The plains zebra ( Equus quagga, formerly Equus burchellii) is the most common and geographically widespread species of zebra. Its range is fragmented, but spans much of southern and eastern Africa south of the Sahara. Six or seven subspecies have been recognised, including the quagga which was thought to be a separate species. More recent research supports variations in zebra populations being clines rather than subspecies.
Plains zebras are intermediate in size between the larger Grévy's zebra and the smaller mountain zebra and tend to have broader stripes than both. Great variation in coat patterns exists between clines and individuals. The plains zebra's habitat is generally, but not exclusively, treeless grasslands and savanna woodlands, both tropical and temperate. They generally avoid desert, dense rainforest and permanent wetlands. Zebras are preyed upon by and , and, to a lesser extent, African leopard, and African wild dogs.
Plains zebras are a highly social species, forming harems with a single stallion, several and their recent offspring; bachelor groups also form. Groups may come together to form herds. The animals keep watch for predators; they bark or snort when they see a predator and the harem stallion attacks predators to defend his harem.
The plains zebra remains common in , but is threatened by human activities, such as hunting for its meat and hide, as well as competition with livestock and encroachment by farming on much of its habitat. The loss of open grasslands due to woody plant encroachment increases predation risk and therewith habitat. Plains zebra are listed as near threatened by the IUCN as of 2016. The species population is stable and not endangered, though populations in most countries have declined sharply.
Northwestern Kenya (from Uasin Gishu and Lake Baringo) to the Karamoja district of Uganda. |
Zambia west of the Luangwa River and west to Kariba, Katanga Province of the Democratic Republic of the Congo, north to the Kibanzao Plateau, and in Tanzania north from Nyangaui and Kibwezi into southwestern Kenya as far as Sotik and southwestern Ethiopia from Omo Valley to Nechisar plains in the north and Yabello and Borena Zone to the east. |
Eastern Zambia, east of the Luangwa River, Malawi, southeastern Tanzania, and northern Mozambique south to the Gorongoza District |
North-east South Africa, north to Zimbabwe, west into Botswana, the Caprivi Strip in Namibia, and southern Angola. |
Southern Botswana to Etosha and the Kaokoveld, and southeast to Eswatini and KwaZulu-Natal. |
South Africa |
Mozambique |
Burchell's zebra was thought to have been hunted to extinction. However, Groves and Bell concluded that "the extinct true Burchell's zebra is a phantom". Careful study of the original zebra populations in Zululand and Eswatini and of skins harvested on game farms in Zululand and Natal has revealed that a certain small proportion shows similarity to what now is regarded as typical burchellii. The type localities of the subspecies Equus quagga burchellii and Equus quagga antiquorum are so close to each other that the two are in fact one and that, therefore, the older of the two names should take precedence over the younger. They suggested that the correct name for the subspecies must be burchellii, not antiquorum.
A 2005 genetic study confirmed the quagga being the same species as the plains zebra. It showed that the quagga had little genetic diversity and that it diverged from the other plains zebra subspecies only 120,000–290,000 years ago, during the Pleistocene and, possibly, the penultimate glacial maximum. Its distinct coat pattern may have evolved rapidly because of geographical isolation and/or adaptation to a drier environment. In addition, plains zebra subspecies tend to have less striping the further south they live, and the quagga was the most southern-living of them all.
The simplified cladogram below is based on the 2005 analysis (some taxa shared and could therefore not be differentiated):
A 2018 DNA study found no evidence for a subspecies structure in plains zebras but, instead, observed a north–south genetic continuum. Modern plains zebra populations appear to have originated from Southern Africa around 370,000 years ago with plains zebras in Uganda, the most northern population, being the most distinct.
Like all zebras, they are zebra stripes and no two individuals look exactly alike. Compared to other species, the plains zebra has broader stripes. The stripes are vertical on the fore part of the body, and tend towards the horizontal on the hindquarters. Northern zebra populations have narrower and more defined striping; southern populations have varied but lesser amounts of striping on the under parts, the legs and the hindquarters. Southern populations also have brown "shadow" stripes between the black and white colouring. These are absent or poorly expressed in northern zebras. The natal coat of a foal is brown and white and the brown darkens with age.
