ABOUT THE PLAINS ZEBRA of AFRICA
The Plains Zebra also known as Equus quagga initially referred to as the Burchell’s Zebra or Common Zebra is noted to be the commonest and the widely spread Zebra Species that stretch from Ethiopia through the East of Africa including Uganda to the southern countries of Botswana and the east of South Africa. Though the Plains Zebra remains the common species in most of the game reserves, it is also threatened by a range of man’s activities including hunting for meat and hide, competition for pasture with the livestock and habitat encroachment.
The Plains Zebra’s habitat is scattered but extends most to the eastern and south of Africa generally in the Southern Sahara. The habitat of the plains Zebra is mostly open grasslands including savannah woodlands in tropical and temperate environments. These Zebras avoid the desert, permanent wetlands, dense rain forests and tend to keep close to water sources about thirty (30) Kilometers.
The plains Zebra are greatly Social Species that tend to form harems with a single stallion, a range of mares and the newly born offspring. The Bachelor groups also tend to exist. These groups at times come together hence forming herds. The Plains Zebras keep watch of the predators other than attempts to hide away from them. They react by barking or snorting when they are confronted by a predator. The stallion can attack the predators like hyenas, dogs and leopards in order to defend his harem. It can be noted that the Species of Plains Zebra is considered stable though in some destinations like Tanzania, the numbers have reduced sharply.
Regarding the taxonomy, there has been disagreement among the taxonomists on how to clearly do the Zebra Species classification. It is noted that plains Zebra and the Mountain Zebra originate from the Sub genus Hippotigris while the Grévy’s zebra is the only Species of subgenus Dolichohippus. This has resulted from the fact of Grévy’s zebra looking like the sub genus Asinus whereas the mountain zebra and mountain Zebra have horse like structures. The three animals fall under the genus Equus like other equids that are still living. However other issues have emerged. The current phylogenetic evidence notes that the Grévy’s zebras and mountain Zebras have to be categorized with asses and the donkeys in the line that is distant from the plains Zebra. In regions where the plains Zebra are close to the Grévy’s zebras, it is not strange to find the two thriving in a single herd and at times fertile hybrids occur. In the captivity, the mountain zebras have been crossed with the plain zebras and the hybrid offsprings do not have dewlap and resemble plains Zebra apart from their larger ears and the pattern of their hind quarters.
Regarding the Subspecies, there are six sub species which are apparently recognized according to the findings of Bell and Groves in the year 2004 whose research was published in the Mammalian Biology Journal.
These include; the Quagga also known as Equus quagga quagga as noted by Boddaert in 1785, Burchell’s zebra also known as Equus quagga burchellii noted by Gray in 1824, Grant’s zebra also known as Equus quagga boehmi as noted by Matschie in1892, Maneless zebra also known as Equus quagga borensis as noted by Lönnberg in 1921, Chapman’s zebra also known as Equus quagga chapmani as noted by Layard in 1865, Crawshay’s zebra also known as Equus quagga crawshayi as noted by De Winton in 1896 and eventually Selous’ zebra also referred to as Equus quagga selousi as noted by Pocock in 1897.
Originally the Quagga was noted as separate species – Equus quagga in the year 1778 and over 50 years that followed a range of other Zebra were noted by explorers and naturalists. Basing on the fact that no two zebras are alike – the variation in patterns of Zebra coats, the taxonomists had nothing to zero on but to be left with a wide number of described “species” with difficulty on ascertaining the true Species among those along with sub species or just their natural variants. It should be noted that the quagga was the initial extinct creature whose DNA had been studied. The most recent study by the Smithsonian Institution demonstrates that quagga was not a distinct species at all but separated from the plains zebra between 120,000 and 290,000 years ago and proposes that it would have been named Equus burchellii quagga but since the rules of biological nomenclature give the first name the priority in cases where there are alternative or two names for single species, the new proposal would not take effect. Since the quagga was described around 30 years earlier other than Burchell’s Zebra, it appears that the right references are E. quagga quagga for the quagga while for the Plains Zebra is E. quagga burchellii until the “Equus burchellii” is declared officially in the nomen conservandum.
Regarding the Physical description, it can be noted that the plains Zebra is a mid-sized and averagely smaller than the two other Species of Zebra and features thick body and short legs. There is difference in size considering the animal’s sub species and conditions. The adults both male and female rise form 1.1m to 1.45m high at the shoulder level and stretch from 2.17m to 2.46 m in length not considering the 47 to 56cm tail. They weigh between 175kg to 385kg. The Male Zebras can stretch to 10% in weight more than the females.
Just like other Zebras, the plains Zebras are boldly striped aligned in black and white with no two individuals having the same pattern. They feature dark or black muzzles and the natal coat for the plains zebra is brown and white. They feature vertical stripes on the front of the body which tend towards horizontal format to the hind body quarters. The northern Zebras feature narrower and clearer stripping while the southern populations feature diverse but few counts of stripping on the under parts, the hindquarters and the legs. The Southern Zebra populations feature brown shadow stripes in between the white and black coloring which are poorly expressed or absent in the northern Zebras. The embryological evidence indicates that the background color of the Zebra is black and the white is just an addition. The quagga which is now extinct is noted to have had plain brown hindquarters. A range of mutation among the Zebras occurs from mostly white to mostly black. The cases of albino zebras have been noted to exist in Mount Kenya forests.
