Colours of Wildlife: Common Zebra
Created | Updated Oct 1, 2017
Common Zebra
Willem is a wildlife artist based in South Africa. He says "My aim is simply to express the beauty and wonder that is in Nature, and to heighten people's appreciation of plants, animals and the wilderness. Not everything I paint is African! Though I've never been there, I'm also fascinated by Asia and I've done paintings of Asian rhinos and birds as well. I may in future do some of European, Australian and American species too. I'm fascinated by wild things from all over the world! I mainly paint in watercolours. . . but actually many media including 'digital' paintings with the computer!"
At last! Here you have a Common Zebra, also known as a Burchell's Zebra, Equus quagga or Equus burchellii. The confusion is based on the difficulty of distinguishing this from the sadly extinct Quagga, which may or may not have been a different species than the surviving zebras. More on the quagga later. For now, common zebras are what you would find on the plains of Southern and Eastern Africa, only the dry horn of Africa hosting the Grevy's zebra and the mountains of southwestern Africa suiting the Mountain zebra. Along with the Wild Ass, these are the only remaining naturally wild equids of Africa. Common zebras reach a shoulder height of 1.4 m/4'4" and a weight of 320 kg/700 lbs.
Equid Evolution
I've spoken of the fascinating evolutionary history of horses before, but let me do so again. Horses originated in North America, the earliest kinds having lived over 55 million years ago. They were small, the size of smallish dogs, and lived in forests, where they browsed on leaves and herbs. With time, horses became bigger, but by no means was their evolution linear, that is to say in a straight line. There remained a diversity of browsing types, but many kinds evolved to live on the open plains, eating the plentiful grass. Forest-living horses got bigger too, and also had a reduction in toe number, mostly to three toes, but still browsed leaves; plains-dwelling horses experienced a reduction of toes to one – a few kinds still had three toes but the outer toes having become small and sometimes not even touching the ground. Horses remained typical New World mammals for much of their evolution, occurring over North as well as South America. Forest-dwelling horses soon faced fierce competition from, mainly, deer, and went extinct, but grazing, plains-dwelling horses remained very successful. Their advantages consisted in very efficient digestion, enabling them to subsist on coarse, low-nutrient plains grasses, and physical speed and endurance, enabling them to travel great distances in search of food and water. Horses moved from North America into Asia and Europe comparatively recently (about three million years ago) and from there to Africa. Only the most successful horse species made it to Africa. Because these (zebras) are all striped, it is thought that many or even most of the extinct horse species were also striped – it might even be the default pattern for horses, with only the wild asses and the ancestors of domestic horses having lost these stripes for various reasons. As it is, several species of horses, striped or not, lived in the Americas, Asia and Europe until very recently. Then humans arrived on the scene, and quickly exterminated the majority of wild horse species. Even the wild ancestors of the horses they domesticated, no longer exist, with only the Przewalski's Horse, a relative of these ancestors, still (only just) surviving. In the Americas, all wild horses were exterminated, the group only returning with the Spanish conquistadores.
In Africa, horses flourished, but even so, were hard pressed by humans. Wild asses were exterminated from the majority of their desert range; the original quagga of South Africa was driven extinct; the Mountain Zebra of the Cape almost suffered the same fate; and the common zebra's range decreased greatly. Once having been found even in Algeria in North Africa, it now occurs only in southern and eastern sub-Saharan Africa. Zebras were driven out of areas where people wanted to farm or herd cattle. Today they mainly exist in large game parks or nature reserves. Fortunately, the common zebra does indeed remain common where it is protected. In South Africa, they're now found in many small reserves and game farms. (I include a photo of myself encountering a tame zebra in a reserve in the Waterberg Mountain area.)
A Life in Stripes
Where they're allowed enough room to roam, zebras indeed enjoy roaming. The core groups in which zebras live, are harems or family groups, and bachelor herds. A typical harem consists of a few mares presided over by a single dominant stallion. They're joined by their offspring, both fillies and young colts, but when the colts mature to stallions, they're driven away and then either remain single, or form small bachelor herds. Stallions from these sometimes try to drive away a dominant male to take over his harem, but they don't often succeed.
Aside from this, common zebras are not strictly territorial. Different herds mingle and share the same territory, and as I've said, often cover much ground seeking food, both in daily movements and seasonal migrations. They're typically after fresh grass as well as drinking water. Though they can indeed subsist on tough, dry grass, they prefer the moist, lush kind such as regrows after having been grazed, or shortly after the first seasonal rains, or growing after a veld fire. Zebras tolerate regions with some trees, provided there's still much open grassland to feed on. They will do a little bit of browsing on herbs and shrubs. They've even been seen eating scorched leaves and twigs after a fire.
But they are particular about water. They can't properly digest all that rough stuff without drinking a bit in between. During the rainy season, water is usually easy to access in the form of temporary pools and pans, but in the dry season, the zebras retire to large rivers where there are permanent drinking pools, or to large lakes. Because they can move quickly and over long distances, they are able to range quite far away from these, so long as they can return to the precious wet stuff each day. But for some reason, they're not good swimmers, and avoid crossing rivers if they can. Also, they prefer taking dust baths to immersing their bodies.
When drinking at a large river or lake, zebras are very wary. They might get attacked by crocodiles or by ambushing lions or hyenas. They're aided in perceiving threats by their excellent sight and hearing. On the plains, they often occur together with wildebeests and other game, which they also aid by spotting predators and uttering barking alarm calls. Once a predator is spotted, the zebra's speed and endurance aid them in escaping. They can also defend themselves by kicking or biting, and zebras have been recorded killing adult hyenas. Zebra foals, however, suffer much from predation, more than from disease or starvation.
