Most vertebrates have a flexible chest that allows the lungs to expand and contract when they breathe. This is not how the turtles, which had long exchanged flexible ribs for a firm and protective shell. Different types of turtles have developed different methods of sucking air into the lungs. Turtles have also developed indirect ways to generate oxygen at times when they are not in contact with air, such as hibernation or when they are underwater.
In turtles, the lungs are located directly under the shell and above other internal organs. The upper surface of the lungs adheres to the shell itself, while the lower part is connected to the viscera (heart, liver, stomach and intestines) by a skin of connective tissue called diaphragmatic. The intestines themselves are also contained in a membrane that adheres to the diaphragm. Muscle groups change the volume of the abdominal cavity rhythmically. A set of muscles moves the intestine upward and pushes air out of the lungs. Other muscles contract and move the intestine away from the lungs, causing the lungs to expand and aspirate into the air.
When the turtles are walking, the movements of the front legs favor the suction and compression actions that ventilate the lungs. A turtle can change its lung volume by pulling and stretching its limbs again: turtles floating in the water can see and move their legs to facilitate breathing. A turtle that has been removed from its shell has no room in its lungs to breathe. At these and other times, turtles use different strategies to get oxygen.
A breathing aid is the tongue device, a system of sticks of bone and cartilage located at the base of the tongue. By raising and lowering the tongue device, the turtle’s throat goes up and down and attracts air. (This movement of air not only promotes ventilation, but also allows the turtle to better use the odor.) In strongly aquatic soft turtles, the neck is bordered with skin protuberances in the shape of fingers, the villi, which are supplied with a lot of blood. . The villi function like gills, expel carbon dioxide and absorb oxygen from the water. To treat oxygen-rich water, a soft bowl with its tongue appliance fills and empties the neck repeatedly in a process called buccopharyngeal breathing. Underwater, a soft shell generally pumps water in and out about sixteen times a minute. Turtles that hibernate underwater also exchange gases for the pharynx and allow water to circulate in the pharynx several times per minute. Many turtles practice this method of breathing, and some even absorb oxygen through the cesspool.
Many details on turtle breathing are unknown. However, it is clear that different types of turtles have developed different methods to meet your oxygen needs. Evolution has made them very good at getting this essential gas. As Ronald Orenstein indicates in “Turtles, Tortoises, and Pond Turtles: Armor Survivors,” turtles can breathe “with minimal effort and under all circumstances”.
