B.M.
Ok..my son is the same way. He's two years old and in day care all day. If someone tries to grab his arm and lead him away from something he will try to bite you. I've learned from experience and many bites that biting back actually does work. I didn't want to do it at first but when I get bitten I bite him right back<not hard> exactly like he bit me. He gets that sad look on his face like he knows he did something wrong.Just last week at daycare his teacher told me she went to take him somewhere and grabbed his arm, and he went to chomp down and she said"no" and he instantly stopped what he was doing. So the improvement is there.