Plains zebra

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Plains zebra
Plain zebra of the subspecies Burchell's zebra (Equus quagga burchelli) in Etosha National Park

Plain zebra of the subspecies Burchell's zebra ( Equus quagga burchelli ) in Etosha National Park

Systematics
Subclass : Higher mammals (Eutheria)
Superordinate : Laurasiatheria
Order : Unpaired ungulate (Perissodactyla)
Family : Horses (Equidae)
Genre : Horses ( equus )
Type : Plains zebra
Scientific name
Equus quagga
Boddaert , 1785

The plains zebra ( Equus quagga ) or horse zebra is a zebra from the horse family ( Equidae ) and belongs to the order of the odd ungulate (Perissodactyla). Today it is the most common type of zebra in Africa and is distributed from the northeast to the south of the continent. It lives gregariously in small herds and feeds mainly on grasses. In contrast to the other horse species of today, it also occurs in partially closed landscapes. The stock, the largest population of which lives in the Serengeti today, is not considered endangered. A distinction is made between six recent subspecies, which mostly differ from one another in the stripes.

features

Habitus

Plain zebra of the subspecies Boehm's Zebra (= Grant's Zebra) ( Equus quagga boehmi ) in the Ngorongoro Crater , Tanzania
Plain zebra of the subspecies Chapman's zebra ( Equus quagga chapmani ) in Zambia

The plains zebra is the smallest of the zebra species living today and reaches a head-trunk length of about 230 cm, a height at the withers of 110 to 145 cm and a weight of about 175 to 385 kg. The tail length is 52 cm. Females are on average a bit smaller. The zebra shape is characterized by relatively short legs and characteristically broad, horse-like hooves. The typical chestnuts , callous-like protuberances on the legs, are smaller than in the mountain zebra ( Equus zebra ), but larger than in the Grevy's zebra ( Equus grevyi ). The tail is black or white in color, the mouth is black in color, while the rounded edges of the usually short and dark ears are white. Another typical feature is the short standing mane that extends from the top of the head to the withers ; however, it does not occur at all in some populations, especially in the northern range.

The plains zebra is characterized by the widest stripes compared to the other two zebra species, the Grevy and the mountain zebra. The stripe pattern of the plains zebra shapes is extremely variable, both locally and individually, but the leg markings always extend far beyond the sides of the body. Depending on the local shape, the color of the stripes differs from lacquer black to dark red-brown, the light basic color is usually clear white, only the extinct quagga had a yellowish-brown body color, but the belly and legs were white. The subspecies Boehm's zebra in East Africa has the widest stripes today, so-called "shadow stripes", which sometimes overlap the white stripes, hardly occur here. The stripe drawings become narrower, but less so with populations that live in the south, where "shadow stripes" also appear very often. In contrast to the other zebra shapes, some of the vertical stripes continue on the stomach. At the back, the stripes tilt horizontally. The stripes on the legs are also horizontal, but some populations, especially in southern Africa, no longer have leg stripes, such as the Burchell's zebra. Occasionally there are completely black colored animals with irregularly distributed white spots. The stripes are already formed in the embryonic age at three weeks, which is earlier than in the other zebra species.

Skull and dentition features

The skull of the plains zebra is between 44 and 49 cm long and long and narrow, but with wide zygomatic arches . The forehead line is characteristically convex, the occiput extends beyond the joint attachment surfaces of the cervical vertebrae (condyles) and has a distinct bulge for the attachment of the neck muscles. The nasal bone is relatively delicate, but clearly convexly curved. As in all modern horses, the interior of the nose between the nasal bone and the intermaxillary bone has a large extent.

The lower jaw, which is 41 cm long on average, is solidly built with a strong lower jaw bone and high joint surfaces. The bit is only slightly reduced and has the following dental formula in adult animals: . In some populations, which are mainly observed in the southern area of ​​distribution, the incisors do not show any enamel invaginations ( infundibulum ). The canine tooth is not always developed in females and if so, it is much smaller than in males. There is a large diastema to the posterior teeth . The molars generally have high crowns and a lot of dental cement , the premolars are similar to the molars and are therefore clearly molarized. The tooth enamel shows characteristic folds on the chewing surface. On the lower molars, at the rear end of the teeth on the tongue side, between two prominent enamel projections ( metaconid and metastylid ) there is a clear, rather V-shaped depression, due to which the plains zebra is counted among the stenonine horses.