Regarding the function of stripes, the pattern of stripes of the Zebra is unique among the sympatric ungulates and one of the importances of the stripes is to offer a crypsis for the animal in tall grass or in the dappled shade beneath bushes and trees. It should be noted that Zebras do not hide from the predators but are noisy and active. The other suggested use of the stripes is the motion camouflage and these stripes confuse the eyes of the predator when the Zebra is in motion. The predator finds it hard to judge the size, direction and the distance of the Zebra that is in target. This was supported during the 2014 study stating that the Zebra Stripes might confuse predators, observers, and the biting insects through two illusions namely the wagon wheel effect where the perceived motion is inverted and then the barber pole illusion where the perceived motion is in wrong direction. The third proposed use of stripes is that the predator finds it hard to single out an individual chase after attacking a herd of them.
It is further noted that what can be termed as the best explanation for the stripes is serving the social function. The individual Zebras recognize one another by the stripping patterns. Other suggestions indicate that the stripes might serve as visual cues for grooming, helping the zebra groups to keep together as they flee and discouraging biting flies. The issue of the biting flies is justified in a way that the stripes polarize light which in turn discourage biting flies. The 2015 study indicate that the temperature of the environment has got an effect of the pattern of the Zebra stripes and suggests that the stripes could be associated with thermo regulation
Regarding the ecology, the plain Zebras depend on water and as a result, its range in Africa stops in South Sudan and Southern Ethiopia to the north and then extends southwards. They are noted to have got extinct from Lesotho and Burundi and noted to might have existed in Algeria in the Neolithic era. Apparently, the plains Zebra generally thrive in the open grasslands and savannah woodlands though they can be traced in a rage of habitats including the temperate and tropical ones. The Plain Zebras are generally not occurring in deserts, permanent wetlands and the dense forest covers. They can thrive on raised altitudes such as 4,300 m above sea level on Mount Kenya. The Plains Zebras depend on rainfall for water and food (pasture) and as a result, they migrate to places with such offerings. The Zebras can move up to 1,100km in search of food. The Plains Zebra are generally water dependent and would keep in 25 – 30km from the water source.
Regarding their Diet, the diet of the Plains Zebra is noted to be 92% grass and then 3% shrubs. The Plains Zebra consumes a wide range of grasses with preference to young and fresh grass where available. The Zebras also browse in shoots and leaves from time to time. The Plains Zebra ranges in extended landscapes including the woodland ecosystems and it is noted to be the first grazer to appear is a well vegetated area. The Zebras have got simple stomachs and they use the hindgut fermentation that allows them to digest and assimilate considerable quantities of forage in the 24 hour period. The Plains Zebras are considered to be less selective when it comes to grazing though they do not spend a lot of time grazing. It is noted that the Zebras are primary / pioneer grazers and then pave way for the specialized grazers like the blue wildebeests and the Thomson’s gazelles which thrive on shorter and highly nutritious grasses.
About their predation, the Plains Zebras are more prone to attacks from the lions and the Spotted Hyenas not forgetting the Nile crocodiles while attempting to cross rivers during migrations. Other predators include; the cheetah, wild dogs not forgetting leopards and these usually attack the foals. The Olive Baboon might prey on foals too with no any threat to adults. The Zebras also have the capacity to defend themselves through strong bites and more powerful kicks that are enough to put the predator to rest. For larger predators, the Zebras try to out run them and tend to stand their ground with the minor predators.
Regarding the interactions with other grazers, the Plains Zebra herds can mix up and join other grazers during migrations especially the Wildebeests though with occasional aggressions.
In addition to their social structure, the Plains Zebra is considerably social and normally form small family units called harems that consist of a single stallion, the offspring and a range of mares. The adult composition of a harem is highly stable and tends to keep together for months to years. The male groups also referred to as Bachelors also exist and comprise of 2 – 15 individuals with an age based hierarchy headed by a young male. These males stay in their respective groups until it their right time to form a harem. The Bachelor Zebras do a lot to prepare for their future roles including play fights and challenge / greeting rituals forming most of their activities. The bachelor groups and multiple harems come together to form herds though Plains Zebra are unusual to forming these groups. It can be noted that the Stallions tend to form the harems and then expand on them by confiscating young mares from their natal harems. At the time when the mare reaches the sexual maturity point, it demonstrates estrous posture that would definitely attract the nearby stallions including the harem leaders and the bachelors. Her family head / stallion which is most likely to be her father would definitely chase off other stallions and at times enter into fighting to stop them from abducting her. The young mare is even isolated from her natal harem and the fight for it continues until the estrous cycle is done. It is unusual for the initial mare abductor to keep her for a long period. When the mare eventually ovulates, the stallion / male that impregnates her, takes her for life and the mare becomes a permanent member of the new harem. It should be noted that that the female estrous posture is less noticeable to the outside males as she grows older. This makes competition among the old females dormant compared to the young. The Mares live in hierarchy and the alpha female is the one that mates first with the stallion and she also leads the group. In situation where the new mares have been added to the group, they are met with ultimate hostility from other mares. Therefore, the stallion has to commit himself to defending of the mare until the aggression normalizes. The new mares take the lowest ranks however even for the exiting members; the females that lose a degree of fitness or grow weak have to drop in the ranking. It should be noted that the harem composition remains intact even when a new stallion takes over. The Zebras attempt to strengthen the social cohesion through grooming. The harem members nip and scrape along the neck, the back and the shoulders using their lips and teeth. The foals and mothers do groom often and they are followed by siblings. The grooming aspect depicts social status and reduces the aggressive behavior.
