There's good news and bad news, Shopstump.
The bad news is that I'm afraid that you've inadvertantly made this problem worse by letting this happen repeatedly (ie the sequence of you reach for the bone, he growls, you not only retreat but have positive feelings about it all).
The good new is that many, many dogs object-guard. And while it may be a serious problem, it alone does
not indicate that your dog will be aggressive in other situations. The other good news is that it is treatable.
If it is only a certain type of bone that he guards, then I'd stop giving it to him. Why even go there? If he guards other objects as well, then you'll have to address it.
Erin is absolutely right. The best way to handle this problem is to teach 2 things 1) a "drop it" command and 2) that good things come from hands approaching him when he has a bone. What you
don't want to do is make him more defensive when he has a bone.
Joey used to have a similiar problem. This article from ClickerSolutions.com (an
excellent website BTW - have a look around) is basically what my trainer told us to do. It is also very similiar to Jean Donaldson's approach in her book,
Mine!, that Erin referenced.
http://www.clickersolutions.com/arti...ctguarding.htm
If you don't make rapid progress and/or his guarding to spreads to more objects, I would definitely consult a
positive trainer!
Good luck to you!