Yes, you must house together at least two guinea pigs since they are social animals and tend to get depressed or lonely if they are kept alone. In the wild, guinea pigs live together in large herds, so you might want to replicate that in captivity.

Yes, guinea pigs should live in pairs. Guinea pigs are herd animals, meaning they need the company of their own kind to be healthy. Studies have shown that most guinea pigs who live in pairs are happier and healthier than those who live alone.