Elephant Anatomy - Respiratory System

Owing to the sheer size of the magnificent elephant, certain adaptations have had to be made respecting their respiratory system. Mammals usually share the common trait of a pleural cavity; the space between the pleura, in which the lungs are situated. This lubricated membrane, the pleura, usually aids in respiration by exerting negative pressure on the lungs and thereby forcing them to expand so that the host can inspire (breathe in). However, elephants do not have this cavity. Rather, their ample lungs are attached directly to the chest cavity wall and the diaphragm. Elephants will breathe out an average of 310 litres of air every minute!

The elephant causes its lungs to expand and relax by moving the muscles in its chest. This is obviously a reflex and does not need to be consciously controlled by the animal. However, because it is so dependent on the movement of the chest and diaphragm, it is very important that the animal remains free of constriction or abnormal pressure in these areas. If an elephant's body is compressed in a way that causes the chest or diaphragm to be squeezed too much, the beast will die of suffocation. Their bodies are specially adapted so that their naturally enormous weight does not place too much pressure on their chest due to gravitational pull.

Collagen fibres are arranged in a loose formation around the lungs, connecting them to the chest wall. This network is loose enough to have no constricting effect on the function of the lungs. It is rich in capillaries so that blood supply to the area is ample and pleural fluid for lubrication.

The lungs themselves are divided into smaller units by a network of thick, stretchy septa. Each of the septal units measures approximately 10mm3. They are suspended on the septa in order to prevent the dependent alveoli from being compressed under the weight of the body or due to gravitation. The nature of the septa is such that they work to keep the intra-pulmonary system from being crushed due to gravitation by using tethering forces.

Air is inspired through the nostrils on the end of the trunk or through the mouth. From here, it passes through the nares, or nasal passages, located on the forehead under a circle of skin that is about the size of a dinner plate. Because the trunk is not the sole origin of fresh air, it can be used for holding water and dust without hindering the elephant's breathing.