It’s not all black and white

hr-shutterstock_127616915The zebra is the quintessential African animal ― the fat horse in stripy pyjamas at the end of every child’s alphabet ― but there’s more to them than meets the eye, says Mike Unwin

There are three different species of zebra, all of which inhabit woodland, savannah and arid terrain across southern and East Africa. They are highly sociable grazing animals that live in family groups, and in some areas ― famously the Serengeti ― gather in mass migrations. Their principal predators are lions and spotted hyenas. The plains zebra, the most common species, stands up to 1.3m at the shoulder and weighs up to 350kg. It lives around 25 years in the wild. A female gives birth in summer after a 360-day gestation period. Her single foal stays close and can move with the herd within half an hour of birth.

The stripes on a zebra’s neck continue onto its mane, which is composed of stiff, erect hairs. They nibble each other’s mane and neck to reinforce social bonds during mutual grooming.

A zebra has keen hearing. Its ears are highly mobile and also play an important part in communication ― laid flat, for example, they can either signal fear or aggression.

Zebra use sharp incisors to nibble off tough grasses before grinding them down with broad cheek molars. They bite aggressively in self-defence or during territorial skirmishes, and bare their incisors as a threat display.

Powerful legs allow zebras to reach speeds of 25mph and provide enough stamina to outrun most predators. Similar to horses, they have four gaits: walk, trot, canter and gallop. Their powerful backwards kick, given in self-defence, can break a lion’s jaw.

Like all members of the horse family, zebras are odd-toed ungulates. They walk on tiptoe on a single central toe, which is protected by an enlarged toenail: the hoof.

The efficient digestive system allows a zebra to process coarse grasses unpalatable to many other herbivores, and it may feed for 22 hours out of 24. Its plump, healthy appearance may partly be explained by the fermenting action of bacteria in the gut.

A zebra’s tail ends in a tassel, and is used as a fly-whisk in order to repel biting insects. Those with missing tails may have escaped attacks by crocodiles or other predators, or may have lost their tail in a fight with a rival.

Which zebra?

Today there are three species of zebra. All are confined to Africa and belong to the genus Equus, along with all other living horses. These are:

Plains zebra (Equus quagga)
Much the most common zebra and the one seen by most safari-goers, often alongside other grazers such as blue wildebeest. Ranges from Kenya to South Africa and occurs in six subspecies, all of which have stripes that wrap around the belly and become broader towards the rump. Of these subspecies, the Grant’s zebra is found in the Serengeti-Mara Ecosystem; Burchell’s and Chapman’s inhabit southern Africa; and Crawshay’s occur in Malawi and Zambia.

Mountain zebra (Equus zebra)
Confined to southwest Africa and distinguished from plains zebra by narrower striping on the flanks, a white belly and prominent dewlap. There are two races, both very localised: Hartmann’s mountain zebra, the larger, occurs in central and southern Namibia; Cape mountain zebra ― once close to extinction ― in South Africa’s Cape. Hardy animals of rugged terrain, they supplement poor grazing with browsing.

Grevy’s zebra (Equus grevyi)
The largest zebra, weighing up to 450kg, and the rarest ― its remaining population of no more than 3000 is largely confined to arid northern and central Kenya. Distinguished from the plains zebra by its round ‘Mickey Mouse’ ears and narrow pinstriped pattern, the stripes become finer towards the rump.

Why the stripes?
The scientific jury is still out. The traditional explanation was that stripes provided camouflage in the long grass, but other animals that use them for this reason are generally more solitary. Besides, zebra can look very conspicuous against a lush, green meadow. More intriguing is the ‘motion dazzle’ theory, which holds that the confusion of black and white baffles a predator trying to select a target from the herd. Other theories suggest that the differing of patterns between individuals is an aid to recognition, and even that the stripes act as a deterrent to flies. Most recently, scientists have explored the idea that they help in thermoregulation, allowing the animals to withstand intense solar radiation. Whatever the truth, this animal certainly gets 10 out of 10 for style.

Social life
Zebras live in small family groups comprising a stallion with a harem of mares and their foals. Young males also form bachelor herds. The females in a group observe a strict hierarchy: they are led by the dominant mare, with others following in single file, according to rank, each with her foal behind her. The stallion usually brings up the rear but may take the lead in risky situations. Group members maintain strong bonds, reinforced by mutual grooming. They communicate constantly, deploying a subtle body language of head, ears and tail, and making a variety of calls, including a far-carrying, hiccuping kwa-ha-ha. Group members look out for one another: if one becomes separated from the others, they will search for it.