Archaeologists find the pelvis of a primitive human and are able to identify the sex, the relative age, and some physical characteristics of the individual. How is this possible from only the pelvis?
People tend to forget that bone is a living, dynamic tissue, and that it changes throughout your lifespan. Any bone in your body can provide clues to who you were and how you lived; the pelvis can tell more than some bones because it has a slightly different shape in males and females, and also because it sustains some permanent changes during pregnancy.
Every skeletal muscle is attached to bones at areas called insertions. The sizes of the insertions on a bone can indicate how well developed the muscles were, which can give some indication of the person's lifestyle.
Bones age along with the rest of you, so osteoporosis, arthritis, and general wear and tear can be indicators of age. There are also some diseases which can leave distinctive marks on bones; examples are syphilis, Paget's disease, and osteomalacia.
Here are some additional sources that may be of interest to you:
Of these, the one that looks especially fascinating is this one:
It's pretty fascinating, isn't it? Here's a link that explains how it works.
Basically, they measure the pelvis and they know the average pelvis size at different ages. Male pelvises look different than female, so they can tell if it is male or female and approximately how old.
it is like biology