At long last, Matrix was freed from his life of bondage as a backyard dog, a heavy chain around his neck for most of his life. He is considered a senior dog and probably ten years of age. You can't tell by his energy level. I walked Matrix the first time I met him at his kennel door, and he was super excited to go. His tail is not docked and it wags at high speed. Watch out behind! For all the years that he was chained, Matrix was easy to walk. In fact, I got him to heel in the first minutes of our walk. He's an obedient dog. I put on a brand new collar on him, and he stood still until I was done. When he hears his name, Matrix reacts instantaneously and his tail begins its supersonic wagging. He's a good and friendly dog. Matrix is presently my favorite at the shelter.