Zebra stripes remain a mystery. It has been conjectured that the stripes break out the zebra's outlines, making them harder to spot or to fix on by predators, but frankly I think this underestimates the senses of the predators. Lions do catch a lot of zebras, especially young ones. The stripes have also been linked to temperature regulation, and to dissuading parasitic insects, but again this is still conjectural. Lastly the stripes may feature in recognition and bonding amongst the zebras themselves, and for this there's fairly strong evidence and argumentation. You'll know, I hope, that the stripe pattern of every individual zebra is unique. It's even the case that the stripes are not symmetrical – the left half of the zebra is not a mirror copy of the right, but differs. So, zebras can use their stripes to identify each other. This makes it especially easy for foals to recognize and bonds with their moms – and vice versa – but also helps members of a herd to know each other. But more than that, the zebras themselves may find the stripes attractive! And just look at a zebra: those stripes are surely striking and dashing. Though I am familiar with zebras and so may tend to find them more ho-hum and usual than perhaps someone from Britain or the USA would, even I must admit those stripes are pretty wild, definitely among the topmost extravagant and flamboyant decorations found on any land mammals. So probably the zebras find themselves beautiful! This may help to hold herds together against the strong aggressive tendencies of the individual members. Zebras in herds to seem to like each other, and frequently nibble at each other's manes and short body fur.
Then there's the matter of vocalisations. Zebras are quite vocal, which you'll come to know if you ever visit one of Africa's great game reserves such as the Serengeti or the Kruger National Park. The typical call is a two or three-part whinny or bark, quite musical when compared to the neighing of horses or the braying of donkeys. This call is where the extinct quagga got its name from, though I don't consider the word 'quagga' to really capture the sound. This call is mostly uttered by the dominant male, and helps the dispersed members of the herd to focus. Any members who get lost, will appear distressed and perk their ears, while the male, realising that someone is missing, will also search and call loudly, until the lost member is found again.
Zebra foals are born mostly during the rainy season, which is summer in the regions of Africa where they occur. The mare carries her single foal for a year or slightly more; it is born open-eyed and alert, with long legs allowing it to run with the herd from the start. The bond between mother and child is extremely strong, and she'll even chase other zebras away from it. But when the zebras are moving, the entire herd will let the mother and her foal run in front and protect them. The dominant stallion typically guards the rear of the group on the move. Foals are weaned at around 11 months. They are sexually mature at 18 months to three years age, and can reach the age of forty years.
The Sad Case of the Quagga
Let's discuss that old creature called the Quagga, which I mentioned briefly above. When Dutch settlers came to the Cape in the seventeenth century, they found a number of different kinds of horsey things – and didn't go to much trouble to distinguish them, calling them 'horses' or 'ponies' or 'donkeys' or 'mules', and describing them so fancifully that their descriptions are sometimes hard to credit. Only by the late eighteenth century was there some rigour in distinguishing the different kinds. In dry mountainous regions was found the Cape Mountain Zebra; on the dry plains of the Karoo south of the Orange River was found the Quagga; in the lush grasslands and savannahs to the north of this was found the proper Common Zebra, often called Burchell's Zebra. The quagga differed from both the other kinds of zebra, by being incompletely striped. Only its head, neck and shoulders bore vivid stripes, the rear parts of its body being uniform reddish-brown with sometimes only faint striping or speckling; its front and hind legs were whitish down to the hooves. Its belly, buttocks and tail also tended to be white. In behaviour, these were similar to the plains zebras, also living on plains and in herds. They were massively impacted by humans: not so much by hunting, though the farmers did shoot many, but more, they were driven from their range when the farmers brought in cattle, goats and sheep. The dry and barren Karroo was never able to sustain many large grazers; sheep and goats so denuded the naturally sparse grass that the quaggas soon had nothing to sustain them. By the nineteenth century they were already dwindling, and by the end of that century, they had disappeared. The last quaggas died in European zoos; just a single photo of a living specimen is known, and today only a handful of skins, stuffed specimens and skeletons remain as relicts of this once-abundant critter.
Because quaggas disappeared pretty much before science even properly knew about them, they've not been studied much, and thus the difficulty of deciding whether they constituted a fully-separate species, or whether they were just a local, southern form of the abundant common zebra. Their partly-striped coats seem to distinguish them from all other African equines apart from the wild ass, but in shape, habit and call they're very similar to plains zebras. Genetics – from what sparse physical samples remain of them – seem to closely ally them with common zebras. Indeed, common zebras do differ in the degree of striping, and here in South Africa you do on occasion see a zebra with indistinct stripes on its legs and/or hindquarters, some even having largely unstriped legs, bellies and buttocks. Maybe the quagga was just the end of this trend. If indeed this is the case, there is a possibility that the quagga can be 'bred back' from common zebras, and there is a project in South Africa to do just that! They're selecting zebras with minimal striping and breeding these with each other. But some respect for the geographic, genetic and historical uniqueness of the quagga should prompt us to not be quick to call these true quaggas – instead, they're at best, artificially-bred quagga-forms or 'quaggoids'. But if they're successful and can cope, they can indeed become wild creatures and in time come to evolve on their own and constitute a new, natural form in their own right. Not actual quaggas – those are gone forever – but something new, and true.
