This zebra is barking or braying to communicate with other zebras in its herd.
https://www.pexels.com/photo/white-and-black-zebra-standing-on-ground-1916645/

Bray

Zebras have another call, called a bray. This call is a low growl that ends with a squeak, like a pig. Zebras use this call when they are angry or trying to impress a mate.