Like humans and most other animals, guinea pigs love being social. Humans and other guinea pigs are a good way to keep your guinea pig happy. There is one particular way that we as humans know guinea pigs are happy. If your guinea pig is weeking, popcorning, or running around the cage, this is a good sign they are happy.
What if my guinea pigs are not getting along?
Some guinea pigs take longer than others to be introduced. I have created a whole blog post about introducing guinea pigs to each other. Personally, I tend to get 2 guinea pigs at a time and try to stick with the same litter. This way they were raised together and there is less of a chance of issues in the future. If the guinea pigs are not getting along, separate them for a day or so. Once the time has passed introduce them to each other in a neutral place such as the floor or in a laundry basket. This insures that they are both on equal ground and ones scent is not already dominating the other.
Separation in the cage
While your guinea pigs are warming up to one another, I highly recommend separating the cage in half with a mesh divider. Doing this will make sure that the guinea pigs can smell and see one another with less of a chance of harming the other or themselves. Make sure to monitor your guinea pigs as much as possible the first week they are together and when you have the cage separated.
Human Interaction
Human interaction is also one way to help your guinea pig stay happy. Guinea pigs typically do not like being lap pets so there are other ways to have human interaction. The best way and simplest way to gain your guinea pigs trust and give them human interaction is having them eat out of your hand. When I cut up food for my salad and lunches I save the scraps to give to my two guinea pigs. The small amount of interaction a few days a week help your guinea pigs have social time. After a point, the guinea pigs will often let you just pet them while sitting at the edge of their cage. To train them to do this rewarding with treats such as a small piece of carrot can make them connect that it is a good interaction.