Supernatural – Fossil Series :Zebra Bone
Zebras evolved among the Old World horses within the last 4 million years. It has been suggested that zebras are polyphyletic 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.