Zebras: Africa’s Horse Tigers
A seemingly endless expanse of tall green grass stretches out before you. As you turn to gather your bearings you see this ocean of grass reaches out to the horizon on all sides with Umbrella Thorn acacias peppering the landscape. You are standing in the African Savanna. But this is not just any part of the African Savana, this is the Serengeti and it’s the middle of The Great Wildebeest Migration. A herd of over 1.5 million wildebeest are making their way across the Serengeti along with over 200,000 zebras and many other antelope species, completing one of the largest land migrations in the world.
Small heard of Plains Zebra (Equus quagga) alongside a large herd of Common Wildebeest (Connochaetes taurinus) and an unidentified Gazelle (Gazella sp.).
There are three species of zebra, all of which are native to Africa. Although they do look very similar, there are a few key differences that can be used to tell them apart - if you can get close enough to spot them. The easiest to pick out is also the most common of the three, the Plains Zebra (Equus quagga). These are the zebras you would see mixed in with The Great Wildebeest Migration and can be easily distinguished from other zebra species due to the vertical black stripes on their body reaching right down to the underside of the belly, as well as the appearance of lighter shadowy stripes that can appear within the white stripes between their darker black stripes. This differs from the Mountain (Equus zebra) and Grévy's (Equus grevyi) Zebras whose stripes don’t quite reach down to their bellies and don’t have shadow stripes. Telling these two apart from one another can be more difficult. Grévy's Zebras generally have thinner and more tightly packed stripes and larger ears than Mountain Zebras. Mountain Zebras have thicker stripes, more akin to Plains Zebras, and also have a fold of loose skin hanging from their neck called a dewlap which is not present in the other species.
Above: Mountain Zebra (Equus zebra) with distinct dewlap.
Above: Grévy's Zebra (Equus grevyi).
Above: Plains Zebra (Equus quagga) with clear shadow stripes on rump and torso.
Africa’s Horse Tigers?
The three species of zebra all belong to the genus Equus which includes zebras, horses, and donkeys. To separate the zebras from horses and donkeys they are placed in the subgenus Hippotigris. Hippo coming from Greek meaning horse or pony and Tigris from Latin meaning tiger. Now this might sound like some scientists tried to make a funny name for the stripy horses as a laugh, which has actually been the reason behind some pretty hilarious scientific names for animals. However, it is believed that zebras were actually given the name in Ancient Rome when they were sometimes used to pull chariots in the Colosseum.
Although zebras may have been given the name Hippotigris based on looks alone, zebras do share another similarity to tigers, their fierce temperament. Zebras or at least their relatives split off from their Equid ancestors over 2 million years ago and have spent that time evolving in Africa where they have been under the constant threat of numerous predator species and are still preyed upon today. This has led to zebras having a very well-developed fight and flight response. This is one of the many hypotheses for why zebras have not been domesticated like their donkey and horse relatives. Zebras live in a world where they cannot let their guard down. With leopards hunting from the trees, lions, hyenas, Painted Dogs and cheetahs hunting in the grass, and crocodiles lining riverbanks just below the surface, it's no wonder zebras have evolved their fearsome attitudes. However, in this land of hungry eyes, zebras are certainly not defenceless. With a kick strong enough to kill a lion you can see why humans decided it might be best to leave them be.
As previously mentioned, these are the most common of the three species of zebra with 6 subspecies spread across Southern and Eastern Africa. With the extinct Quagga, previously believed to be a separate species of zebra, having been reclassified as a subspecies of Plains Zebra based on recent genetic data. Plains Zebras have been assessed by the IUCN as having an estimated total population of 500,000 individuals in 2016 which is a 24% reduction since 2002. This has led them to be listed as Near Threatened and close to classification as Vulnerable. This is also partly due to only 30-50% or 150,000-200,000 individuals being mature.
