Bats have a high metabolic rate and require a lot of oxygen to power their flight. They breathe more rapidly than other mammals, and their lungs are larger in proportion to their body size. Bats also have a special adaptation called the "nasal valve," which helps them to regulate their airflow during flight.
When a bat inhales, air enters through its nostrils and passes through the nasal valve. The nasal valve helps to control the amount of air that enters the lungs, and it also prevents air from flowing back out of the nose during flight.
The air then travels down the trachea and into the lungs. The lungs are lined with alveoli, which are tiny air sacs where gas exchange takes place. Oxygen from the air diffuses into the bloodstream, and carbon dioxide diffuses out of the bloodstream into the air.
The air then exits the lungs and passes through the trachea and out of the nostrils.
Bats are able to breathe while flying thanks to their powerful lungs and efficient respiratory system. They are able to maintain a high rate of oxygen consumption even during long and strenuous flights.