London: In a first, scientists have found that zebras can manipulate their black stripes to control their body temperatures. The research, published in the Journal of Natural History, shows that it is the special way zebras sweat to cool down and the small-scale convection currents created between the stripes which aid evaporation. They also found that zebras can erect their black stripes — further aiding heat loss.
These three elements are key to understanding how the zebras’ unique patterning helps them manage their temperature in the heat, according to a UK-based biology technician, Alison Cobb and her zoologist husband, Dr Stephen Cobb.
The duo, who have spent many years in sub-Saharan Africa directing environmental research and development projects, assessed zebras in their natural habitat for the first time to investigate the role of stripes in temperature control.
“My early attempts forty years ago at testing this hypothesis involved comparing the temperatures of water in oil drums with differently coloured felt coats, but it seemed to me that this was not a good enough experiment, and I wanted to see how the stripes behaved on live zebras,” said Alison Cobb, lead author of the study.
“The solution to the zebra’s heat-balance challenge is cleverer, more complex and beautiful than we’d imagined. Of course, there is much more work to be done to gather evidence and fully understand how the stripes help zebras control temperature,” Cobb said.
The researchers collected field data from two live zebras, a stallion and a mare, together with a zebra hide draped over a clothes-horse as a control, in Kenya. The data revealed a temperature difference between the black and white stripes that increases as the day heats up.
Whilst this difference stabilises on living zebras during the middle seven hours of the day, with the black stripes 12-15 degrees Celsius hotter than the white, the stripes on a lifeless zebra hide continue to heat up, by as much as another 16 degrees Celsius. This indicates there is an underlying mechanism to suppress heating in living zebras.
