Because of the shorter thorax, the diaphragm is steeper in the '''ruminant''' compared to the '''horse'''. '''Avian''' species do not possess a diaphragm. Air moves in and out of their lungs via [[Avian Respiration - Anatomy & Physiology#Air Sacs|air sacs]]. | Because of the shorter thorax, the diaphragm is steeper in the '''ruminant''' compared to the '''horse'''. '''Avian''' species do not possess a diaphragm. Air moves in and out of their lungs via [[Avian Respiration - Anatomy & Physiology#Air Sacs|air sacs]]. |