Zebra
Communication

Zebras produce a number of vocalisations and noises. The plains zebra has a distinctive, barking contact call heard as "a- ha, a- ha, a- ha " or "kwa-ha, kaw-ha, ha, ha". The mountain zebra may produce a similar sound while the call of Grévy's zebra has been described as "something like a hippo 's grunt combined with a donkey's wheeze". Loud snorting and rough "gasping" in zebras signals alarm. Squealing is usually made when in pain, but can also be heard in friendly interactions. Zebras also communicate with visual displays, and the flexibility of their lips allows them to make complex facial expressions. Visual displays also consist of head, ear, and tail postures. A zebra may signal an intention to kick by dropping back its ears and whipping its tail. Flattened ears, bared teeth and a waving head may be used as threatening gestures by stallions.

Individuals may greet each other by rubbing and sniffing and then mutually rub their cheeks, and move along their bodies towards each other's genitals to sniff. They then may caress their shoulders against each other and lay their heads on one another. This greeting usually occurs between harem or territorial males or among bachelor males playing. Plains and mountain zebras strengthen their social bonds with grooming. Members of a harem nibble and rake along the neck, shoulder, and back with their teeth and lips. Grooming usually occurs between mothers and foals and between stallions and mares. Grooming establishes social rank and eases aggressive behaviour, although Grévy's zebras generally do not perform social grooming.
punctuation:no_comma