Reptiles Breathe Air with Lungs
Living reptiles rely on lungs for air breathing, but their lung shape and internal structure differ widely. Many lizards and turtles have paired lungs, while many snakes have one dominant functional lung that runs along the body. Gas exchange occurs in small internal chambers, often called faveoli, rather than in the alveoli characteristic of mammalian lungs.
Ventilation Takes Different Forms
Many reptiles move air by using ribs and body-wall muscles. Turtles use specialised muscles around the shell and limb girdles because the shell prevents the kind of chest expansion used by many other animals. Crocodilians use a diaphragmaticus muscle to pull the liver backward in a hepatic-piston mechanism. These are solutions to the same problem, not steps on a single scale of complexity.
Breathing Changes with Activity and Temperature
Breathing rate can change with temperature, activity, diving and digestion. That normal flexibility does not mean visible respiratory effort should be ignored in a captive animal. Persistent open-mouth breathing, wheezing, discharge or marked lethargy should be assessed by a reptile-qualified veterinarian. Good ventilation, correct temperature ranges and suitable humidity support normal respiratory health, but the correct settings are species-specific.