The stallion is committed to defending his harem from other males. A stallion when challenged, it releases a warning to the attacker by rubbing nose or shoulder with him and if the warning is not respected, a fight automatically breaks out. It should be noted the fights of the Zebras tend to be more violent with the animals biting one another’s legs, necks or heads; wrestling up to the ground and kicking occasionally. At times, the stallion can lie on the ground as if it is surrendering the fight but once the other male loosens up, the one on the ground would strike again and the fight resumes. Most of the Zebra fights occur when the mares are in the estrous. However, when the stallion is healthy, it always not challenged but for the unhealthy stallions, their harems are usually taken over even with no fighting.
Regarding communication, there are counts of six various calls that the plains Zebra is noted to make. The most distinct is the high pitched call made as “a-ha, a-ha, a-ha” or “kwa-ha, kaw-ha, ha, ha”. In cases of predator sighting, the Zebra makes a two syllable alarm call and loud snort is made when moving in cover of potential danger. In times of contentment, the Zebra will make a more drawn out snort. The Males make a short high pitched squeal when subjected to hurt while the foals emit a drawn out wail when experiencing distress. The Zebras feature two main facial expressions where by one is for greeting and the ears are sticking up and forward directed while the second is for threatening and the ears are pointed down.
Regarding Reproduction, the stallion mates with all the mares in his harem and the mares give to one foal after twelve months and the peak for giving birth is rainy season. The mare nurses her foal up to one year and it can be noted that the stallion in generally not friendly to the foals that do not belong to him. It also possible for Zebras to practice infanticide and feticide and this also occur in captive animals. Zebras just like the horses can suckle shortly after being born, stand, walk or run from danger. The mare keeps the foal away from other mares and the stallion after birth. In the harem, the foal enjoys the same rank as the mother. The Plain Zebra foals are protected by the respective mother and the stallion not forgetting other mares in the group. However, despite all this protection, close to 50% of the foals are taken by the predators, starvation and disease every year. The relationship between the male foals and their mothers tend to fade up easily and thus the young stallion looks for other young stallions for company while the young mares can stay in the harem up to time of abduction.
Regarding the predator behavior, the plains Zebras protect themselves by retreating in open grasslands that offer them good visibility even at night. When the Zebras sleep or forage, one Zebra keeps on watch and upon spotting the Predator, he makes a warning sound to the entire group for action. In case of hyena or wild dog attack, the harem stays together tightly to protect the target especially the foals and the stallion will attack the predators. However, the hyenas tend to dodge the stallion and concentrate on the herd. The mares also react aggressively when their foals are threatened. And unlike the case of wildebeest, the Zebras do not opt for water while escaping from hyenas. The Zebras can only be safe from lions by outpacing them since lions do not have a lot of endurance in running like wild dogs or hyenas. The leopards and cheetahs are great threats to foals but an adult Zebra can drive them away.
Regarding conservation, the Plains Zebra populations are considerably stable with no major threat that would result into immeasurable decline. The Plains Zebras can be traced in a number of protected areas including Serengeti National Pak in Tanzania, Etosha National Park in Namibia, Masaai Mara and Tsavo National Parks in Kenya an Kruger National Park in South Africa. There are also some stable populations thriving outside the protected areas. They are given at 750,000 populations and quagga – one of the sub species is apparently extinct. The Zebra populations have considerable decreased in Tanzania at a rate of 20% from 1990s to the mid-2000s. The major threat of the Zebras includes hunting for meat and hide, habitat loss to human encroachment, and competition for food with the livestock. The northern populations are threatened by poaching while the southern populations are threatened by habitat loss. The civil wars on the sub Saharan Africa including Rwanda, Ethiopia, Somalia and Uganda have also contributed to significant population loss. In countries like Burundi, the Zebras are considered extinct. In countries like Angola where civil war has existed for over 25 years, the wildlife populations have suffered considerably including those of plain Zebras. Nevertheless, it should be noted that plains Zebra appear as protected in a broad scope of their range and they are noted to be among the impressive safari products increasingly featured in many packages including Uganda safaris and tours.
Regarding Culture, the Zebras are admired in a range of African Cultures as beauty symbols. In Uganda, the Karamajong tribe has their women painted in Zebra Stripes as they act like them while dancing. In South Africa, the Dube tribe has Zebra as their totem. In Botswana, the Zebras have gone ahead to appear on the country’s Court of Arms. This justifies the traditional attachment that Africans have with the Zebras.