Sensory performances and vocalizations

The plains zebra reacts to the stripe pattern of its conspecifics and is able to differentiate them by it. A total of six vocalizations are known. A two-syllable alarm sounds when a predator is sighted, a loud snort from the stallion when entering potentially dangerous terrain. Stallions squeak when bitten or keep snorting when satisfied. Foals make a pitiful tone in stressful situations. When greeting or making contact, the animals make an A-ha or Ka-ha -like sound.

distribution

Distribution area (red) of the plains zebra

The plains zebra is the most common of all three zebra species. The distribution area extends from the semi-desert steppe areas of southern Sudan and southern Ethiopia over the savannas of East Africa to South and Southwest Africa . But it does not reach the southernmost, often mountainous areas in the Cape provinces of South Africa . Originally, the steppe zebra was widespread in large parts of North Africa in the Pleistocene, under more favorable climate and vegetation conditions.

The plains zebra prefers short grass, but is not dependent on it. Therefore it has a very extensive habitat. It is therefore also find different from the other horse species in partly enclosed grass and parklands that of acacia - and Commiphora are interspersed inventories directly. Only on Lake Turkana is the zebra shape tied to fall seed grass landscapes. It is also often the first herbivorous species to appear in a grassy region. Only after the plains zebra has eaten the long grass and trampled it do wildebeest and gazelles follow . In addition to the lowlands, it also populates plateaus. On Mount Kenya , the plains zebra has been detected up to an altitude of 4,400 m. The population density is sometimes quite high and varies between 0.7 and 9.5 individuals per square kilometer. In the Ngorongoro crater this increases to up to 22 individuals per square kilometer. In the northern distribution area the steppe zebra lives partly sympatric with the Grevy's zebra. The southern populations hardly overlap with the mountain zebra that also lives there.

Way of life

Territorial behavior

Group of plains zebras of the subspecies Burchell's zebra ( Equus quagga burchelli ) in Etosha National Park

Similar to the mountain zebra, the plains zebra is a very social animal. It usually lives in small family groups or herds with a hierarchical structure, which consist of a single stallion, one to several mares and their offspring (the so-called harem). The group size depends on the quality of the living space. The worse the living conditions, the smaller the herd size. The largest groups have up to 15 members (stallion, six mares, eight foals), but the average is four to eight. According to studies in central Kenya, the individual animals in a group are partly related to one another. The herds do not maintain their own territories, but have action areas ( home ranges ) in which they predominantly stay and which can extend over a height difference of up to 1,100 m. The edges of these areas clearly overlap with those of other plains zebra groups. At times the individual herds also form larger associations. In large plains zebra associations, however, there is no superordinate organization beyond the individual groups. In addition to the actual herds, there are also "bachelor groups" of young males who have not yet established their own herd. These can also contain up to 15 animals. Purely female herds, on the other hand, are extremely rare.

Plains zebras of the subspecies Boehm's zebra ( Equus quagga boehmi ) in the Serengeti - Masai Mara ecosystem

The cohesion within the herd is very high, lost members are searched for over a long period of time. As a rule, the highest-ranking mare leads the group, while the stallion brings up the rear at the end of the procession; however, he is the first to drink, which usually takes place at night. The stallion covers the faeces of the mares and young animals with his feces and urine and usually shows a flehmen . At night, the herds prefer to stay in the open. At least one animal keeps watch to protect against predators, and young animals are the first to be woken up when danger approaches. When two herds meet, the stallions perform a ritualized greeting ceremony, consisting of the characteristic gesture of greeting - ears raised and pointing forward - and mutual sniffing of the nose and genitals . A steppe zebra in distress puts on its ears and, when the threat increases, spreads its lips and shows its teeth, a facial expression that resembles the pleading and the brusque face. Fights rarely take place and usually occur when a herd is attempted to be taken over by a foreign dominant stallion. If the previous herd leader loses this dispute, he leaves the group, with some male descendants following him.

nutrition

Boehm's zebras ( Equus quagga boehmi ) at the waterhole

The plains zebra is a herbivore and with its high crowns on the molar teeth and the high proportion of dental cement it is adapted to silicic acid-containing grass food ( grazing ), which makes up 90% of its food spectrum. With this zebra species, no large selection of plants can be seen. At least 23 different types of grass are consumed; sweet grasses such as Themeda , Cenchrus as well as dog-tooth and love grasses are particularly popular . Plants that are less frequently eaten also include lamp-cleaning grasses or millets such as fingergrass . In addition, herbaceous plants can occasionally be included, of which around ten species are known to be eaten by the plains zebra. Throughout the year the plains zebra visits different regions and migrates from areas with little to those with higher precipitation , but the migrations are not as extensive as with other large herbivores, such as the wildebeest . Apart from the annual hikes, there are also daily hikes that take place between the individual pastures, water points and rest areas.

