The mystery of why zebras have stripes may have been solved, National Geographic reported. There is solid statistical evidence to conclude that the reason is to keep insects away.
Biologist Tim Caro of the University of California, Davis, who led a team of researchers reported, “We found again and again and again [that] the only factor which is highly associated with striping is to ban biting flies.”
Scientists had been working with five theories to explain the stripes: that they fend off insects, afford camouflage, bewilder predators, decrease body temperature, or have some social value.
Caro and his team used statistical modeling to settle on the insect explanation. They did so by mapping the existence of animals with stripes— including horses, asses, and zebras, along with their subspecies— and found a statistically strong correlation being the habitats of these animals and biting flies.
Neither environment nor predators provided as solid a link as the insect variable.
The full study appears in the April 1 issue of http://www.nature.com/ncomms/index.html Nature Communications.
Not everyone is convinced. Biologist Brenda Larison of the University of California, Los Angeles, agrees that Caro’s hypothesis is the best one supported by modeling data. However, “the story is likely to be much more complex, and this is unlikely to be the last word on the subject,” according to National Geographic.
Scientists say they still need to find out if flies actually avoid stripped animals in the wild. It is hard to get close enough to Zebras to come to definitive conclusions.
“We really need to know what happens with live zebra in the field before we can be sure,” said Larison.
If the team is right, they will have solved a mystery that stumped scientists including Charles Darwin.