The Snake's Lung

Back end of snake's lung is without dense blood supply that conducts gaseous exchange. This allows it to take these huge meals and then effectively crushes the whole front end of its body. It has this large, un vascularized portion of its lung at the back of its body which can be used as a bellows for pumping air in and out of the lung. I just cannot believe the lungs are still going. Are they ever going to stop? Cand actually demonstrate that to you.