Reproduction

Zebra mare with foal

Male cubs are sexually mature at four years of age, females at one and a half to two years. The first rutting phase is the reason for numerous male plains zebras to leave the bachelor groups and start their own herd. The plains zebra is ready to mate all year round, but an accumulation of mating occurs during the rainy season in summer. The rut lasts about two to nine days, the intermediate phases 17 to 24 days. The mating takes place mainly in the herd with the privilege of the dominant stallion. The birth interval is on average around 14 months, but the time interval is greater if the mother had previously given birth to a male foal.

After a gestation period of around 360 to 390 days - the average is 371 days - the zebra mare gives birth to a single foal weighing around 30 kg. The birth takes a total of about eight minutes and usually takes place at night, with the stallion watching from a distance of 10 to 50 m. After around eleven minutes the foal is already standing, after an average of an hour it is suckling milk for the first time. The bond between the mother and young animal is initially strong, the mother mare actively tries to keep herd members away from the foal, although in rare cases there can also be fights among female animals. If a new stallion takes over the herd, very young foals can be killed, but older young animals from around six months are not killed. Only in the subspecies of the Maneless Plains Zebra ( Equus quagga borensis ) such behavior has not yet been observed. The growth rate of the young is very high, the final size is reached after around a year, but the final weight only after three years. A foal needs milk for one to one and a half years. During the milk phase, the mare has to consume significantly more food to produce milk. With the birth of the next foal, the mother-young animal relationship usually dissolves. Female young animals then usually leave the herd and look for a new one. Due to the partly existing genetic relationship within the individual groups, the migratory movements of the female animals may not be very extensive during this phase. Males sometimes linger for a maximum of three years before moving away. Natural life expectancy is around 20 years, but plains zebras in captivity can live up to around 40 years.

Interactions with other animal species

Lions are the most important predators of the plains zebra

The predators of the plains zebra are leopards , cheetahs , spotted hyenas and wild dogs , but the main enemies are lions . Their main food is often zebras: In the Serengeti, 22% of all animals killed by lions are plains zebras, in the Kruger National Park around 16%. Lions kill stallions more often than mares. Spotted hyenas are the second most common group of predators after lions: zebras make up 15% of their diet. All other predators tend to hunt foals. The plains zebra defends itself against most predators, but not against lions, with kicks and bites.

Often, herds are formed with other herbivorous animal species, for example with wildebeest, lyre antelope , waterbuck and impala . Such large groups of different animal species usually form towards the end of the rainy season.

Parasites

Numerous parasites attack the plains zebra. The external ones mainly include lice . Tsetse flies , on the other hand, have not been detected in plains zebra, nor have they been infected with sleeping sickness . Endoparasites are known to many. These include above all suckers , tapeworms , thread worms , hookworms and lung worms . There are also stomach and nasal dassels . Babesia has also been observed, but African horse sickness and anthrax are particularly common . Studies have shown that the severity of the parasite infestation is directly related to the social structure of the animal and that higher-ranking members of a group are more rarely infested.

Systematics

Internal systematics of the genus Equus according to Jónsson et al. 2014
  Equus  
  caballines  

 Equus caballus


  non-caballines  


 Equus zebra


   

 Equus grevyi 


   

 Equus quagga




   

 Equus asinus


   

 Equus kiang


   

 Equus hemionus






Template: Klade / Maintenance / Style

The plains zebra is a member of the Equus genus and is one of today's modern horses. Within the genus Equus , it forms the group of stenonine or non-caballine horses together with the other zebra forms and the donkeys. This is defined by the characteristic shape of the lower molars. Furthermore, the plains zebra and the mountain zebra ( Equus zebra ) are placed in a separate sub-genus, Hippotigris . However, some DNA analyzes do not show a very close relationship to the mountain zebra, but a closer connection to the Asiatic donkey ( Equus hemionus ), more precisely to its subspecies of the onager, while another assumed an independent clade of the plains zebra compared to other more primitive horse representatives. Both studies indicate that the subgenus Hippotigris may not be monophyletic . In other studies, on the other hand, the zebras are closely related. What all studies have in common is that the wild horse ( Equus ferus ) forms the outer group.

