Biologists say that as apes evolved into humans, their faces took on fighting features such as thicker jaws and foreheads.

生物學家們認為，當類人猿進化成人類時，為了適應打斗，他們的下頜和額頭變得更厚實。

The characteristics were previously thought to be adaptations for a diet of hard-to-chew foods, such as nuts.

之前，這種人臉特征被認為是為了適應那些難以咀嚼的食物，比如堅果。

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.

但猶他大學的研究者們指出，這種現象是和人類能夠握拳這一現象同時出現的。

Professor David Carrier said the changes could have been to 'better protect' the face when punched.

大衛-卡里爾教授認為，人臉的改變，是為了被拳頭擊打時對臉部提供更好的保護。

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.

他說：“如果我們的手部比例真的是為了打斗才進化成現在的樣子，那可想而知拳頭的主要目標臉，為了在打斗中更好的保護自己，發生了趨同進化。”

'When modern humans fight hand-to-hand the face is usually the primary target.

“現代人類肉搏的時候，臉通常是主要目標。”

'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.'

“我們發現，在打斗中最容易骨折的骨骼正是頭骨中那些最堅固的部分。”

Writing in the journal Biological Reviews, he said that many of these fighting features were softer in the modern human.

他在《生物學評論》發表的論文里寫道，現代人類的這種特性已經不太明顯了。

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.

盡管如此，這種特性在現代男性的臉上要比女性明顯。包括更厚實強壯的額骨、頰骨、顎骨和頸椎骨。這些特性看起來已經延續了四五百萬年。

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‘。

研究小組的發言人表示，數百萬年前的打斗就像史前版的酒吧斗毆，都是因為女人、資源之類值得一戰的爭端。