Why Do Zebras Have Stripes?
Why do zebras have stripes? Biologists have quibbled about it for more than 140 years, but the results of a recent study may have finally yielded a black and white answer to the great stripe debate.
Previous theories as to the purpose of the zebra’s stripes have ranged from camouflage – protecting the zebra with a “motion dazzle confusion effect” against hyenas, lions and other predators in the savannah, to performing a social role – for group identity or perhaps for mating.
Some amusing postulations appeared in the comments section of a National Geographic article announcing the study:
“And I thought they had stripes so that they could use bar code readers to tell each other apart easier!?”
“Cause zebras are sayin’, ‘It don’t matter if you’re black or white!'”
“It’s because in the old days when everything was in black and white they were much harder to spot.”
According to recent scientific evidence, however, the stripes act as a natural insect repellant, deterring tsetse and other blood-sucking flies. The study states, “blood-feeding flies shun stripey surfaces and prefer instead to land on uniform colours.”
The study team found a strong geographical overlap between zebras and the two groups of biting flies, Tabanus and Glossina, that feed on equid species, which explains why zebras would need a shield against this pest. Other equid species, such as wild horses, are far more likely to be plagued by biting insects.
Researchers find comparatively little blood from zebras in tsetse flies, even though the zebra has a thin coat with hair strands that are shorter and finer than those of giraffes and antelopes. At the same time, zebras are far less susceptible to sleeping sickness, a tsetse-borne disease that is widespread among other African equids.
While this theory has not been universally embraced, it does confirm that the correlation between reduced biting-fly nuisance and stripes is “significant”.
Why do you think the zebra has stripes? Should we start dressing in stripes for safari