Under photopic conditions, however, humans can resolve stripes at distances 2.6 times greater than that of zebras, and at 4.5 and 7.5 times the distances of lions and spotted hyaenas, respectively. However, the dark vertical stripes stop abruptly at the flanks, leaving the belly white.  Bachelor groups tend to be at the periphery of herds and when the herd moves, the bachelors trail behind.  Mountain zebras can be found at elevations of up to 2,000 m (6,600 ft). built for grinding and cropping grass.  Civil wars in some countries have also caused declines in zebra populations. The plains zebra is the national animal of Botswana and zebras have been depicted on stamps during colonial and post-colonial Africa. Spatial vision refers generally to the ability to resolve spatially defined features.  Zebras are classified in the genus Equus (known as equines) along with horses and asses.These three groups are the only living members of the family Equidae. These images align well with our calculations (Table 2) that humans and lions can resolve the widest stripes of zebras under mesopic conditions, but cannot resolve stripes under scotopic conditions at distances beyond 16.4 m. Stripe visibility falls off from human vision to lion vision and as ambient light decreases. short distance (usually no farther than 20 miles away) of In the dry season, they can live on coarse, dry grass only if they are within a short distance of water holes. In 1417, a zebra was sent to the Yongle Emperor of China from Somalia as a gift for the Chinese people.  Molecular evidence supports zebras as a monophyletic lineage. capensis There are two distinct subspecies of mountain zebras (Equus zebra): Cape mountain zebras, E. z. zebra, and Hartmann's mountain zebras, E. z. hartmannae.Cape mountain zebras are found only in South Africa. Under photopic (daylight) conditions, humans with the best acuity possible (20/10) should be able resolve the widest stripes of our main species of interest–a plains zebra–at distances up to 360 m. A human with good average (i.e., 20/20) acuity would resolve stripes at half this distance (180m). Romans called Grevy's zebras 'hippotigris' and trained For more information about PLOS Subject Areas, click A limitation of our study is that the projected detection ranges are necessarily based on estimated CSFs, due to the impracticality of determining CSFs behaviourally for these species. The mountain zebra diverged from the other species around 1.75 mya and the plains and Grévy's zebra split around 1.5 mya.  Grévy's zebras can survive almost a week without water but will drink daily when it is plentiful and conserve water well. The skins were traded or used locally.  Zebras may spend seven hours a day sleeping. Plains and mountain zebras live in stable, closed family groups or harems consisting of one stallion, several mares, and their offspring. Luminance of the stripes of live zebras (E. grevyii) and the immediate surrounding area (sky, grass, dirt) above, below, to the left and to the right of the animal was recorded by ADM using an LS-110 Minolta Spot Photometer with a one-degree acceptance angle on August 29th 2012 at the Calgary Zoo. The species is classified as vulnerable by IUCN and has two subspecies. We additionally simulated the appearance of a small group of zebras from 16 m away and a large group of zebras in the distance (closest animals are at 111 m) for all targeted observers. a president of France in the 1880s who received one from non-anthropoid mammals) ; and (4) reliable CSFs of an afoveat mammal under a range of conditions ranging from scotopic through photopic are well described for domestic cats . Grévy's zebra populations are estimated at less than 2,000 mature individuals, but they are stable. These images demonstrate how stripe resolution is hindered as distance increases and is inversely related to acuity. Social grooming strengthens social bonds in plains and mountain zebras. This species lives in habitats with sparser resources and standing water and grazing areas may be separated. Unfortunately, we still have little idea of how predators or even conspecific zebras view striped coats in natural situations. predators are most active, zebras look indistinct and may For instance, Godfrey and colleagues wrote in 1987: “Zebras have always presented a problem to those interested in cryptic colouration, because in most types of open country in daylight they are exceedingly easy to see despite any disrupting effect of the stripes on their body outline.  The total population is currently estimated to be around 497 mature individuals, with low genetic variation indicating population fragmentation and drift. Downloaded on 17 January 2013. No, Is the Subject Area "Lions" applicable to this article? Next to providing a sanctuary for the rare Cape Mountain Zebra, The Park is also home to herds of Eland, Springbok, Kudu, Blesbok, Cape Buffalo and Red Hartebeest, to name but a few, and smaller predators such as the Cheetah, Caracal, Brown Hyena, African wild cat, Bat-eared Fox and Aardwolf. ", "Lessons for conservation management: Monitoring temporal changes in genetic diversity of Cape mountain zebra (, "The status of Namibia's Hartmann's zebra", https://en.wikipedia.org/w/index.php?title=Zebra&oldid=984073578, Wikipedia indefinitely semi-protected pages, Creative Commons Attribution-ShareAlike License, Modern range of the three living zebra species.  Plains zebras have been recorded travelling 500 km (310 mi) between Namibia and Botswana, the longest land migration of mammals in Africa. CH and ADM estimated the CSFs of lions, spotted hyaenas and zebras by matching a parabolic function to the existing domestic cat data under different lighting conditions, and then extrapolating to our species of interest by shifting the domestic cat CSFs to account for relative differences in eye size and estimated visual acuity (S1 Fig).  A 2013 phylogenetic study found that the plains zebra is more closely related to Grévy's zebras than mountain zebras. Following guidelines for using digital photography to study animal colouration , photographs were taken with a 300-mm zoom telephoto lens mounted on a Nikon D50 camera set at 70 mm in manual mode with EV default steps set at 1/3rd, on auto focus, and shot in RAW format. The San people associated zebra stripes with water, rain and lighting because of its dazzling pattern, and water spirits were conceived of having zebra stripes.  In the late 19th century, the zoologist Walter Rothschild trained some zebras to draw a carriage in England, which he drove to Buckingham Palace to demonstrate the tame character of zebras to the public. This hierarchy is observed in family groups while they are migrating.  A stallion may look after a foal in his territory to ensure that the mother stays, though it may not be his. https://doi.org/10.1371/journal.pone.0145679.g001, https://doi.org/10.1371/journal.pone.0145679.t002. The family stallion takes up the rear. The term commonly applies to the perception of stationary two-dimensional luminance patterns measured by resolution acuity or the contrast sensitivity function (CSF). Breeding After a gestation period of 365 days, Mountain Zebras give birth to a single foal. Non-primate mammals generally have better low-light sensitivity than humans due to the presence of a tapetum lucidum, a reflective “eye-shine” layer immediately behind the retina.