Hunter-gatherers usually share what with each other whether they want to or not; not sharing, especially with kin, is the kind of anti-social activity that will

Hunter-gatherers usually share what with each other whether they want to or not; not sharing, especially with kin, is the kind of anti-social activity that will get you kicked out of the group and having to fend for yourself on your own in the wild. It is a social fact because ownership is a social fact, not a natural fact.