Elephants mostly stand while sleeping. They can also lie, but not for longer than an hour usually.
The reason is because their own body weight will crush their internal organs, so lying down for longer, would slowly cause their organs to be crushed. So, like horses, they sleep standing.
In general, elephants will sleep a maximum of four hours per day/night. They won't sleep at a stretch just like that of other domestic animals like dogs. They will sleep for about 30 minutes and then get up and feed on grass and then again they will go to sleep. But they will lie down for 30 minutes on the left side followed by the right side for 30 minutes. They repeat this cycle until they get about four hours of sleep.
Elephants also live in herds. An elephant herd may vary from 10 or 20 animals to fifty or more, most of whom are related.
The leader of the herd is usually a wise old cow, or female elephant. Most of her followers are females with young ones in various stages of growth. When two or more bulls join the herd at the same time, they are likely to fight each other, one would drive the other away, or even kill it.
The herd wanders far and wide, during the dry season they migrate into forests or stay close to a good supply of water.
The daily life of an elephant herd often follows a routine, in the morning hours the animals may travel to a nearby river. There they drink and bathe. After bathing, they feed on trees and other plants for several hours then they pause in some shady area for midday rest.
They may feed far into the night before taking another rest period. Some lie down to sleep, but many adults, especially among African elephants—sleep standing up.