During the day, this large animal naps for about 15 minutes in a standing position. In the evening, when the elephant is tired from its daily activities, it will fall into a deep sleep for 4 to 6 hours. Every day, elephants spend about 16 hours searching for food and only sleep about 3 to 5 hours. Adult elephants sleep standing up. Baby elephants sometimes sleep lying down. Elephants are big, but that doesn't stop them from becoming good swimmers. They love to swim and can even swim in the sea. Their favorite time of day is when they take a mud bath. The mud protects the elephant from the scorching sun and keeps it cool and away from nasty bugs. The size of an elephant means that when it is fully grown, apart from humans, it is safe from all predators. And to feed its great body, it must need a lot of food. Each adult elephant eats about 150 kg (300 lb) of grass, small branches, leaves, fruit, etc. every day. Such foods need to be chewed thoroughly. Elephants have grinding teeth at the back of the mouth, this is where the teeth have the strongest force, but it also wears away. Then the new tooth will grow at the bottom and push the old tooth out. Therefore, elephants grow teeth throughout their lives, a total of 6 sets of grinding teeth, but when the last set of teeth is worn out, the elephant will have lived to be 55 years old. It becomes weak from lack of food and will die more from starvation than from disease. Elephants use their trunks to grab food and bring it into their mouths. Their main food is grass and other plants on the ground. Elephants use their trunks to pull leaves, trunks and branches down from above. When food is scarce, elephants use their tusks to knock down trees. When thirsty, elephants gather on river banks or puddles, even using their trunks to dig deep to suck up water. Elephants drink water by sucking water into their trunk and then spraying it into their mouth. Every day elephants consume 160-300 liters of water. Elephants also spray water on their backs to cool their skin. Every day, adult baby elephants produce an amount of waste heavier than the weight of a young boy. Elephant dung contains tree seeds that elephants swallow and will grow into new trees to replace the trees they have eaten or knocked down. Currently, some countries are raising elephants, researching and testing the processing of elephant dung into paper (because elephant dung is quite clean and does not have a strong smell because they only eat plants and drink water).