Elephants are herbivores meaning they eat only plant matter, spending 16 hours a day collecting plant food. Their diet is at least 50% grasses, but also including leaves, bamboo, twigs, bark, roots, and small amounts of fruits, seeds and flowers. Because elephants can only digest 40% of what they eat, they have to make up for their digestive system's lack of efficiency in volume. An adult elephant can consume 140–270 kg (300–600 lb) of food a day of which 60% of that food leaves the elephant's body undigested.
Elephants are mammals, and the largest land animals currently living. The elephant's gestation period is 22 months, the longest of any land animal. The common birth weight of an elephant calf is 120 kilograms (265 lb). An elephant may live as long as 70 years, sometimes longer. Elephants are symbols of wisdom in Asian cultures, and are famed for their memory and high intelligence, elephants are considered to be on par with cetaceans and hominids. Aristotle once said the elephant was "the beast which passeth all others in wit and mind." Elephants are increasingly threatened by human intrusion and poaching. Once numbering in the millions, the African elephant population has dwindled to between 470,000 and 690,000 individuals. The population is now growing in some parts of Africa.
