Mysteries of elephant sleep revealed
Wild African elephants sleep for the shortest time of any mammal, according to a study. Scientists tracked two elephants in Botswana to find out more about the animals' natural sleep patterns. Elephants in zoos sleep for four to six hours a day, but in their natural surroundings the elephants rested for only two hours, mainly at night. The elephants, both matriarchs of the herd, sometimes stayed awake for several days.