Today there are six recent subspecies of the plains zebra:

  • Boehm's or Grant's zebra ( E. q. Boehmi Matschie , 1892); East Africa (Kenya, Tanzania, Uganda, Zambia)
  • Maned zebra ( E. q. Borensis Lönnberg , 1921); Southern Sudan, Southern Ethiopia, Northern Uganda, and Northern Kenya
  • Burchell's zebra ( E. q. Burchelli also E. q. Burchellii ( Gray , 1824)); northern South Africa, has been considered extinct since 1910, but is now equated with the Damara zebra ( E. q. antiquorum ). Since the older name has priority, burchelli applies .
  • Chapman's zebra ( E. q. Chapmani (also E. q. Chapmanni ) Layard , 1865); Zimbabwe, Botswana, Zambia
  • Crawshay's zebra ( E. q. Crawshayi De Winton , 1896); Northern Mozambique, Eastern Zambia (e.g. South Luangwa National Park ); the plains zebra subspecies with the densest stripes
  • Quagga ( E. q. Quagga Boddaert , 1785); South Africa, extinct since 1883. It was a light-legged, dark zebra with a medium brown base color. Only the head and neck were streaked to the withers.

The current classification was based on fur pattern and skull features and was made in 2004. Accordingly, the individual subspecies mostly show variations, especially in size and coat pattern. In general, there is a reduction in stripes and an increase in size from north to south. However, the transitions between the individual forms are fluid. Genetic studies of mini satellites and mitochondrial DNA in 17 populations of the five subspecies of the plains zebra living today also showed only minor differences between the individual subspecies, despite a large overall genetic variability. Further genetic studies from 2018 on the basis of plains zebras from the entire range did not provide sufficient agreement with the morphologically determined subspecies. Nine genetic populations can be distinguished, the Böhm zebra alone splits into three. In most genetic analyzes, the extinct quagga is closely linked to the other plains zebras and is now considered a separate subspecies. However, due to certain morphological differences, the quagga is still listed as a separate species by some specialists. The genetic difference between quaggas and the southern populations of the steppe zebra is around 1.5%, and that of the northern populations is 2.4%. Based on these values, the researchers assume that the separation of the quaggas from the southern steppe zebra subspecies occurred relatively late, namely during the icing maximum of the penultimate glacial period 290,000 to 120,000 years ago. In the Pleistocene , the now extinct subspecies E. q. mauritanicum in North Africa, and the Cape zebra ( Equus capensis ) is considered to be closely related to the plains zebra. All current populations of the plains zebra can be genetically traced back to a group of origin that lived in southern Africa about 367,000 years ago.

Quagga ( Equus quagga quagga )

Provided that the quagga is a subspecies of the plains zebra, the Dutch zoologist Pieter Boddaert is considered to be the first to describe the plains zebra. He introduced the quagga in 1785, and the plains zebra is then sold under the scientific name Equus quagga . With the recognition of the quaggas as an independent species, the English paleontologist John Edward Gray is the original descriptor of the plains zebra, who scientifically introduced the Burchell's zebra in 1824; the other subspecies would then have to be under Equus burchelli . These different names follow the rules of zoological nomenclature, according to which the older name is the valid one and the scientific name Equus quagga was used before the name Equus burchelli (originally described by Gray as Asinus burchellii ). The word "Quagga" goes back to a term used by the Khoisan peoples of southern Africa, which imitates the animals' characteristic greeting. The term is also used for the mountain zebra in other languages ​​of southern Africa, for example Afrikaans .

The first horses reached the African continent in the Pliocene . They belonged to the more original, stenonine group and formed the starting group for the zebras and the African wild ass. A possible ancestor of the plains zebra is Equus tabeti , which first appeared in North Africa in the late Pliocene and early Pleistocene and reached western Asia in the late Pleistocene . The horse shape is also seen as a possible ancestor of the African wild ass. Early occurrences of the plains zebra were reported from the Lower Pleistocene, for example from Kromdraai in South Africa with an age of around 2 million years. Other early finds are known from the Olduvai Gorge and Koobi Fora , each around 1.6 million years ago, and from Olorgesailie around 1 million years ago, all of East Africa. In East Africa the species was sometimes found together with Equus oldovayensis , in South Africa with Equus capensis . Both forms were originally considered to be close relatives of the Grevy's zebra, the latter being genetically similar to the plains zebra. The distribution of the plains zebra at that time roughly included its current occurrence. In the late Pleistocene, however, finds from E. q. mauretanicus also a representative of the zebra form from North Africa.

