Biologists say that as apes evolved into humans, their faces took on fighting features such as thicker jaws and foreheads.
生物学家们认为，当类人猿进化成人类时，为了适应打斗，他们的下颌和额头变得更厚实。
The characteristics were previously thought to be adaptations for a diet of hard-to-chew foods, such as nuts.
之前，这种人脸特征被认为是为了适应那些难以咀嚼的食物，比如坚果。
But researchers at the University of Utah point out that they developed around the same time as humans acquired the ability to curl their hand into a club-like fist.
但犹他大学的研究者们指出，这种现象是和人类能够握拳这一现象同时出现的。
Professor David Carrier said the changes could have been to ‘better protect’ the face when punched.
大卫-卡里尔教授认为，人脸的改变，是为了被拳头击打时对脸部提供更好的保护。
He said: ‘If indeed the evolution of our hand proportions were associated with selection for fighting behaviour you might expect the primary target, the face, to have undergone evolution to better protect it from injury when punched.
他说：“如果我们的手部比例真的是为了打斗才进化成现在的样子，那可想而知拳头的主要目标脸，为了在打斗中更好的保护自己，发生了趋同进化。”
'When modern humans fight hand-to-hand the face is usually the primary target.
“现代人类肉搏的时候，脸通常是主要目标。”
'What we found was that the bones that suffer the highest rates of fracture in fights are the same parts of the skull that exhibited the greatest increase in robusticity.’
“我们发现，在打斗中最容易骨折的骨骼正是头骨中那些最坚固的部分。”
Writing in the journal Biological Reviews, he said that many of these fighting features were softer in the modern human.
他在《生物学评论》发表的论文里写道，现代人类的这种特性已经不太明显了。
However, the modern male face still exhibits some ‘fighting features’ that are less prominent in females. These include thicker, stronger bones in the forehead, cheeks, jaw and neck. And it seems that even over the course of four to five million years, some things have not changed.
尽管如此，这种特性在现代男性的脸上要比女性明显。包括更厚实强壮的额骨、颊骨、颚骨和颈椎骨。这些特性看起来已经延续了四五百万年。
A spokesman for the research team described the early brawls as ‘the prehistoric version of a bar fight, over women, resources and other slug-worthy disagreements’.
研究小组的发言人表示，数百万年前的打斗就像史前版的酒吧斗殴，都是因为女人、资源之类值得一战的争端。