african bark black coats black skin Bray common zebra equids fast grant’s zebra grazers herbivores herbivorous herd herds individual mammal patterns plains zebra social stripes ungulates unique white fur white stripes zebra Africa animal creature exotic free natural nature plains safari savannah striped untamed wild black-&-white black-coats black-skin common-zebra grant’s-zebra greyscale monochrome plains-zebra white-fur white-stripes erect manes harems mohawk-like manes stiff manes erect-manes mohawk-like-manes stiff-manes gray grey patterned barking braying Camouflage contrast contrasting equus-quagga-boehmi family-groups mammals subspecies unique-stripe-patterns