Plains zebra and man

Threat and protection

Plain zebra of the subspecies Maned Zebra ( Equus quagga borensis ) in the Dvůr Králové Zoo

Because of the hunt for meat and hides and the urban sprawl of their habitat by humans, plains zebras are far rarer today than they once were. Although they are still the most common of all horse species, three quarters of the population live in the national parks of Kenya and Tanzania, i.e. in a comparatively small area. Official estimates of the total population of the plains zebras in Africa assume around 660,000 animals. The most common is the subspecies E. q. boehmi , which makes up about 75% of the total population and is represented with more than 200,000 animals in the Serengeti - Masai Mara ecosystem, the largest population is the Serengeti with about 151,000 animals. Other wildlife sanctuaries where plains zebras occur are the Kruger , Pilanesberg , Etoscha , Chobe , Hwange , Kafue , South Luangwa , Ruaha , Tsavo East , Tsavo West and the Nairobi National Park . Other significant populations live in the Ngorongoro Crater, the Samburu National Reserve , the Hluhluwe Umfolozi Park and the Mkuze Game Reserve . While the populations of the subspecies Boehm's zebra and Burchell's zebra are relatively secure - the latter has meanwhile become extinct in its more southern distribution areas - the numbers of the subspecies Chapman, Crawshay and Manedless Zebra are likely to be threatened. The population in Angola is unclear, but experts believe that these have died out. The plains zebra is still extinct in Burundi and Lesotho . Observations in Tanzania showed a 20% decrease in the population in the 1990s and 2000s. An unusual settlement of plains zebras occurred in 1977 in the Calauit Game Preserve and Wildlife Sanctuary in the Philippines . The IUCN classifies the entire population of the plains zebra as least concern (“not endangered”).

There are several protection strategies coordinated by the Equid Specialist Group of the IUCN. These include resettlement and reintroduction of populations into former distribution areas, such as in the Transvaal and KwaZulu-Natal . Further priorities are increasing the number and frequency of observations in the field, a better risk assessment of the species and its subspecies, the maintenance and expansion of natural variability, a more comprehensive understanding of biological and ecological necessities and the development of alternative economic strategies for use, often in relation to Protected areas.

The Quagga Project

Quagga on display at the Natural History Museum in London

In addition to the preservation of the five recent subspecies of the plains zebra, there is a project to reverse or reproduce the quaggas exterminated by European settlers at the end of the 19th century. This project was started in 1986 by Reinhold Rau in South Africa after the quaggas DNA could be extracted for the first time, which led to the clarification of the relationship to the other zebras. To carry out the project, 19 plains zebras were selected from the wild population, mainly from the Etosha National Park and KwaZulu-Natal , which had relatively few stripes, and were brought to an area near Vrolijkheid in the South African province of Western Cape . This founder population produced 19 young animals, the first of which was born in 1988. In 2008, the total bred population comprised 89 plains zebras, kept in a dozen different locations and comprised at least 25 third generation foals. Since this third generation there has been a clear reduction in the stripes on the legs and in the back of the body and a tendency, albeit so far only slightly, to develop a brownish, horse-like body color, so that individual animals already show a clear similarity to the former Quaggas. The project is not without controversy, as some conservationists complain that only the phenotype of the quaggas is reconstructed. However, proponents argue that the quagga was ultimately determined based on its external characteristics.

