King Charles Cavalier Aggression

Question
I have an 11 month old Cavalier. I got him from a hobby breeder out of state. I made sure that he had all his necessary shots and papers. I noticed some aggressive behavior from him about 3 or 4 months ago when i bought him a hard rubber toy that dropped treats as a dog plays with it. At first he didn't seem interested so i picked it up in order to interact and get him interested in the toy. When I picked it up he snapped and growled at me intensely. I put the toy away, gave a firm "No" and sent him to his crate. Since that time this type of behavior has become more prevalent beyond possessiveness over toys. Now he sometimes growls if someone walks by him at mealtime, while he is napping and just at random times. Otherwise his general nature is obedient and loving. He is outside playing much of the day, he enjoys playing fetch and playing with other dogs. I just don't understand this aggressiveness.
Thank you for your help in advance,
Abbi

Answer
Neutering him if not already will help.  Have you obedience trained him?  With somebody the right age in the family, 4-H dog training is a great idea. In my area, clubs form soon after the first of the year. Even many urban areas have 4-H. For info look in your phone book under government listings for extension or cooperative extension offices. Ask specifically about a dog or canine club. The dogs see all the people and dogs in the household as a pack with each having their own rank in the pack and a top dog. Life is much easier if the 2 legged pack members outrank the 4 legged ones. You can learn to play the role of top dog by reading some books or going to a good obedience class. A good obedience class or book is about you being top dog, not about rewarding standard commands a treat.

One way to deal with the food aggression is to only start with part of his food in his dish.  When he finishes it, add more.  By going through a couple cycles of that every meal, he will soon welcome you near the food bowl.