In Beasts of Bermuda, you can create friends and enemies.
Friends are made by creating a group and inviting other players to it. Carnivores and piscovores can only group with their species, while herbivores can group with other herbivores. Over time, your friendship with other players in your group increases from E grade to A grade. If your friendship becomes high enough with another player of the same species and opposite gender, you can nest with them. Being friends increases comfort and points.
Enemies are made when two carnivores, or a carnivore and herbivore, are too close. They will stress out and slowly become enemies, which decreases their comfort further.