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Burchell’s zebra - When the stripes become blurred

Avatar of inke inke - 16. September 2016 - Discover Namibia

A black zebra and normal members of the species grazing peacefully side by side. Photo: Dirk Heinrich

Many years ago a tourist from South Africa told nature conservation officials in the Etosha National Park that instead of Blacky he had spotted “die ander merrie” (the other mare). Blacky was almost completely black and at that stage probably the best known plains zebra in the park. But there was another zebra whose black stripes were blurred, except for the usual white underbelly and parts of the legs. After the excited visitor from the Transvaal had reported his sighting of the “ander merrie”, this second mare was named Annemarie because the English-speaking nature conservation official was a little lost with Afrikaans.

For several years Blacky and Annemarie caused excitement among tourists who spotted them on the vast plains of the park. The two unusual Burchell’s zebras, in the vernacular referred to as plains zebra, unwittingly gave away quite a few secrets about the migration routes of their family groups as their conspicuous dark coats were so easy to spot among the black and white stripes of the fellow members of their species. The two black mares and their family groups and other herds were seen far west of Okaukuejo in an area known as Grootvlaktes, or the vast plains.

One day in the middle of the rainy season several tourists and nature conservation officials were lucky enough to spot an almost black foal in the green scenery. The young zebra with blurred stripes was then seen repeatedly at the Klein Namutoni waterhole. Even scientists started to show an interest in the black zebras of Etosha. The foal, however, disappeared one day and was never seen again. It is quite likely that it fell prey to lion or spotted hyena.  

As yet there is no scientific explanation for melanism in only a few individual zebras. Perhaps the development of dark-coloured pigment is caused by hereditary genes. Or perhaps the cells (melanocytes) which are responsible for dark pigments are damaged, resulting in increased production.

Blacky and Annemarie are no longer around, even though Burchell’s zebras (Equus Burchelli) live up to 25 years old. Three new “black” zebras have taken their place in Etosha National Park but they haven’t been given names and do not cause quite as much excitement as Blacky and Annemarie did in their day.

However not only “black” zebras stand out from the rest of the herd. Each and every zebra can be distinguished by its stripe pattern by specialists equipped with suitable computer programmes. The patterns of zebra stripes are as different as fingerprints and ordinary observers will definitely not be able to recognise a specific zebra by its stripes. 

The black and white stripes seem so eye-catching at first but in fact they are an excellent disguise. The stocky equines, that always manage to look well fed, blend easily into the environment. When a herd is on the move it is especially difficult to identify individual animals. It is thought that this is also true for predators. Lion and spotted hyena seem to have a hard time trying to single out one animal from a tight, fleeing group of zebras. They hunt only those that lag behind or break ranks. 

The quirks of nature will certainly throw up another zebra with an extraordinary pattern at some stage. A foal with leopard spots on its hindquarters and back, as well as black stripes below and on the neck was seen in the western reaches of the park several years ago. Perhaps there will be another Blacky one day, who is completely black, or maybe even a Whitey! In the absence of conspicuous zebras, scientists meanwhile have to mark animals if they want to study their migratory routes.This was previously done with broad colourful or numbered collars, which was not the prettiest sight for tourists. An Annemarie is definitely preferable. 

Surprisingly, dark animals have only been spotted among Burchell’s zebra, which occur all over Etosha National Park, but not among Hartmann’s zebra which are only found in the western parts of the park. These two species are easy to distinguish from one another. The black stripes connect under the Burchell’s zebra’s belly, there is a shadow stripe between each black and white stripe, and in contrast to Hartmann’s zebra the stripes do not extend down the legs to the hooves.

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