As a mammal, kangaroo has a respiratory system similar to human respiratory system. They breathe though their nose and mouth. They have a diaphragm and a pair of lungs which are sealed in pleural membranes inside the chest cavity and protected by ribcage. The lowering of diaphragm and expanding of ribcage create a negative pressure in lungs to draw air into lungs, so-called inspiration. Their breathing is linked to their hopping. During locomotion, the diaphragm move up to push out air of their lungs when their feet leave the ground; and the diaphragm move down to draw air into their lungs when their feet touch down to the ground. This automatic mechanism to empty and fill the lungs is very energy efficient when they are hopping at high
