Equus quagga, Boddaert, 1785
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https://doi.org/ 10.5281/zenodo.5719778 |
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https://doi.org/10.5281/zenodo.5719802 |
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persistent identifier |
https://treatment.plazi.org/id/03B0E520-E814-5860-FFB0-A181E90EF9C9 |
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Conny |
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Equus quagga |
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5 View On .
Plains Zebra
French: Zebre de Burchell / German: Steppenzebra / Spanish: Cebra de Burchell
Other common names: Common Zebra , Painted Quagga ; Burchell's Zebra (burchell), Chapman's Zebra (chapmanni), Crawshay's Zebra (crawshaii), Damara Zebra ( antiquorum ), Grant's Zebra (boehmi), Quagga ( quagga ), Zambezi Zebra (selousi)
Taxonomy. Equus quagga Boddaert, 1785 View in CoL ,
South Africa, south of Vaal River.
Revisions have been made to the taxonomy of the Plains Zebra , whose extant species complex was until recently named E. burchelli, with the extinct form designated as a distinct species, the “ Quagga ” (FE. quagga ), which occupied the former Cape Province, south of the Orange and Vaal rivers and west of the Drakensberg mountain range. Anecdotal evidence suggests that the ranges of Quaggas and “Burchell’s Zebra ” (E. q. burchelli ) overlapped in a narrow zone north of the Orange River, unlike the other Plains Zebra subspecies whose ranges do not overlap, but they apparently did not interbreed. However, recent molecular analyses using both mitochondrial and nuclear DNA demonstrate that the variation among living and extinct forms is no greater than among modern breeds of domestic Horses (FE. caballus ). Thus the Plains Zebra and the extinct Quagga are now considered a single species, E. quagga . The Plains Zebra shows a genetic and morphological cline from northern Kenya to southern Africa; generally, the farther south, the less the degree of stripe coverage, while body size increases. With the nominate subspecies’ demise, only six extant subspecies are recognized, located around three widely separated regional centres.
Subspecies and Distribution.
E. q. antiguorumC. H. Smith, 1841 — Angola, Namibia, andWBotswana.
E. q. burchelliGray, 1824 — CSouthAfrica.
E. q. chapmanniLayard, 1865 — NSouthAfrica, ZimbabweandEBotswana.
E. q. crawshaiDeWinton, 1896 — ZambiaEofLuangwaRiver, Malawi, SETanzania, andMozambique.
E. q. selousi Pocock, 1897 — E Zimbabwe and W Mozambique. View Figure
Descriptive notes. Head-body 217-246 cm, tail 47-57 cm, shoulder height 127-140 cm; weight 175-320 kg. The Plains Zebra is a muscular horse with a short neck, barrel chest, and sturdy legs. The stripes are variable, but in general they are wide, broader than those of Mountain Zebras (LE. zebra ) and Grevy’s Zebras ( E. grevyi ). Apart from Burchell’s and “Damara” Zebras,stripes cover the flanks and touch under the belly. Stripes on the rump are typically bold and wide in all subspecies except the Damara Zebra , where they are thin and often wavy. In Burchell’s and Damara Zebras, both southern African subspecies, there are often grayish shadow stripes in the center of the white stripes. In all subspecies, males are slightly larger than females and have stripes that are blacker than the browner ones of females.
Habitat. Plains Zebras inhabit tropical, subtropical, and temperate grasslands, steppes, savannas, and woodlands, from sea level to 4300 m on Mount Kenya. Since Plains Zebras need to drink daily, they are restricted to habitats where water can be accessed within half a day’s walk. Only deserts, dense woodlands, and permanent wetlands are avoided.
Food and Feeding. Plains Zebra are true grazers. As hindgut fermenters, they require large quantities of food, so it is not surprising that they spend up to 20 hours per day foraging. Yet they are selective foragers, disproportionately consuming Perisetum and Themeda grasses when available. They can only forage in mesic areas where feeding sites and watering points are close together.
Breeding. Plains Zebras give birth to one young after a gestation period of twelve months. Females generally stay near their groups when giving birth. When the foal is strong enough to move about, the mother and foal rejoin the group. Foals nurse for about six months, but begin feeding on grass by about one month of age. Females become sexually mature between two and three years of age, but often cycle without conceiving for the first year. Males generally only begin maintaining harems at five years of age.
