Distinguishing between male and female human remains can be tricky, especially in cases where only partial skeletons are found. Ann Ross, a forensic anthropologist at North Carolina State University in Raleigh, and her colleagues have developed a new computer program called 3D ID that helps researchers make such distinctions based on skulls. Check out the video below, and as you watch the female and male skulls rotate, look for these features:

Nuchal crest: This area, where the muscles from the back of the neck attach to the base of the skull, is smooth and rounded in females but hooked and protruding in males.

Jaw: A female jaw is often smaller than a male's and either pointed or rounded, whereas a male's is broader and squarer.

Forehead: Female foreheads are more vertical than male foreheads, which gives the former a childlike appearance, Ross says.

Brow: An area called the supraorbital margin, which is just above the eye and roughly follows the brow line, is thin and pointy in females but more rounded in males. Male browridges are also more pronounced.

Even before a gender determination is made, researchers must figure out if remains belong to a human or a nonhuman animal. In fact, Ross keeps various partial animal skeletons and skulls on hand in her lab for reference and to help her train students to learn how to recognize differences among them.

» View a slide show and learn the identity of a few animal skulls

4 Comments

1. 1. Marc Levesque 06:14 PM 10/16/11

   What is the error margin of the software when it is identifying male and female skulls today?

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2. 2. Archimedes 06:20 PM 10/16/11

   Not mentioned in the original article is the fact that the size of the brain in males is significantly larger, on average, in men than in women. The same results in a skull that is larger, on average, in men than in women.Just by looking at the skulls presented in this article, it is relatively easy to discern that the male skull is significantly larger in the male. This difference in average skull sizes between men in women has been known for thousands of years. Of course, this is an AVERAGE difference. Some women have skulls and brain sizes significantly larger than the average male and some males have skulls and brain sizes significantly smaller than the average female.

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3. 3. NatWu 09:16 AM 10/17/11

   Nagnostic, your comment is inappropriate and incorrect. Archimedes correctly pointed out that on AVERAGE male skull sizes are larger than female, but this is about the least useful metric when sexing human skulls. There is too much overlap in modern humans for this to even be a metric, which is why this article correctly doesn't bother mentioning it. You could never look at a human skeleton and say, "It falls within average male size therefore it is male". If you've happened to be in a large crowd of people you would have noticed there are plenty of women bigger than the average man, and vice versa. That's why they are pointing out all the actual differences between male and female that you use to sex a skull!
   
   You're the one with an ax to grind; if you'd been in a human evolution or human anatomy class recently you certainly would have heard about these sexual differences, including the fact that male skulls (and brains) are, on average, larger than female skulls. There's a good reason to discuss it since it illustrates the point that larger brains are needed for larger bodies, not that it makes men smarter!
   
   Comments like yours are unconstructive, and more importantly, unscientific. Please keep your flagrantly biased opinions to yourself.

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4. 4. rainyforest273 10:06 AM 10/17/11

   If I'm not wrong, there is a procedure for the remodelling of face over a skull? Doesn't this help in determining the gender from a skull via facial features as well?

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