers.
Providing the right diet for each species helps support healthy digestion, strong teeth, and a long, happy life.
When in doubt, remember this simple rule:
Hay first, fresh greens daily, species appropriate pellets, and treats in moderation.
After all, happy tummies usually lead to happy zoomies… or in the case of guinea pigs, a chorus of enthusiastic wheeks demanding a second dinner.
Related Creature Care: Why Rabbits and Guinea Pigs Shouldn’t Live Together