![]() ![]() Additionally, this theory applies only to flat, horizontal surfaces parallel to the ground. What’s more, even if these the swirls of cooling air were to form, they would be easily disrupted by any passing breeze or even the slightest twitch of a zebra flank, according to Timothy Caro, an evolutionary ecologist at the University of California at Davis. For one, the theory makes sense only in direct sunlight: in the shade, the lack of juxtaposition between hot black air and cool white air would preclude the formation of icy vortexes. This is not the first time that scientists have poked holes in the “cool stripes” theory. The experiment determined that when it comes to temperature regulation, stripes, it turns out, have the flash, but not the substance. The amount of whiteness in the coat seemed to be the biggest predictor of cooler internal temperatures. ![]() But while the black stripes were consistently hotter than the white stripes on both the real and artificial zebra hides, reliably mimicking the contrast observed on the hides of living zebras, the core temperatures in both zebra barrels were about the same as those in the brown- and gray-coated containers. On the other end of the spectrum, the black cattle hide kept its canister cooking at a temperature hotter by 6 to 7 degrees Celsius. Unsurprisingly, they found that the white cattle hide kept its barrel coolest in the afternoon sun. They then placed thermometers inside the canisters to measure the internal temperature of the water within. In their study, published last week in the journal Scientific Reports, the researchers covered metal barrels with white cattle hide, black cattle hide, brown horse hide, light gray cattle hide, real zebra hide or an artificial coat composed of stripes of black and white cattle hide as a zebra imitation. In keeping with this idea, one team of researchers published findings in 2015 that demonstrated the warmer the climate, the stripier the zebras.īut Horváth and colleagues from Hungary and Sweden have shown that black and white stripes are no better than uniform brown or gray at keeping the heat at bay-at least, if you’re a barrel full of water. When these hot pockets meet the comparatively sluggish air moseying over the white stripes, the clash could create little vortexes of chilled air. Because black hair absorbs more heat than white hair, the air above black stripes may be prone to forming strong, fast microcurrents. One longstanding theory posits that the stripes are actually conducive to keeping zebras cool. The experimental barrels, coated in hides of black, gray, brown, white, or black-and-white stripes, basking in the afternoon sun. Strange as it may seem, biophysicist Gábor Horváth and his colleagues had placed the barrels not for the sake of eccentric art, but to settle an age-old evolutionary debate: why do zebras have stripes? From far away, they almost resembled the torsos of lazily grazing animals-only, when flies flicked thirstily onto their sides, no tail swatted them away. Each barrel was outfitted with a different skin: white, black, brown, gray or black-and-white stripes. Two main theories still remain that the contrasting colours help create an optical illusion which confuses predators or that the pattern discourages flies from landing on the zebra.Last summer, a series of rather unusual water-filled canisters were left to bake in the northern Hungarian sun. To their astonishment, the zebra-print material had an extremely similar temperature to the grey one – proving that the zebra print did not help to lower the temperature. To test the theory, the researchers placed barrels of water covered in different colour materials – black, white, grey and zebra-print – in the hot sun, and monitored the temperatures. This was thought to create air currents around the zebra that would keep it cool – a useful trick in the hot, African savannah! However, this theory has now been disproven by researchers in Hungary. The white stripes were thought to absorb less light and therefore be cooler, while the black stripes would absorb more light and heat up. Until recently, it was widely believed that zebras’ black and white stripes kept them cool. It’s a question that has baffled science for donkey’s years… Why do zebras have stripes? Scientists have debunked a popular theory as to why zebras have stripes! ![]()
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