Cheetah - Acinonyx jubatus vs. Human - Homo sapiens
The respiratory system of a cheetah is very similar to that of a human, but with some very specific adaptations that enable it to be the fastest land animal that has ever lived.
Two specific adaptations make a cheetah the incredible running machine that it is…one being the super-compensation of oxygen flow. It is suggested that cheetahs take in approximately 30-50% more oxygen during a bout of sprinting then they actually need for oxygenation of the organs and musculature. This is postulated to be used for air-cooling of the system since cheetahs cannot reduce body heat by sweating, and to ensure that every muscle fiber is always adequately oxygenated during these explosive bouts of running.
The second adaption that makes cheetahs insanely fast is their ability to use body mechanics for breathing, if you watch the cheetah in the video you can see how the thorax goes through full flexion and extension. You will also note that you don’t see any panting or really any head movement at all. As the cheetah goes through this full range of rib cage motion it is literally pushing air out and sucking air into it’s lungs.
Humans on the other hand can detrimentally affect their running with exaggerated breathing movement of the rib cage or more precisely of the spine. As our society becomes more adept to sitting and sedentarism, human breathing is moving more towards a secondary respiration or superior movement of the rib cage. Over time humans may lose ability to expand the thoracic rib cage to allow for full diaphragm excursion as well as full lung expansion. This in turn can cause a runner to revert to using thoracolumbar flexion/extension (like the cheetah) to draw in to and push air out of the lungs. This is not how we were designed to breathe.
Adaptation is always occurring int the favor of the organism, what we need to realize is that our environment is directing our adaptation. The cheetahs adaptation for maximum, short-burst speed has adapted it to become a smaller and weaker cousin to its savannah mates like lions.
Like the cheetah we have sacrificed technological supremacy for biomechanics optimization. So in the end, adaptation is always occurring, but we are one of, maybe the only, organism that completely determines it’s environment.