It is a societal/legal construct brough up from the historical experience (eg. if a caveman built himself a hammer, they possessed it as long as they took good care of it).

We've redefined what "taking good care of something" means for things you possess, and we made elaborate social/legal constructs to clearly define boundaries of possession.

But this is present even in the animal world, even when it comes to "property" (wolfs mark their territory, so do lions, bees go back to their own hives, etc).