Human Hands Evolved For Fighting, Not Just Dexterity

Summary:
A study run by the university of Utah is now suggesting that hands evolved not only for the dexterity needed to use tools, but for fighting as well. David Carrier, a senior author in the study, says "the role aggression has played in our revolution has not been adequately appreciated." What Carrier means by this is that the aggressive nature of humans has played a role into how we as a species have evolved. Compared to chimpanzee hands, humans have shorter palms and fingers, and a longer, stronger, more flexible thumb. This combination not only allows for humans to use and operate tools, but allows humans to make a clenched fist; something apes cannot do with their long fingers and palms.  When a human makes a fist, it protects fragile hand bones, muscles, and ligaments during hand-to-hand combat. As our ancestors evolved, those that could protect themselves and fend off attackers and hit harder without injuring themselves were more likely to survive, and reproduce with mates. Fights could also be over food, water, shelter, and even "pride" in some cases. The hand "is arguably our most important anatomical weapon," says Carrier once again. The hand not only evolved for the ability to grip things more easily, use tools, but evolved as a weapon to attack enemies and protect themselves.

Relevance:
We have learned about Darwin's idea of Natural Selection, and this is a prime example. Humans that could hit harder to defend themselves to get mates were more likely to reproduce. The humans with the larger hands would not be able to get a mate, and therefore would die, bringing the long, larger hand trait with them. When humans left the trees where they used their long fingers to climb, they no longer needed it on the ground. Selection then favored smaller hands for manipulation because humans did not need to climb the trees anymore, and they could use it for using tools. This also shows how humans evolved and adapted their hands to their new environment.

Author not posted
January 10, 2012
http://www.sciencedaily.com/releases/2012/12/121219223158.htm