Human hands evolved for punching - not just dexterity, according to a new study.
Men whacked punching bags for the study that suggests human hands evolved not only for the manual dexterity needed to use tools, play a violin or paint a work of art, but so men could make fists and fight.
Compared with apes, humans have shorter palms and fingers and longer, stronger, flexible thumbs - features that have been long thought to have evolved so our ancestors had the manual dexterity to make and use tools.
The study's senior author biology Professor David Carrier, of the University of Utah in the United States, said: 'The role aggression has played in our evolution has not been adequately appreciated.
'There are people who do not like this idea, but it is clear that compared with other mammals, great apes are a relatively aggressive group, with lots of fighting and violence, and that includes us.
'We're the poster children for violence.'
He said: 'Humans have debated for centuries about whether we are, by nature, aggressive animals.
'Our anatomy holds clues to that question. If we can understand what our anatomy has evolved to do, we'll have a clearer picture of who we were in the beginning, and whether aggression is part of who we are.'
Prof Carrier agrees that human hands evolved for improved manual dexterity, but added: 'The proportions of our hands also allow us to make a fist, protecting delicate hand bones, muscles and ligaments during hand-to-hand combat.'This relates to an article I read a couple months ago about the role of weapons in human evolution.