“Stand up straight! And do something about that hair!” Annoying? Sure. But such ___1___ may have made humans what we are today. Because our upright stance, and relative lack of hair, may have enabled our human ancestors to run far and fast enough to capture their prey. So say scientists in the Journal of Human Evolution. [Graeme D. Ruxton and David M Wilkinson, "Thermo regulation and endurance running in extinct hominins: Wheeler’s models revisited"]

The idea that standing on two legs and ___2___ all that body hair might have helped early humans keep cool on the African savanna was first ___3___ in the late 1980s. But those early models had our ancestors standing still in a gentle breeze. Scientists simply didn’t have the computational power to assess what might happen when those early humans had to up and chase down a meal.

The new model ___4___ how hot a human would get running long and hard enough to outlast an animal galloping in the midday sun. And it shows that a hominin would have to have been as energetically efficient, and as hairless and sweaty, as we are today to ___5___. Homo erectus could probably have gone the distance, the scientists say. But Australopithicus probably didn’t have the legs.
【视听版科学小组荣誉出品】
parental advice shedding trotted out takes into account avoid overheating
“站站好！你那头发该修理修理了！”听着反感么？必须的。但也许正是这样的唠叨成就了今天的人类。人类的站立姿态以及长度适宜的头发有利于人类祖先跑得够远够快来猎食。科学家们在《人类进化杂志》上发表了这一观点。 站立姿态以及体毛的去除有助于生活在非洲热带草原的早期人类防暑降温，这一观点早在20世纪80年代末就提出来了。但早期对人类祖先的研究仍很模糊，科学家无法测算出早期人类在追捕猎物的过程中会发生什么。 新模型将正午烈日下，人类在漫长艰辛追捕猎物的过程中会产生多少热量。结果显示，未免过热，祖先们的精力、毛发、汗液都和我们现在一样。科学家说，直立人应该已经走得够远了，但南猿恐怕就没那个福分咯~