Eastern cottontail rabbits, like all mammals, obtain oxygen through the process of respiration. They inhale air through their nostrils, which then travels down the trachea into the lungs. In the lungs, oxygen from the air is exchanged for carbon dioxide in a process known as gas exchange. This exchange occurs in tiny air sacs called alveoli.
Once oxygen enters the bloodstream, it is transported to various cells and tissues throughout the body, where it is used for cellular respiration to produce energy. The carbon dioxide produced as a waste product of this process is then transported back to the lungs to be exhaled.
In addition to their respiratory system, cottontail rabbits also have adaptations that support their need for oxygen, such as efficient circulatory systems that help distribute oxygenated blood throughout their bodies, allowing them to be agile and active animals.