The elephant body structures are similar to the other mammals, excluding some special structures such as the trunk, tusks, respiratory and reproductive systems.
- Skeletal system
- Muscular system
- Integument system
- Respiratory system
- Gastrointestinal system
- Circulatory, hemopoetic and lymphatic systems
- Nervous system
- Urinary system
- Reproductive system
- Special sense organs
Because of the large body size of the elephants, the skeleton must be very large and strong to support the body weight. The whole skeleton weight is approximately 16.5 percent of body weight.
Figure 1. Skeleton of the elephant, Elephas maximus (a) and Loxodonta africana (b)
(modified from Redmond I., 1997)
The elephant skull is large but light weight because of the pneumatic bone which has air cavities making it appear like a honey comb or sponge on cut section.. Pneumatization of the bones of the skull occurs the elephant is 3-4 year old. The big skull allows strong attachment of muscles supporting the movements of the trunk, ear and jaw, and houses various organs especially the brain, eyes, ears, tusks, and upper part of respiratory and digestive tracts. The largest cavity in the skull contains the brain. Molar teeth are in the maxillary and mandiblar bones and the tusks alveolar sockets of the maxillary bones. The skull structure is not different between genders but the skulls of young elephants are more dorally ventrally flattened than those of adult elephants.
Figure 2. (Left) Air cavities in the cranium (Right) The elephant skull (Asian elephant) (modified from Redmond I., 1997)
The vertebral column of the Asian elephants are divided into basic five regions, cervical (7), thoracic (19-20), lumbar (4-5), sacral (4-5) and coccygial or caudal (24-33), the parentheses is a numbers of each region. The vertebral column is a curved linear, arch-like structure in Asian elephants, but is more nearly a straight horizontal line in African elephants. The movement of elephant vertebrae is limited because of fixed and tightened vertebral junctions.
The numberof ribs is 19-20 pairs depending on the subspecies for the Asian elephants, and 21 pairs for African elephants. The first six pairs of ribs are sternal ribs, the next nine pairs are asternal ribs and last four or so pair of ribs are true floating ribs in the Asian elephants.
These flat cartilages and bones lay in the pectoral position and serve as points of attachment for ribs and pectoral muscles, whileprotecting the organs in the thoracic cavity.