wider and more open than a male pelvis. Another key difference can be seen in the sciatic notch. The sciatic notch in females tend to be wider than the sciatic notches of males. The pelvic inlet is also a key difference. The pelvic inlet can be observed as oval-shaped in females and more of a heart-shape in males. The difference in inlet shape is related to the distance between the ischium bones of the pelvis. To allow for a wider and more oval-shaped inlet, female ischium bones are further apart from one another than the ischium bones of a male. Differences in the sacrum between males and females can also be attributed to the needs of child birth. The female sacrum is wider than the male sacrum. The female sacrum can also be observed as being shorter than the sacrum of a male. The difference in width can be explained by the overall wider shape of the female pelvis. The female sacrum is also more curved posteriorly. This could be explained by the need for as much space as possible for a birthing canal. The articulating coccyx in females is also generally observed as being straighter and more flexible than the coccyx of a male for the same reason. Because of the female pelvic bones in general being further apart from one another than those of the male pelvis, the acetabula in a female are positioned more medially and further apart from one another. It is this orientation that allows for the stereotypical swinging motion of a female's hips while walking. The acetabula not only differ in distance, but depth as well. It has been found that female acetabula have a greater depth than those in males, but also paired with a smaller femoral head. This in turn creates a more stable hip joint(insert). One of the last key differences can be seen in the auricular surface of the pelvic bones. The auricular surface where the sacroiliac joint articulates seen in females generally has a rougher texture compared to the surfaces seen in males. This difference in the texture of the articulating surface may be due to the differences in shape of the sacrum between males and females. These key differences can be examined and used to determine biological sex between two different sets of pelvic bones; all due to the need for bipedal locomotion while having the need for