Various abnormalities of the patterns have been documented in plains zebras. Melanistic zebras have high concentrations of dark stripes on the torso but low concentrations on the legs. "Spotted" individuals display interruptions in black striping patterns. There have even been morphs with white spots on dark backgrounds. Striping abnormalities have been linked to inbreeding. Albino zebras have been recorded in the forests of Mount Kenya, with the dark stripes being blonde. The quagga had brown and white stripes on the head and neck, brown upper parts and a white belly, tail and legs.
Depending on the population, zebra herds may be sedentary, being highly dense with small ranges, or Animal migration, being less populated with separate, extensive dry and wet home ranges. When migrating, zebras appear to rely on some memory of the locations where foraging conditions were best and may predict conditions months before their arrival.
The loss of open grasslands due to woody plant encroachment increases predation risk and therewith habitat.
Plains zebras are adapted for grazing on both long, tough grass stems and newly emerging short grass. In some areas, it rarely feeds below to ground level. It ranges more widely than many other species, even into , and it is often the first grazing species to appear in a well-vegetated area. The flexible upper lip allows them to push plant material between the incisors to cut. Zebras have a less efficient digestive system than but food passage is twice as fast. Thus, zebras are less selective in foraging, but they do spend much time eating. The zebra is a pioneer grazer and prepares the way for more specialised grazers such as and Thomson's gazelles.
The plains zebra's major predators are and . Lions are most successful when targeting lone individuals, usually an old male while hyenas chase and isolate an individual from the group, usually a female or foal. also prey on zebras when they are near water. Less common predators include , and African wild dogs, which mostly hunt foals. When in the presence of a lion, zebras remain alert and stand in a semi-circle at as much as and no less than . Stallions sometimes try to drive lions away with bluff charges. By contrast, zebras may approach cheetahs and wild dogs and a single hyena is allowed to come within a few metres. To escape from predators, an adult zebra can run at . When being hunted by hyenas or wild dogs, a zebra harem stays close together and cooperates to protect threatened members, particularly the young. The harem stallion goes on the offensive and attacks the dogs or hyenas.
Multiple harems and bachelor groups come together to form larger herds of hundreds of animals, especially during migrations. Plains zebras are unusual among harem-holding species in forming these groups. In addition, pairs of harems may create temporarily stable subgroups within a herd, allowing individuals to interact with those outside their group. Among harem-holding species, this has only been observed in primates such as the gelada and the hamadryas baboon. Bachelor groups tend to be at the periphery of herds and when the herd moves, the bachelors trail behind.
Stallions form and expand their harems by abducting young mares from their natal harems. When a mare reaches sexual maturity and has her first oestrous cycle, she attracts the attention of nearby stallions, both bachelors and harem leaders. Her family stallion (likely her father) chases off or fights stallions attempting to abduct her. Even after a young mare is isolated from her natal harem, the fight over her continues until her oestrous cycle is over and it starts again with the next oestrous cycle. It is rare that the mare's original abductor keeps her for long. When the mare finally Ovulation, the male that impregnates her keeps her for good. Thus, the mare becomes a permanent member of a new harem.
Mares exist in a hierarchy, with the alpha female being the first to mate with the harem stallion and being the one to lead the group. When new mares are added to the group, they are met with hostility by the other mares. Thus, the harem stallion must shield the new mares until the aggression subsides. The most recently added females rank lowest. Females that become unfit or weak may drop in their rank, though. The female membership of a harem stays intact, even if a new stallion takes over. During herd gatherings, family stallions may be cordial towards each other, while the mares are less tolerant.
