The primate hands family tree shows how dominant behavior in primates can be linked with hand structure. For example, gorillas & baboons are known to belong to the most dominant/aggressive primate species and both species have a hand structure that is different from other primate species!
It is rather fascinating to see that both species (gorilla + baboon) actually have a hand structure that reminds us of the typical hand differences seen between males and females, incuding: short fingers, broad palms & a low 2D:4D digit ratio.
These biological & evolutionary patterns appear to explain why in nearly all primate species males tend to dominate females. Except for the bonobos of course, females tend to collectively dominate males by forming alliances and use sexuality to control males – interestingly, a few years ago a study reported that bonobos have a rather human-like 2D:4D digit ratio (close to 0.94)… which is illustrative for their rather high emotional intelligence. The Bonobo-society has been described as ‘extraordinarily peacefull’.
This illustrates that Sir Charles Bell was very right about the hand representing capacity, and modern science has still a long way to go in order to understand properly how the structure of the hand corresponds with behavior!
The video ‘Evolution of the human hand’ – presents a detailed picture of how modern science perceives the evolution of the human hand in time. The video is sort of based on Darwin’s evolution theory, but the details were delevered by experts in anthropology who studied how the hand shape, finger length & palmar creases evolved during the past 1.8 million years.
The video demonstrates how the ‘early’ humanoid hands (and primates) are typically featured with 3 or more ‘complete transverse creases’ (multiple simian lines), which are positioned horizontal in the hand + two major vertical lines. While at the end of the video displays a typical human hand featured with only 2 curved, oblique positioned ‘primary palmar creases’ (heart line and head line) + one major vertical line (life line).
And the differences between the human hand and the hands of primates served as a model for the evolution of the human hand in time – see below the hands of a man compared to the hands of a baboon, orangutang & chimpanzee.
Another important figure in the history of medical science was the Scottish surgeon John Hunter, who turned the attention of science from the structure of hands to it’s function:
“Structure is the intimate expression of function”
– John Hunter, Scottish surgeon (1728-1793) –
More details about the evolution of other features of the human hand are presented in the articles: