Zebras generally live on the prairie where predators are infested, and are the foods that large carnivores like very much. They have no resistance. When they encounter a predator, they can only run away. If they lie down and sleep, they will slow down when they get up. So Zebra trained a unique skill: stand and sleep!
In addition, the zebra is not so serious and cautious, but a very lively and funny voice, coupled with the smile that often appears inadvertently, let them get a nickname: Ma Zhongshu.