We have to guinea pigs, Pumpkin and Cinnamon, both male. Cinnamon is about 6 months older. Although they love hanging out together, sometimes fights break out and Pumpkin gets bitten by Cinnamon. They get to go outside and explore lots,so I don't think boredom is the problem. Even though it seems like Cinnamon is in charge, they still fight! We really don't want to have to separate them permanently because they are very sad and lonely when not together. Any ideas/tips are appreciated!