Question

Why some birds are said to have double respiration? Give some example of the birds

Answer 1

To match up to the high metabolic rate, and consequently high oxygen demand, of flying birds, they are known to have a process of double respiration. Although birds have lungs, they are very dependant on their air sacs for ventilation. Compared to mammals, bird lungs are smaller. The air sacs make up 15% of the body volume, compared to 7% lung volume in mammals. But, the air sacs do not have good blood supply, therefore they act as bellows and the gas exchange actually takes place through the respiratory system. This is essentially what is referred to as double respiration.

Sorry I could get any examples

Answer 2

Like mammals, birds don't have diaphragm and on inhaling and exhaling, their lungs don't expand or contract. Air moved in and out of respiratory tract through the pressure into the air sacs. So, the respiration in birds requires two respiratory cycles.