Male or Female?

      Have ever wondered how those scientists on shows, like on Bones, identify a skeleton as male or female? Read on and I will tell you just how they do it. This process is called “sexing.” Now, “sexing” can never be called “gendering” or of the sort because they are two totally different things. Gender is how an individual sees themselves, whether or not they get operations to change their physical appearance. But sexing is more than skin deep. No matter how many surgical procedures an individual undergoes, no amount of surgery could change their skeletal make up by which they are sexed as. Let me start with the male skull.
       The reason I am starting with the male is because it has formations the female skull does not. If you would look at the picture below, you can see the ridges on top of the orbits (eye sockets). This ridge is exclusively for the male skull. The mandible (lower jaw) is also a more square shape towards the chin. There is also another formation. When looking at the male skull from the side there is a notch towards the bottom of the skull, but not all the way towards the bottom. On the bottom of the skull that is more evidence that the skull is male. On the bottom there is something physical anthropologists call the Mastoid process. This part of the male skull is much larger than the female, which I will speak of soon.

       Next up how to tell if the skeleton is male is the pelvis. I must say, it is good that the male and female skeletons can be told apart by more than just the skull; because sometimes the skull is not accessible. This looks like a normal, pelvis, right? Nothing weird...for a male that is. After these pictures concerning the male I will get to the female, but before I do, pay attention to how the male pelvis is closed. The sacrum and coccyx (the tail bone) is bent far ahead, and the ilium (the wings of the pelvis), are mostly closed in. The male hip usual lines up straight with the femur (upper leg bone), but the with the female it is completely different.

       The female femur lines up more beneath the hips than for the male. Reason being is the female pelvis is much wider than the male because the gap between the ilium is open to make childbirth easier. Also, you may notice in the picture below, the sacrum and coccyx are both much further back; again this is for the reason of childbirth. No matter if the woman had given birth in her life or not, these bones are predisposed in this way because early on in our evolution new children were vital for our survival. Albeit the mother would most likely die giving birth. Side note: when we were still quadrupedal (walking on all fours), the birthing was much easier because of that walking position. It is because we are now bipedal that birthing is much harder for human females. I have included a picture of a human female pelvis and a female chimpanzee pelvis at the end of this blog to illustrate my point.

       We now end where we began, the skull, but this time the female skull. If you remember the reason I started off with the male skull is because it has formations the female skull does not. Look at the picture below. The human female skull is without the brow ridges, the mandible is more pointy and rounded towards the chin, no notch towards the back, and the Mastoid process is small compared to the male. Usually when a human skull is found in a crime scene, or just by physical anthropologists , the first thing they look for to sex the body if the skull is available are the brow ridges. This one formation or lack of, can sex the skeleton. Although, with that said, if the skeleton is that of a small child who has not gone through puberty sexing that is much harder because their skeletons are not distinguishable to confirm male or female.  

       I hope that I have satisfied your curiosity on how these super-sleuths, otherwise known as physical anthropologists, can deduce the sex of a skeleton they are presented with. As a matter of fact you can feel these differences while humans are still alive. If you are a female, press down on your forehead above your eyebrow then move your hand til your reach the outline of your supraorbital margin (top of your eye socket). You may not notice any difference, but if you go to a male friend and, with his permission, feel his forehead you will be able to feel the difference in your bones. And if you are male do the same, but you will be able to feel a slight ridge before reaching your supraorbital margin. This time go to a female friend and feel her forehead, again with her permission. The only sexing bone you will not able to feel are the difference between the pelvis. 
Now there is another method to sex a skeleton, but this one requires much exposure to different skeletons to be able to sex them using this method. Reason being is that a lot of long bones (humerus, femur, tibia), look the same to the untrained eye. Those who have been exposed to bones can tell the sex just by the size of the long bones.
       As promised, below on the left is a human female pelvis, and on the right the pelvis of a female chimpanzee (as we began bipedal our skulls grew, but we were once as small as permitted by the pelvis to slip through without any trouble).
       Please feel free to leave me a comment either about this blog or on an anthropological subject you would like me to cover.