Possessiveness of Toys
When your dog receives a new toy, especially one he's crazy about, his first reaction is to guard it carefully so no one steals it. He'll take his treasure to a far corner of the house or yard, hold on to it tight with his front paws and lick or chew it. And when someone approaches, his immediate instinct is to protect his find by growling, a trait passed on from his pack-living wolf ancestors.
Teach Him to Share
Some dogs can become so possessive that they will bare their teeth or snap if someone approaches them while they are playing with their toys. This aggressive behaviour is not acceptable and can be very dangerous, especially if small children or other pets are part of your household.
Not being possessive with toys is an important lesson to teach your dog. To train him to share with others, put his leash and collar on. Give your dog a new toy, then immediately ask him to give it to you by saying, "Drop it." The minutes he releases it, even slightly, praise him. If he refuses, ignore the toy and give him a few "sit" and "down" commands. These obedience drills will remind him that you are the leader of the pack and you are the one who decides whether he may have the toy or not. Repeat the obedience drills several times, then end the session by taking away his toy. "If he still fusses about giving you the toy, then take it away after he's finished playing with it and get rid of it.
Another way to prevent possessiveness is to offer your dog another toy or a food treat in exchange for the item he is playing with. Tell your dog to "Drop it," and as soon as he releases the item, give him the new toy. A few minutes later give your dog back the original toy, then repeat the exercise a few more times. By making a game of handing toys back and forth, you'll encourage your dog to trust you. Soon he'll be dropping what he has in his mouth as soon as he sees you approaching with something else in your hand.
If your dog gets hold of a real meat bone, it may be the one thing he will not be willing to give up, no matter what you offer him. In this case, it's best just to give in and let him have it, but don't offer the same item to him ever again.