Why do zebras have stripes? Peter Stothard, for The Times:

Black and white stripes? Camouflage to hide from lions? Were Zebra Crossings designed so that the driver couln't see them? I didn't think so ... This week I've been having close natural encounters with zebras - on the ground beneath the bird-filled skies of southern Africa.

In the bush of Madikwe my childhood zebra scepticism is reinforced. The beasts stand out from their surroundings barely less well than the luminous kit of the night cyclist. Further south in the Namibian desert the Attenborough party scores more strongly. The stripes disappear in an early morning swirl of sand and reflection.

The latest zebra lore suggests that scepticism about the camouflage purpose may have been the right course all along. Zoological researchers, it is said, have carefully blacked out the white stripes and whited out the black ones of randomly elected zebra. The result? A hundred times as many nasty biting tsetse flies on the mono-coloured flanks. Those much-debated stripes? Naturally selected insect repellant. Hiding from lions is nothing as to hiding from flies - as any visitor to Africa will attest.

[source: The Times - 'Why the stripes?']

I really like the idea of stripes as nature's fly spray. There are a couple of other theories I can find, though. One is that the stripes help the animals to blur into one when they travel in a herd, causing all kinds of problems for predators, who presumably have to have a good sit down and rub their eyes after ten minutes to get their depth perception back. Equally, the markings might be of more importance to other zebra than other animals, acting as a visual cue for all sorts of courtship purposes, like the plumage of a bird for example.

It's also pointed out in the book Wild Ways, by Peter Apps, that camouflage seems unlikely due to the way zebra move, and the fact that most predators have no trouble at all nailing a few at a time. So if there's any lessons to be learnt, it's that you should wear a Newcastle shirt to protect against insects in Africa, but in such cases, do beware lions.

Finally, to return to Peter's line: "Zoological researchers ... have carefully blacked out the white stripes and whited out the black ones of randomly elected zebra." One hopes, for the validity of their study, that it was not the same zebra.