Lonely?

About a month ago, I adopted a five year old male chinchilla named Chubbs. He had been with his previous owner since he was a baby. His previous owner said that he was very aggressive with other chinchillas, but he got along very well with her three cats and two black labs. She never picked him up, and very rarely touched him... his playtime consisted of her opening his enclosure and letting him out until he lets himself back in. I don't have any other pets, but I do give him a lot of attention. He is very gentle and likes to be pet and will eat out of my hand. He likes to nibble on my nose and he takes treats right out of my mouth. I was actually very surprised at how great he is with humans for a chin who hadn't been handled often. Here's my concern: He sometimes barks, which I've read is a way to communicate with other chins. I've played sound clips of chins barking and he responds by barking back. Is this instinct or he lonely? I live with two other people, all of whom give him attention very frequently while he's active. Another chin is clearly out of the question, but my roommate has expressed interest in getting a dog lately -- maybe that will help?