Individual evidence

  1. ↑ a b c d e f g h i j k l m n o Peter Grubb: Equus burchelli. Mammalian Species 157, 1981, pp. 1-9
  2. ^ A b Véra Eisenmann and C. de Giuli: Caractères distinctifs entre vrais Zèbres (Equus zebra) et Zèbres de Chapman (Equus burchelli antiquorum) d'après l'étude de 60 têtes osseuses. Mammalia 38, 1974, pp. 509-543
  3. ↑ a b Ann Forstén: Mitochondrial DNA time-table and the evolution of Equus: comparison of molecular and paleontological evidence. Annales Zoologici Fennici 28, 1992, pp. 301-309
  4. ↑ a b c d M. A. Hack and Eline Lorenzen: Equus quagga. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.1. ( [1] ), last accessed on August 20, 2012
  5. ↑ a b Wenfei Tong, Beth Shapiro and Daniel I. Rubenstein: Genetic relatedness in two-tiered plains zebra societies suggests that females choose to associate with kin. Behavior 152 (15), 2015, pp. 2059-2078, doi: 10.1163 / 1568539X-00003314
  6. ^ A b Heather I. Simpson, Sean A. Rands and Christine J. Nicol: Social structure, vigilance and behavior of plains zebra (Equus burchellii): a 5-year case study of individuals living on a managed wildlife reserve. Acta Theriologica 57, 2012, pp. 111-120
  7. ↑ Florian Barnier, Sophie Grange, Andre Ganswindt, Hlengisizwe Ncube and Patrick Duncan: Inter-birth interval in zebras is longer following the birth of male foals than after female foals. Acta Oecologica 42, 2012, pp. 11-15
  8. ^ Ilya R. Fischhoff, Siva R. Sundaresan, Heather M. Larkin, Marie-Jeanne Sellier, Justine E. Cordingley and Daniel I. Rubenstein: A rare fight in female plains zebra. Journal of Ethology 28, 2010, pp. 201-205
  9. ↑ January Pluháček and Ludek Bartos: Further evidence for male infanticide and feticide in captive plains zebra, Equus burchelli. Folia Zoologica 54 (3), 2005, pp. 258-262
  10. Jump up ↑ Jan Pluhaček, Luděk Bartoš and Jitka Víchová: Variation in incidence of male infanticide within subspecies of Plains zebra (Equus burchelli). Journal of Mammalogy 87 (1), 2005, pp. 35-40
  11. ^ C. Dustin Becker and Joshua R. Ginsberg, Mother-infant behavior of wild Grevy's zebra: adaptations for survival in semidesert East Africa. Animal Behavior 40, 1990, pp. 1111-1118.
  12. ^ P. Neuhaus and KE Ruckstuhl: The link between sexual dimorphism, activity budgets, and group cohesion: the case of the plains zebra (Equus burchelli). Canadian Journal of Zoology 80, 2002, pp. 1437-1441
  13. ↑ RC Krecek, FS Malan, RK Reinecke and V. de Vos: Nematode parasites from Burchell's zebras in South Africa. Journal of Wildlife Deseases 23 (3), 1987, pp. 404-411
  14. ↑ Elizabeth N. Wambwa, WO Ogara and Dennis Mudakha: A comparative study of gastrointestinal parasites between ranched and free ranging Burchell's zebra (Equus burchelli antiquorum) in Isiolo district, Kenya. Journal of Veterinarian Sciences 5 (3), 2004, pp. 215-220
  15. ↑ MC Fugazzola and L. Stancampiano: Host social rank and parasites: Plains zebra (Equus quagga) and intestinal helminths in Uganda. Veterinary Parasitology 188, 2012, pp. 115-119
  16. ↑ a b Hákon Jónsson, Mikkel Schubert, Andaine Seguin-Orlando, Aurélien Ginolhac, Lillian Petersen, Matteo Fumagallic, Anders Albrechtsen, Bent Petersen, Thorfinn S. Korneliussen, Julia T. Vilstrup, Teri Lear, Jennifer Leigh Myka, Judith Lundquist, Donald C. Miller, Ahmed H. Alfarhan, Saleh A. Alquraishi, Khaled AS Al-Rasheid, Julia Stagegaard, Günter Strauss, Mads Frost Bertelsen, Thomas Sicherheitsitz-Ponten, Douglas F. Antczak, Ernest Bailey, Rasmus Nielsen, Eske Willerslev and Ludovic Orlando: Speciation with gene flow in equids despite extensive chromosomal plasticity. PNAS 111 (52), 2014, pp. 18655-18660
  17. ↑ a b c Samantha A. Price and Olaf RP Bininda-Emonds: A comprehensive phylogeny of extant horses, rhinos and tapirs (Perissodactyla) through data combination. Zoosystematics and Evolution 85 (2), 2009, pp. 277-292
