Though the two may seem entirely unrelated at first, one being a long misunderstood mystery and the other the byproduct of climate change, a new study reveals that a zebra's stripes may too be caused by environmental factors making our sea levels rise.
In a new study published this month in the journal Royal Society Open Science a team of researchers posited that zebra stripes may be an adaptive trait utilized in the process of thermoregulation. And what they found was that while past studies have failed to associate the stripes with social order of a herd or even as camouflaging tactics in the wild, that temperature variations amongst the plains of Africa were a viable way to estimate stripe abundance and density on zebras in the area.
"The adaptive significance of zebra stripes has thus far eluded understanding. Many explanations have been suggested, including social cohesion, thermoregulation, predation evasion and avoidance of biting flies" lead researcher of the study, Brenda Larison says. "Plains zebra striping pattern varies regionally, from heavy black and white striping over the entire body in some areas to reduced stripe coverage with thinner and lighter stripes in others. We examined how well 29 environmental variables predict the variation in stripe characteristics of plains zebra across their range in Africa. In contrast to recent findings, we found that temperature successfully predicts a substantial amount of the stripe pattern variation observed in plains zebra."
Assuming, like many studies before them, that zebra striping is an adaptive trait, the researchers of the study sought out to investigate whether or not the hypothesis could be empirically supported that these stripes act in a way to thermoregulate the species.
"This correlation with temperature may be explained by more than one causal mechanism and will require further investigation" Larison says. "[But] our finding that the two environmental variables most closely associated with variation in striping were both temperature variables lends support to the hypothesis that striping may [in fact] be related to thermoregulation."
"The relationship between temperature and stripe pattern is clear and, along with the lack of genetic structuring among populations, suggests an adaptive explanative for stripe variation."
Though the concept is not necessarily a unique case in all of nature, the thought process and hypothesis that zebra stripes help regulate the individual is novel amongst the many other proposed theories. But it's much less a biological notion, than one we see in nature.
Taking several assumptions and models from environmental studies, this new investigation of zebra stripes bears a striking resemblance to studies in environmental albedo. By studying the contrast in coloration across the globe researchers are able to study how much of the sun's ultraviolet rays are absorbed the by the surface of the Earth and turned into heat versus how much is turned away.
In recent years, with the greenhouse gas effect playing a large factor, the melting of the polar ice caps has decreased albedo making absorption of the rays far greater than in past decades. And with this absorption of heat comes the thermal expansion of water, and thus rising sea levels attributed to climate change. But now too it appears that these changes in the global climate may have something to do with the striations on a zebra-though researchers will continue to investigate other factors that may have a hand in the striping process too.