Activity patterns. Plains Zebras are active day and night and organize their daily activities around drinking. Most individuals need to drink once per day, but in very dry conditions, some drink more often. During the dry season the need for water constrains Plains Zebra groups from wandering more than 5-10 km from reliable water. After the rains, they spread out and range widely, seeking superior grazing areas located near transient water sources.
Movements, Home range and Social organization. Because Plains Zebras are restricted to habitats where food and water are in close proximity, females of different reproductive classes can stay together. As a result, females, regardless of reproductive state, form groups and associate with a single male, who keeps away marauding males. By reducing sexual harassment, stallions provide females with a valuable material reward— increased foraging time. As in feral horses, females that associate with high-ranking males, or males rising rapidly in rank, can feed for up to six minutes longer per hour than females associating with less able males. Since Plains Zebras feed for up to 20 hours per day, females associating with the best males typically gain an additional two hours of foraging per day, thus increasing their fitness. Plains Zebra associations are often large, consisting of hundreds, if not thousands, of individuals. Since these herds include both harem and bachelor male groups, Plains Zebras live in the most complex societies of all equids. Herd size varies. It depends directly on the abundance of vegetation, but also on the strength of a social factor—the degree of cuckolding pressure exerted by bachelor males. When vegetation is abundant, groups tend to be large. But the largest herds form when bachelor groups are large. By banding together, breeding stallions amortize costs and collectively dominate large bachelor associations. For females, harassment reduction helps maximize foraging. Apparently females find life in herds no different from life in isolated and unchallenged harems, thus permitting herds to form. Many Plains Zebra populations are seasonally migratory, traveling hundreds of kilometers as they track vegetation flushes induced by predictable seasonal shifts in rainfall. Others stay put when the migrants leave, suggesting that these strategies are alternative solutions, shaped by trade-offs between vegetation quality and quantity. At any one locale, migratory or resident populations also exhibit local movements among landscape zones. During the rains, Plains Zebras graze on hilltops where vegetation productivity is high and good visibility increases safety from predators. When the rains cease and grasses stop growing, the zebras seek habitats where food is more abundant, because of dietary demands associated with their relatively large body size. They move to valleys and basins where grass is abundant, even though it is fibrous and of low quality. Their grazing transforms these habitats. Residual moisture and increased light penetration induces vegetation growth, which benefits the zebras as well as wildebeest (Connochaetes spp.) and Thompson's gazelles (Eudorcas spp.). As ruminants, these species require higher-quality vegetation than zebras. It is their good fortune that by the time they are forced to leave the hilltops, high-quality vegetation in the valleys is abundant enough to sustain them. Thus Plains Zebras play an important role as engineers stabilizing herbivore communities.
Status and Conservation. Classified as Least Concern on The IUCN Red List. In 2002, total numbers were estimated at ¢.660,000. More than 75% of the world’s Plains Zebras are “Grant’s Zebras” (boehmi), some 200,000 of them in the Serengeti-Mara ecosystem. The two countries they inhabit, Kenya and Tanzania, have extensive national park systems earning revenue from tourism, coupled with sophisticated government-supported monitoring systems. Wildlife-friendly ranching practices tend to protect even zebras living on private land in Kenya. Plains Zebras will probably not become threatened in these locales, but aerial survey data from Tanzania suggests a population decline of approximately 20% from the late 1990s to the mid-2000s. Elsewhere, Grant’s Zebras and the other subspecies are faring less well. Civil strife in many countries has led to widespread poaching. Continued habitat conversion to agriculture and loss due to development isolate and threaten the demographic and genetic integrity of small populations. In the past Plains Zebras have shown resilience and an ability to bounce back quickly from population reductions. With the establishment of effective management, protection, and monitoring, most Plains Zebra populations are likely to survive. Current information on total population size is limited.
Bibliography. Bell (1971), Bennett (1980), George & Ryder (1986), Groves (1974), Hack & Lorenzen (2008), Hack et al. (2202), Higuchi et al. (1984), Kgathi & Kalikawe (1993), Kingdon (1979, 1997), Klingel (1969), Oakenful et al. (2000), Ogawa (1975), Rubenstein (1986a, 1986b, 1989, 1994), Rubenstein & Hack (2004), Sinclair & Norton-Griffiths (1982), Smuts (1975).
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
