Snakes have lungs that extend along their long and thin bodies. However, the number, size, and shape vary depending on the species. The interior anatomy of their lungs is similar to that of humans and functions similarly to human lungs.
Like all vertebrate animals, snakes need lungs to obtain fresh air. This intake of oxygen enables their other organs to function properly. Lungs also help the snakes to get rid of unwanted substances like carbon dioxide from the body.
Do All Snake Species Have Lungs?
All snakes do have lungs. The position, shape, size, number, and functionality of lungs in snakes vary depending on the species though they are always clearly elongated.
Some snakes have two sets of lungs, while others only have one. Their lungs work in a similar way to human lungs.
How Do Snakes Breathe?
Snakes have nostrils, much like humans, and they utilize them to breathe in and out. To take a full breath of air, a snake usually uses both its nostrils and its glottis to breathe via its mouth, just like humans.
Snakes lack a diaphragm, a muscle that aids in the movement of air through the body. Instead, the snake expands and contracts its rib cage to transport air into and out of its lungs.
Related: Do Snakes Choke when Eating?
When they are breathing, their ribcage expands as the air gets in via their nostrils or glottis. Air travels down to the windpipe before moving and entering into the lungs.
Gases are then exchanged via the snake’s lungs. The air’s oxygen is then absorbed into the snake’s circulation system. Once oxygen is absorbed, they emit carbon dioxide by shrinking the rib cage to exhale it from the respiratory system.
Snakes that dwell and hunt in water also have a tiny air sac at the bottom portion of the right lung. They use the air pockets to store air they may require later as they still need oxygen from the atmosphere to breathe underwater. It’s as if they had a built-in air tank.
Hence, a sea snake may stay underwater for up to 2 hours without receiving a new intake of air. The interior of the sac resembles a balloon rather than a lung. At the air sac, respiratory gases are not exchanged.
However, these aquatic snakes can also breathe through their skin while in water, despite their skin being covered in scales. This mechanism is known as cutaneous respiration. While submerged in water, they transfer blood from their lungs to the capillaries in their skin.
The blood transports carbon dioxide to the snake’s skin, distributed into the surrounding water. At the same time, it takes oxygen from the surrounding water. Oxygen from the water is pulled up into their skin capillaries and absorbed into their blood before is taken to the lungs where gases are exchanged.
How Many Lungs Do Snakes Have?
The majority of snake species have only one functioning lung divided into two halves that cover the length of the snake. These species do not require the exchange of respiratory gases to live. Conversely, a few other species have two (right and left) lungs.
When snakes have two lungs, it is only the right lung that functions. Snakes with the right lung use their upper part to exchange gases, while its lower section stores air and acts as an air sac. The left lung is generally considerably smaller than the right lung and decreases until it becomes a vestigial remnant. Colubrid snakes, for example, have entirely lost their left lung, whereas boas have a functioning left lung.
Snakes with a tiny left lung or missing left lung have an additional internal organ, the trachea, which aids in breathing. It resembles a long straw and is held within the snake by cartilaginous semicircles. This snake-specific tracheal structure is frequently referred to as a tracheal lung, and it functions similarly to the snakes’ lungs.
Note: It does not matter whether a snake has one or two lungs. They will function in the same way.
Where Are a Snake’s Lungs?
The interior anatomy of a snake’s lungs is similar to that of humans, however, they are more spread out, frequently going past the snake’s chest.
Some snakes have two lungs that span the length of their body, one on the right and the other on the left. However, some snake species only have one lung. Aquatic snakes’ lung is found near the snakes’ tail (cloacas) and acts as an air sac for storing air.
The right-hand lung is present in all snakes. It is huge and spreads throughout the snake’s body, frequently past the snake’s chest. However, its length varies across snake species. It’s divided into two segments.
The section closest to the snake’s head has a respiratory function, where oxygen is exchanged. Whereas, the other half is positioned near the tail of the snake. This bottom of the right lung acts like an air sac. Its interior looks are more like a balloon than a lung. In this segment, respiratory gases are not exchanged.
All snakes have lungs, but the shape, size, and number vary depending on the species of the snake. Regardless of these differences, the lungs function in the same way.
Snakes usually expand or contract their rib cage when inhaling or exhaling. They breathe through their nostrils, glottis, or skin. The air is then taken down through the trachea before it is fed into the lungs. In the lungs, the exchange of respiratory gases occurs. Blood absorbs oxygen from the lungs and emits carbon dioxide into the lungs. The carbon dioxide is expelled from the lungs by shrinking the rib cage.
Joe is a freelance writer for FaunaFacts. Joe has written extensively about snakes for the site, but also contributes content about a range of animals.