Ruminant mammals, such as cattle and sheep, have four separate stomach chambers to break plants down into the nutrients they need. But elephants have a simpler, less efficient digestive system. Eating coarse vegetation is also tough on the teeth. Like other large grazing mammals, elephants have sturdy, high-crowned molars. But after the last set of molars has worn out, elephants may starve.
Elephants sometimes push trees over in search of food and can modify habitat over large areas.
This enhances their ecological importance but can be destructive now that elephants are largely confined to small reserves. Great eaters need great amounts of water, though exactly how much elephants drink daily isn't clear to me. Elephants that live in more arid areas of Africa may go without water for two or three days as they travel to new water holes. Elephants have a taste for alcohol. In Southeast Asia, they are known to seek out fermenting durian fruits.