Science of Brow Ridge / Primate Torus CARTA

Morphology of the Brow Ridge

Not to be confused with the backward baseball cap tan

from CARTA /

Considerable variation exists between hominoid species in the morphology of the supraorbital region. Gorillas and chimpanzees (and most fossil hominins) possess a prominent supraorbital torus, or brow ridge, presenting as a continuous projecting ridge above the orbits and nose (although continuous, the torus is anatomically divisible into three regions: laterally positioned supraorbital trigones, medially positioned supercillary arches, and a midline glabellar prominence). In these species with prominent brow ridges, a supratoral sulcus is generally present as a shallow groove just posterior to the torus. (Modern) Humans and orangutans lack prominent brow ridges. Brow ridges may develop as an architectural or biomechanical by-product of hafting a prognathic (projecting) face onto the low frontal bone characteristic of apes and earlier humans, such that the lack of a brow ridge in modern humans is a consequence of their having an orthognathic (vertical) face and vertical frontal (high forehead). Orangutans possess a supraorbital rim (a thin, non-projecting ridge across the orbits) rather than a torus, which may be a function of the airorynchy (backwards rotation of the face towards the neurocranium) that characterizes these apes.
Seemingly thousands of scientific papers, popular musings and other articles focus on TESTOSTERONE / low-high, male-female and the implications in morphology, human variation, attractiveness, social status, etc. So I won’t go into all that here.
But I did notice something about primates, while looking at images under “brow ridge” and related searches.
Nature is “in love with” built-in architectural protection for eyes:
And often combines this feature with other defensive-offensive skull features.
In most primates, male and female skulls have a “torus” that reinforces the eye sockets and provides protection and sun shade – glare reduction for the eyes. 
The vegetarian, mostly docile gorilla, has a significant brow that actually makes it difficult to see its eyes…
which are visible from a certain head position. We might call this the primate dominance gaze. Not overtly aggressive, but perfectly clear as a statement of power.
And, in fact, this “gaze” has been utilized by Hollywood to great effect: it is a standard publicity pose for leading male actors.

Rudolph Valentino

And it is effective in male dominance: Eyes shaded to “hide” information as to one’s mental-emotional state from a possible opponent…
 which increases the visual effectiveness of the true dominance stare. 
which is a lot like the pan-species “predator” stare:

which in modern western cultures is interpreted to be a “sociopath-psychopath” stare.
So be careful…
Military helmets are often designed to amplify the brow ridge effect, especially if it’s missing. And how can we ignore the ultra-male Klingons?
Sunglasses might be considered to be an artificial enhancement or prosthetic “brow ridge”.


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s