A brow bone, in the words of Merriam Webster, is a bony prominence above each eye formed by the part of the suborbital ridge. It can also be said that it is a bony presence on the frontal bone of the skull. It forms segregation between the portion of the forehead and the roof of the eye sockets. In humans or Homo sapiens, these arches over each eye provide mechanical protection. In other animals synonymous with monkeys, these ridges are continuous and straight rather than being arched.
These ridges are more salient in men than in women and vary among different ethnic groups.
Evolution Of The Brow Bone
As humans evolved from Homo Erectus to Homo sapiens, a lot has changed ranging from our eating habits to body structures. Our ancestors, Homo heilderbergenesis, who lived 200,000 to 600,000 years ago had salient brow ridges, therefore, giving them an aggressive facial expression. This helped them establish dominance.
However, as human evolution took place, the foreheads of the forthcoming humans (modern humans) became flatter and more subtle. Prominent brow ridges have been replaced with eyebrows.
In ancient times, brow ridges acted as stabilizers for the skulls to withstand the force of chewing on the vigorous material they ate. However, after the replacement of brow ridges with eyebrows, facial expressions became less aggressive. Something peculiar could be done now: our eyebrows could be raised or creased in subtle and different ways to express different emotions. The facial expression became an important part of communication. Credit could be given to the fact that our foreheads became flatter and vertical.
Brow Ridges Or Brow Bones In Gorillas
Having evolved from species apes to Homo erectus to Homo sapiens, we have come a long way. However, what about other animals of the great ape species?
Gorillas have a significant brow ridge above their eyes, which can be easily spotted. In comparison to humans who have a latent brow bone, the brow ridges of gorillas are straight and protruding above their eyes. A large, prominent ridge helps the gorillas to support the weaker bones in their skull and reduces strain on their head while chewing hard food like nuts.
Loss Of Brow Ridges In Homo Sapiens
Evolution was at its pace when facial reduction and changes in the brain led to a loss of brow ridges in Homo sapiens. This allowed humans to form distinguished facial expressions and friendly gestures. Mobile eyebrows proved to be beneficial in order to establish large social networks and express recognition and sympathy. It paved the way for cooperation and greater understanding among people. These changes took place at a significant point in history and definitely made a drastic impact on the social life of humans. When the interaction between distant groups of humans initiated, making friendly gestures became easier, as brow bones began to fade. Gifts began to be exchanged among our distant friends and thus brought people closer. The ability to make friendly gestures contributed to the healthy social life of humans.