Zebras as very social animals and live in large groups called 'harems.' Plains and mountain zebras live in harems that are made up of one stallion and up to six mares and their young, while Grevy's zebras come together as groups for short periods of time. Sometimes herds come together to form temporary groups of up to 30 members. Zebras sleep standing up, and only when they are in groups that can warn them of danger. If they spot a predator, they will bark or whinny loudly to warn the others
