There is a reason behind everything even the black and white stripes of African equids or commonly known as zebras. Before, scientists believed that the purpose of zebras stripes is to keep them cool from the heat of the sun. Based on their theory, it is said that the black stripes get warmer than the white which leads to creating small vortexes that allow the hot and cold air to meet and acts as a fan thus cooling the animal's body. However, a study on July 2018 entitled "Experimental evidence that stripes do not cool zebra's" (published in the Scientific Reports) refuted the said theory. The study might be the answer in the mystery behind zebras' stripes but since there are no zebras involved, a further test should be done for confirmation. The researchers measured the changing temperature of stripped and no-stripped barrels of water left out in the sun.
The mystery unraveled by two scientists, Alison Cobb (amateur naturalist) and her husband Dr. Stephen Cobb (former biology technician) using their field data from Kenya. Their research includes a stallion and a mare zebra as well as a hide draped over a cloth-horse zebra as control. They found out that small-scale convection current created between stripes aids the evaporation of sweat, also their black stripes can erect or rise while the white stripes remain flat.
The researchers were able to find out the zebras' ability to erect their black stripes by comparing the temperature of living zebra to a zebra's hide. The latter one got hotter than the other one by 16°C or 61°F. The authors stated that the raising of black hair transfers heat from the skin to the hair surface. On the other hand, the vortexes (where hot and cold meet) is said to help zebra to avoid blood-sucking parasite.
"Ever since I read 'How the Leopard Got His Spots' in Kipling's Just So Stories, at bedtime when I was about four, I have wondered what zebras' stripes are for," explained Alison Cobb, adding, "In the many years we spent living in Africa we were always struck by how much time zebras spent grazing in the blazing heat of the day and felt the stripes might be helping them to control their temperature in some way."
"The solution to the zebra's heat-balance challenge is cleverer, more complex and beautiful than we'd imagine," she concluded.
