<P> There are three species of zebras: the plains zebra, the mountain zebra and the Grévy's zebra . The plains zebra and the mountain zebra belong to the subgenus Hippotigris, but Grévy's zebra is the sole species of subgenus Dolichohippus . The latter resembles an ass, to which zebras are closely related, while the former two look more horse - like . All three belong to the genus Equus, along with other living equids . </P> <P> The unique stripes of zebras make them one of the animals most familiar to people . They occur in a variety of habitats, such as grasslands, savannas, woodlands, thorny scrublands, mountains, and coastal hills . However, various anthropogenic factors have had a severe impact on zebra populations, in particular hunting for skins and habitat destruction . Grévy's zebra and the mountain zebra are endangered . While plains zebras are much more plentiful, one subspecies, the quagga, became extinct in the late 19th century--though there is currently a plan, called the Quagga Project, that aims to breed zebras that are phenotypically similar to the quagga in a process called breeding back . </P> <P> The name "zebra" in English dates back to c. 1600, from Italian zebra, perhaps from Portuguese, which in turn is said to be Congolese (as stated in the Oxford English Dictionary). The Encarta Dictionary says its ultimate origin is uncertain, but perhaps it may come from Latin equiferus meaning "wild horse"; from equus ("horse") and ferus ("wild, untamed"). The word was traditionally pronounced with a long initial vowel, but over the course of the 20th century, the pronunciation with the short initial vowel became the usual one in the UK and Commonwealth . The pronunciation with a long initial vowel remains standard in the United States . </P> <P> Zebras evolved among the Old World horses within the last 4 million years . It has been suggested that zebras are paraphyletic and that striped equids evolved more than once . Extensive stripes are posited to have been of little use to equids that live in low densities in deserts (like asses and some horses) or ones that live in colder climates with shaggy coats and annual shading (like some horses). However, molecular evidence supports zebras as a monophyletic lineage . The zebra has between 32 and 46 chromosomes, depending on the species . </P>

How many black stripes does a zebra have