These human bones can be tested to determine their age.  Animal bones can be tested, too.  When we can determine when an animal was eaten at a site, then we know when people were there.

It raises other questions, too.  How do we treat the bones of Indians who have died?

Do we have the right to dig up their bones?   What should we do with bones unintentionally exposed?  Whose rights to the bones take precedence, scientists or descendants?  What do you think?