That dog is thinking, "If I wasn't so tired. I'd eat that rabbit!".
Speaking of dog attacks, let me share something as a public service announcement. I am NOT advocating any harm towards dogs. I love dogs. But if you are ever attacked by a larger dog, this could save your life. I learned this at USAF special survival school training. If a dog attacks you, stand your ground, face the dog, lean forward and stick an arm out with a fist. The dog will almost always attack the outthrust hand first. When the dog opens its mouth to bite your hand, shove your hand/arm down its throat as far as you can. You may receive some injuries, but far less than if you do nothing. Again, I am posting this as a method to save you or another if attacked by a larger dog that may seriously harm you.