Elephants are herbivorous, eating roots, grasses, leaves, fruit, and bark. Because of their huge size and low digestibility of the food they eat, elephants spend most of their time eating – up to 75 % of their day. Bulls can eat up to 130-260 kg of food each day, depending on their size and habitat. Only about 40 % of this is digested. On average it takes 24 hours to digest a meal.
The size of an elephant’s mouth is relatively small for the size of their body and can’t be opened very wide. To aid in the initial digestive process, there are well-developed salivary glands in the mouth, along with mucous glands in the oesophagus. Together they help to lubricate the coarse vegetation of the elephant’s diet.
The stomach is a single sack, lying almost vertically. It is an unusual cylindrical shape, with the middle region being partly glandular. The stomach acts more as a storage space than a digestive organ.
The diet of an elephant is primarily vegetation and as a result, bacteria in the gut are responsible for the digestion of cellulose through fermentation. This takes place at the junction of the small and large intestines where there is a huge sacculated caecum or sac. Products of digestion are absorbed through the relatively thin and vascularised walls of this sac.
Elephants also drink great quantities of water, over 190 l per day. They do this by inhaling the water through the trunk and then blowing it into their mouths. One trunkful of water can measure can contain 14 l of water. Elephants also inhale water to spray over their bodies to keep cool. On top of this water coating, the animals then spray dirt and mud, which acts as a protective sunscreen.