My dalmation had the same problem,but that was only with bones,but she would only nip and bite and growl at you if you stuck your hand near her bones,and she didnt even like the vaccuum(spell??)coming near her bones.We just left her alone when she was chewing on her bones,but you should get him neutered.and you should take him to obeidiance(spell??) class,too,that might help some.