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What are the Differences Between Human Lungs and Other Mammals' Lungs?

All animals need to take in oxygen and get rid of the waste gas carbon dioxide. Small animals do this through the surface of their bodies. However, larger animals rely on specialized organs, such as lungs or gills, to accomplish this. Lungs are complex organs which all mammals have that allow them to breathe. The similarities between human lungs and those of other mammals are significant; yet, there are some interesting adaptations that some animals have made.

Function of the Lungs
- Mammals have two lungs on either side of the heart located near the backbone. The lungs have a spongy texture and are protected within the rib cage. The main function of the lungs is to exchange gases, and this takes place in thin sacs that are filled with air and surrounded with blood. A human breathes in and out from 15 to 25 times per minute. When you exercise, the rate goes up. There are wide differences between the respiratory rate for different mammals. An elephant breathes 10 times per minute when standing; dogs between 10 and 30 times per minute. The size of the lungs is relative to the size of the animal. There is a synchrony between breathing and locomotion for all mammals, including humans.
Shape of the Lungs
- There is little difference between humans and other mammals regarding the shapes of lungs. Most mammals have oval-shaped lungs. Yet the manatee family of marine mammals have lungs that are long and flat, and positioned lengthwise in the back; while humans and most other mammals have their lungs positioned in the ribcage. Manatees breathe through their nostrils and they can exchange 90 per cent of the air in their lungs, while humans exchange around 10 percent. According to marine experts at the University of Alaska, Fairbanks, marine mammals--including whales, dolphins, seals, sea lions, and walruses--have proportionately smaller lungs than humans and other mammals; yet theirs are more efficient in the exchanging of oxygen.
Role of the Mouth
- The respiratory system consists of the lungs, airways and blood vessels. Humans can breathe through their noses, as can most mammals. Most also can breathe through the mouth, with horses being an exception. Rabbits and rodents are also confined to nasal breathing. Human infants are often described as nasal breathers, but infants can, in fact, breathe through their mouths when they are crying.
Pleural Space
- Humans and most other mammals have a pleural space, which is a tiny area between the layers of pleura--the thin covering that protects the lungs. Usually, the pleural space is filled with fluid. Elephants are an exception. They lack this fluid-filled pleural space, and scientists believe this may help explain their ability to remain underwater for extended periods--breathing only through the trunk.

Animals & Science