New behaviors

Impulse seems to have realized he's a herding dog. When he's chasing along behind Hero now, he nips at Hero's hind legs-- something Hero does not appreciate in the least. Impulse hasn't started doing it to me or the kids yet, but he probably will sooner or later. I'm told it's a very common herding dog behavior. Hero did it as a puppy, too, but we were able to train him out of it eventually.

Also, Impulse has developed a new method of gaining the upper hand. When Hero's running along full speed, Impulse will suddenly dart at his side, grab him by the shoulder, and fling his whole weight against him. He's bowled Hero over more than once this way, which is pretty impressive given the difference in their sizes.