If Sparky displays possessive behavior, his ancestors might be to blame. Before they were domesticated, dogs had to compete for everything from food to nesting sites. Possessive aggression was the only way to guard their treasures. Sparky's obsession with his food bowl or certain toys or people might trigger him to growl, snap or bite when you go near him. Although this is not personal, it's best to be safe than sorry and take steps to eliminate his possessiveness.
Remove items that might trigger Sparky's possessive behavior, because if he can't get to them, he can't guard them. Put away his food bowl after he's finished eating and place toys in an area where he can't get to them. Alternatively, lock doors or use baby gates or a dog crate to restrict his access if you must.
Teach your furry friend the "drop it" command. Bribe him with a dog treat when he has an object of his affection in his mouth. Hold the treat in front of his nose and say "drop it." To eat the treat, he must let go of the object. Praise him and give him the treat when he does. Immediately give the object back to your dog so he learns that he can trust you and that sharing results in pleasant rewards. With consistency, his possessiveness will diminish.
Use the "leave it" command to keep your dog from picking up toys or other items he might get possessive about. Show him a food treat and tell him to "take it." Do this several times. Again, show him a treat, but this time say "leave it," and close it in your fist. When your dog stops trying to get the treat, praise him, open your fist and give him the treat. With consistency he'll understand that not going after the treat gets rewarded. Use the "leave it" command on all items that your dog fancies.
Feed Sparky smaller portions of a less desirable dog food if he gets possessive over food. Avoid large treats, such as bones, that your pet companion can hide and guard -- give him several small treats throughout the day that he can eat within two minutes.
Play the food-toss game if your dog is possessive over you and dislikes your partner. Toss treats to your dog and slowly get the person he "dislikes" involved in the game. Hold a treat and move it around so your pet companion follows it with his eyes. Give the treat to your partner and tell your dog to "catch" as the treat gets tossed. Repeat this several times. Eventually the possessiveness subsides and your dog won't think of your partner as a threat.