One of my rats died the other day. I'm wondering how important it is to get replacement rats for the one that's still alive. He was very close to the other rat, and he's not particularly social with people, so I'm concerned he's going to get depressed. I'd like to avoid getting more rats if possible, largely because I don't have a good space for quarantining any newcomers. But I will certainly do it if I think it'll make him happier. Are there any signs that might indicate he's lonely or depressed?