  18. ↑ a b c d Ludovic Orlando, Jessica L. Metcalf, Maria T. Alberdi, Miguel Telles-Antunes, Dominique Bonjean, Marcel Otte, Fabiana Martin, Véra Eisenmann, Marjan Mashkour, Flavia Morello, Jose L. Prado, Rodolfo Salas-Gismondi , Bruce J. Shockey, Patrick J. Wrinn, Sergei K. Vasil'ev, Nikolai D. Ovodov, Michael I. Cherry Blair Hopwood, Dean Male, Jeremy J. Austin, Catherine Hänni and Alan Cooper: Revising the recent evolutionary history of equids using ancient DNA. PNAS 106, 2009, pp. 21754-21759
  19. ↑ Julia T. Vilstrup, Andaine Seguin-Orlando, Mathias Stiller, Aurelien Ginolhac, Maanasa Raghavan, Sandra CA Nielsen, Jacobo Weinstock, Duane Froese, Sergei K. Vasiliev, Nikolai D. Ovodov, Joel Clary, Kristofer M. Helgen, Robert C. Fleischer, Alan Cooper, Beth Shapiro, and Ludovic Orlando: Mitochondrial Phylogenomics of Modern and Ancient Equids. PlosONE 8 (2), 2013, p. E55950.
  20. ^ A b c Colin P. Groves and CH Bell: New investigations on the taxonomy of the zebras genus Equus, subgenus Hippotigris. Mammalian Biology 69 (3), 2004, pp. 182-196
  21. ↑ a b Eline D. Lorenzen, Peter Arctander and Hans R. Siegismund: High variation and very low differentiation in wide ranging plains zebra (Equus quagga): insights from mtDNA and microsatellites . Molecular Ecology 17 (12), 2008, pp. 2812-2824
  22. ↑ a b c Casper-Emil T. Pedersen, Anders Albrechtsen, Paul D. Etter, Eric A. Johnson, Ludovic Orlando, Lounes Chikhi, Hans R. Siegismund and Rasmus Heller: A southern African origin and cryptic structure in the highly mobile plains zebra. Nature Ecology and Evolution 2, 2018, pp. 491-498, doi: 10.1038 / s41559-017-0453-7
  23. ↑ Jennifer A. Leonard, Nadin Rohland, Scott Glaberman, Robert C. Fleischer, Adalgisa Caccone and Michael Hofreiter: A rapid loss of stripes: the evolutionary history of the extinct quagga. Biological Letters 1, 2005, pp. 291-295
  24. ^ A b Martha I. Grinder, Paul R. Krausman and Robert S. Hoffmann. Equus asinus. Mammalian Species 794, 2006, pp. 1-9
  25. ^ The Quagga Project: Origin of the name "Quagga". ( [2] ); Internet presentation of the project, last accessed on May 15, 2019
  26. ^ LB Penzhorn: Equus zebra. Mammalian Species 314, 1988, pp. 1-7
  27. ↑ Sally Christine Reynolds: Mammalian body size changes and Plio-Pleistocene environmental shifts: implications for understanding hominin evolution in eastern and southern Africa. Journal of Human Evolution 53, 2007, pp. 528-548
  28. ^ CS Churcher: Equus grevyi. Mammalian Species No. 453, 1993, pp. 1-9
  29. ^ Palawan Council for Sustainable Development: The Calauit Game Preserve and Wildlife Sanctuary. ( [3] )
  30. ^ Mace A. Hack, Rod East and Dan I. Rubenstein: Status and Action Plan for the Plains zebra (Equus burchellii). In: PD Moehlman (Ed.): Equids: Zebras, Asses, and Horses: Status Survey and Conservation Action Plan. IUCN / SCC Equid Specialist Group, IUCN (The World Conservation Union). Gland (Switzerland) and Cambridge, 2002, pp. 43–60
  31. ↑ Equid Specialist Group: Plains zebra. ( [4] )
  32. ↑ Russel Higuchi, Barbara Bowman, Mary Freiberger, Oliver A. Ryder and Allan C. Wilson: DNA sequences from the quagga, an extinct member of the horse family. Nature 312 (15), 1984, pp. 282-284
  33. ^ Rochelle Parsons, Colleen Aldous-Mycock and Michael R. Perrin: A genetic index for stripe-pattern reduction in the zebra: the quagga project. South African Journal of Wildlife Research 37 (2), 2007, pp. 105-116
  34. ↑ Eric H. Harley, Michael H. Knight, Craig Lardner, Bernard Wooding, and Michael Gregor: The Quagga Project: Progress Over 20 Years of Selective Breeding. South African Journal of Wildlife Research 39 (2), 2009, pp. 155-163
  35. ↑ The Quagga Project ( [5] ); Internet presentation of the project, last accessed on May 15, 2019

Web links

Commons : plains zebra  - album with pictures, videos and audio files