dogs behavior with roommate

Question
I have a rescue dog who I've had a little over 2 months. He's a young adult, roughly 3 years old. He's a mixed breed and most likely has German Shepherd in him but he's a small guy at 40 pounds and 20 inches tall. I haven't had problems training him but lately I've been worried about his behavior with my roommate. He doesn't walk well on the leash with my roommate. He tries to take my roommate's food and will occasionally chew on my roommate's stuff. He hasn't chewed on any of my stuff. When he starts winding down for bed at night, if my roommate goes near him, he growls. He also growls at my roommate when he's eating and my roommate is near him. He hasn't done that with anyone else, not even my roommate's kitten. What can I do to make the situation better?

Answer
It appears that he is "resource guarding", and he doesn't respect your roommate the way he does you.  One thing you can do is to get a copy of Jean Donaldson's book "Mine! A Guide to Resource Guarding in Dogs" and both you and your roomie do the protocols outlined in the book with the dog.  This is a situation that could get worse, so do seek assistance from a good positive trainer or behavior professional in your area.  It might be a good idea to have your roommate take the dog to an obedience class alone without you.  For now, don't "test" the dog, lest someone get bitten.