They don't need to be in prs, it is usually how they are sold, as I said in the above post, the one in my avitar was alone and has lived that way since I collected her. It is just interesting to watch a pr interact, breed and hunt, if I put a big serpent star with my other pr, they work together to over power the star and it is fascinating to watch the tactics they use, even a lg chocolate chip is fun to watch, they flip it and hold it down, which they can't do to a serpent star.