Mountain Zebras are found in South and Southwestern Africa and include two subspecies. The Hartman’s Mountain Zebra comprises the large majority of the species’ total population with an estimated population just over 33,000 mature individuals. However, due to previous severe reductions of their population in the face of droughts and the increased likelihood of droughts caused by climate change, they have been listed as Vulnerable. The second subspecies is the Cape Mountain Zebra which was left with a total population of just 80 individuals in 1950. But a steady increase in their population has brought them to a total population of at least 1,714 individuals as of 2015 and a listing of Least Concerned.
Grévy's Zebras are the most Northerly situated of the three species, found on The Horn of Africa. Although their current population trend is stable, Grévy's Zebras are listed as Endangered by the IUCN with a population of approximately 1,956 mature individuals as of 2016. This low population is due to massive reductions in their numbers by up to 90% over the last 50 or so years due to numerous causes.
Some of the numerous threats that have and continue to contribute to the current state of zebra populations include livestock farming and ranching, climate change induced droughts, hunting and trapping, residential and commercial development, invasive/non-native species and diseases, war, civil unrest and military exercises.
Despite the overwhelming number of threats that zebras face, I believe where there is love there is hope. These beautiful animals are one of the most well known and easily recognisable animals on the planet and it is this level of connection and love for these animals that gives me hope that we will not stand by and watch these animals go extinct from the great plains, hills and shrublands of Africa.
The current state of Zebra populations is a very real issue. However, it is a sad note to end on and on International Zebra Day, I want you feeling LOVE not loss for these delightful animals. So here are some fun and interesting zebra facts to end on.
After a gestation of 12 to 14 months Zebra foals are born well developed and can stand within 10 to 20 minutes of being born going on to walk and even run within an hour. This is a necessity in an environment teaming with predators.
In 1882 A French naturalist, Émile Oustalet, realised that a Zebra that was gifted to the French president at the time from the government of Abyssinia (now Ethiopia) was not yet a described species of Zebra and named it after the president Jules Grévy.
Let's talk about those stripes
What on earth are they for? Other than looking absolutely amazing of course. Well, there are a number of different hypotheses, however only one seems to have significant scientific evidence backing it. This hypothesis suggests that the stripes help ward off biting insects that can carry harmful diseases. It has been shown that the monochromatic stripes cause confusion in the insects and instead of slowing down to land they just bounce off. One popular hypothesis suggests that due to the difference in heating/cooling created by the alternating stripes help the zebras control their body temperature. Another common hypothesis is that the stripes make it hard for predators to distinguish individuals within a herd when hunting. Despite the lack of evidence due to the difficulties in testing such a hypothesis, I can’t say I haven’t had trouble trying to figure out which head belongs to which body when looking at photos of herds of zebras.
Just one example of how difficult distinguishing individuals from a herd can be.
One crucial role stripes play is recognition between zebras. Although they may all look the same at a glance, each zebra has a completely unique pattern much like that of a human fingerprint. This is especially important for foals (baby zebras) to be able to recognize their mothers. To make sure of this, the mother will often take their foals just outside the herd to allow the foal to imprint on them before heading back to the relative safety of the heard.
Now for the one question to top them all, the question you’ve all been waiting for whether knowingly or not. Are zebras white with black stripes or black with white stripes? The most accepted answer seems to be that they are black with white stripes. This is due to them actually having black skin under their coat with similarly pigmented black hair with the white hair not containing pigments. However, an article by Liz Langley (2017) outlines the many different ways mammal’s hair and fur patterns differ from or match the colours of their skin, including how tigers and snow leopards’ stripes and rosettes actually appear on their skin and the hair/fur growing over it matches the pattern underneath. This is only made more complex when you look as some of the rare colour mutations that have been seen in the wild, from individuals with white and blond stripes to individuals with almost completely brown hair and white spots and stripes. Because of this I’m inclined to simply accept zebras for the striking monochromatic markings that are responsible for their brilliant group name a dazzle of zebras.
What side do you lean to? White with black stripes or black with white stripes? Or do you prefer to sit on the grey fence like me?
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Content warning for the below source as it contains details and descriptions of mass animal abuse relating to the use of wild animals in the colosseum for entertainment:
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