Cats can eat plain, unsalted, shelled peanuts safely in small amounts, but peanuts are not toxic to cats. However, peanuts offer no nutritional benefit to cats as they are obligate carnivores who require animal protein. Feeding peanuts poses risks such as potential allergic reactions, digestive issues, obesity, and choking hazards especially if peanuts are salted, spiced, chocolate-coated, or still in the shell. It's best to avoid giving peanuts regularly and opt for cat-specific treats or meat-based snacks instead.