![]() Note however, that I am not sure whether the skin of zebras are not first white, then turn black and then black fur and then white fur. This an extra reason to claim that zebras are black with white stripes. ![]() This, I suppose, might lead others to rather claim zebras are black with white stripes.įrom answer, it appears that embryos are first black and then white tripes appear. This pattern can also be observed geographically (although there might have other important covariate driving this pattern, such as genetic typically)Īccording to the Brevard Zoo, under their white or black fur, the skin is always black. The most important correlate found so far is temperature, where higher temperature lead to darker and better defined stripes ( Larison et al. All we know is that several environmental variables seem to affect this pattern. The exact developmental pathway for producing these stripes is still very much unknown. Melanocytes either produce black pigments or do not and this cause the alternation of white and black stripes. But it does not mean we can't give some thoughts on the question. We are thankful to him for his continued encouragement.It is not like someone painted a zebra one color (say white) and then painted lines of the other color (say black) on top. We shared a very early draft of our conclusions with him, some months later. Dan Rubenstein, knowing that we believed stripes might have a thermoregulatory effect, was helpful to us in the planning and execution of our fieldwork. In 2003 one of Larison’s co-authors, Prof. We are grateful to two reviewers, who drew our attention to a number of shortcomings in earlier versions of our manuscript. Nick Harberd made extremely helpful comments on the manuscript. Susy Paisley-Day and Judith Harley helped organise and present the data. Josh Ginsberg shared his knowledge of zebras and a belief that stripes are related to thermoregulation Dr. Chris Thouless, for hospitality on Borana Ranch. Nick Georgiadis provided encouragement and facilities and to Dr. In Laikipia District, Kenya, we owe thanks to the owners of Borana, Sweetwaters and Mpala ranches, who allowed us to observe free-ranging zebras on their land to the owners of the two zebras we measured (the late Alec Wildenstein, of Ol Jogi Ranch and Giles and Jasmina Davies, of Mogwooni Ranch) to their employees Christopher Waithaka at Ol Jogi and Stephen Birigen and Mary Nyokabi at Mogwooni, who helped with managing the zebras during data collection to the Mpala Research Centre, whose Director Dr. The ideas that prompted this fieldwork had been intriguing us both since the mid-1970s. The data and observations in this paper suggest that the primary function of the stripes may be thermoregulation and a secondary benefit, fly-deterrence. There is an ongoing debate about the function of zebra stripes, recently focussed on the fact that stripes deter biting flies. We observed that the black stripes can be separately erected, while the white remain flat. ![]() This cooling mechanism explains the lower temperatures of living zebra stripes than those of the inanimate hide. We suggest that the abrupt temperature difference between the stripes causes chaotic air movement above the hair surface, thus enhancing evaporative heat dissipation. Latherin decreases the surface tension of the sweat, facilitating evaporative cooling at the hair tips. ![]() Movement of sweat away from the skin is accelerated by the recently discovered surfactant equid protein latherin, a vital component of cooling in racehorses. Like all equids, zebras sweat to keep cool. The hide temperatures reach 16 oC higher than the living zebras. There is a 12–15 oC difference between living zebras’ stripe temperatures throughout the middle seven daytime hours. The temperatures of black and white stripes on two zebras and a zebra hide were measured, throughout separate sunny days in Kenya. ![]()
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