A stallion defends his harem from other males. When challenged, the stallion issues a warning to the invader by rubbing nose or shoulder with him. If the warning is not heeded, a fight breaks out. Zebra fights often become very violent, with the animals biting at each other's necks, heads, or legs, wrestling to the ground and occasional kicking. Sometimes, a stallion lies still on the ground as if surrendering, but once the other male lets up, he strikes and continues the fight. Most fighting occurs over young mares in oestrus and as long as a harem stallion is healthy, he usually is not challenged. Only unhealthy stallions have their harems taken over and even then, the new stallion gradually takes over, pushing the old one out without a fight.
Two main facial expressions are made by zebras; the greeting and threat. In both cases, the lips are pulled back and chewing motions are made. Greeting involves the ears sticking up and directing forward; while the threat involves the ears down. Zebras strengthen their social bonds with Social grooming. Members of a harem nip and scrape along the neck, withers, and back with their teeth and lips. Mothers and foals groom the most often, followed by siblings. Grooming shows social status and eases aggressive behaviour.
A newborn is capable of standing almost immediately and starts to eat grass within a week. Early on, a mother zebra keeps any other zebra away from her foal, including the stallion, the other mares, and even her previous offspring. Later, though, they all bond. Within the group, a foal has the same rank as its mother.
Mortality for foals is high in their first year of life and is usually caused by predation. However, zebra young are afforded more protection than those of species like wildebeest and hartebeest. A foal is usually weaned at around eleven months, but may suckle for longer. Females reach puberty before three years, and males after five or six. Young male zebras eventually leave their family groups as the relationship with their mothers fades after the birth of a sibling. The young stallion then seeks out other young stallions for company. Young females may stay in the harem until they are abducted by another stallion.
Zebras are threatened by hunting for their hide and meat, and habitat change from farming. They also compete with livestock for food, and fencing blocks migration routes. Civil wars in some countries have also caused declines in zebra populations. The zebra can be found in numerous protected areas across its range, including the Serengeti National Park in Tanzania, Tsavo and Masai Mara in Kenya, Hwange National Park in Zimbabwe, Etosha National Park in Namibia, and Kruger National Park in South Africa. Some stable populations live in unprotected areas.
The quagga was hunted by early Dutch settlers and later by to provide meat or for their skins. The skins were traded or used locally. The quagga was probably vulnerable to extinction due to its limited distribution, and it may have competed with domestic livestock for forage. The last known wild quagga died in 1878. The last captive quagga, a female in Amsterdam's Natura Artis Magistra zoo, lived there from 9 May 1867 until it died on 12 August 1883, but its origin and cause of death are unclear. In 1984, the quagga was the first extinct animal to have its DNA analysed, and the Quagga Project is trying to recreate the phenotype of hair coat pattern and related characteristics by selectively breeding Burchell's zebras.
The plains zebra is the national animal of the Botswana and its stripes are depicted on the country's flag. The flag stripes also represent racial harmony in the country. The zebra has also been associated with beauty and the women of various societies would paint much of their bodies in stripes. For the Shona people of Zimbabwe, the zebra is a totem animal, along with the eland, buffalo, lion and monkey. The zebra is praised in a poem as an "iridescent and glittering creature". Its stripes have symbolised the joining of male and female and at Great Zimbabwe, zebra stripes decorate what is believed to be a domba, a premarital school meant to initiate women into adulthood. In the Shona language, the name "madhuve" means "woman/women of the zebra totem" and is a given name for girls in Zimbabwe.
Zebras have also been represented in Western culture. They have been thought of as a more exotic alternative to horse; the comic book character Sheena, Queen of the Jungle is depicted riding a zebra. The film Racing Stripes features a captive zebra ostracised from the horses and end up being ridden by a rebellious girl. In the film Fantasia, two are depicted being half human and half zebra, instead of the typical half human and half horse. Zebras have been featured as characters in other animated films like Khumba, The Lion King and the Madagascar films.
Ecology
Range and habitat
Diet and predation
Behaviour
Social structure
Communication
Reproduction and parenting
Human interactions
Conservation
In popular culture
External links
|
|