The skeleton of the elephant has been greatly influenced by the tremendous mass it must support. Incredibly, it weighs about 16.5 % of the total weight (A cow’s skeleton only weighs about 10 % of total weight). The backbone is the mechanism by which soft tissues are ‘hung’, consisting of sturdy vertebrae with high, strong neural spines in the chest (thoracic) area. Similar to man, the elephant has an almost vertical pelvis that is greatly expanded.
The ribs extend along most of the backbone and form an enormous barrel-shaped cage. The limbs are composed of segments in direct line with one another resulting in a rigid pillar of support for the huge mass of the elephant: it is as though an elephant is walking on four thick and upright pillars, which are long in the upper segment and short in the lower. Also, the majority of the marrow cavities in the leg bones have been replaced with a spongy bone aiding in the legs great strength and relatively light-weight.
As in all mammals, elephants have seven neck vertebrae. Unlike other herbivores, the elephant’s vertebrae evolved to have fused and relatively flat discs, which are able to handle the weight of the elephant tusks and head.
Much of the bulk of the cranium consists of ‘inflation’ – meaning the bones are compartmentalized with many air cells. Such a design makes the skull lighter, whilst still providing the strength needed. In addition, the greater surface area on the cranium yields more room for muscle attachment towards the back. This support is needed when we consider that the head of an adult male elephant may weigh up to 300 kilograms.