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A recent research project reveals that despite popular belief, chimp hands have evolved much more over time than human hands have.
The study was conducted by a team of researchers from Stony Brook University and George Washington University and their findings were recently published in the scientific journal Nature Communications.
They have performed a comparative study of human and chimpanzee hands from both living modern specimens and fossilized ancient species and they have performed elaborate measurements of the hands as a whole and the thumbs and the fingers separately. The human ancestors included in the study were Ardipithecus ramidus and Australopithecus sediba.
The scientists observed that while the human hands have maintained the highly important feature of having elongated thumbs over the course of evolution, that is often considered to have led to the success of the species, the hand in its entirety has evolved little in comparison to chimp hand.
George Washington University spokesperson Kurtis Hiatt pointed out in an interview with Discovery News that the long thumb “facilitates a ‘pad-to-pad precision grip” and that this has basically ensured the success of the human species, due to the precision of their grasp.
This trait is not found in chimps, as they have always had a reduced thumb. Their fingers however have evolved over time, and they have gotten longer and longer, so as to assist them in climbing trees and jumping from branch to branch.
“The findings suggest that the structure of the modern human hand is largely primitive in nature, rather than, as some believe, the result of more recent changes necessary for stone tool-making,” said Hiatt.
Another defining trait of chimp hands is that they are much narrower and longer overall compared to human hands. However, the defining feature between humans and chimps remains the thumb-finger length ratio, that defines the what these two species have used their hands for along the years.
The findings of this study bear particular importance because they bring hard evidence that the hands of the common ancestor of humans and chimpanzees were in fact not chimp-like, as popular theories suggest, but that the chimp hand is in fact a highly evolved version, as opposed to the human hand, that remains rather primitive.
This theory has received mixed feed-back in the scientific world, as some believe that studying the hands of fossilized species and modern chimps and humans is insufficient in order to jump to such an elaborated theory.
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