You seem to imagine the state of nature is one of carefree mutualism or somesuch, which is self-evidently not the case. Eusocial animals (which I consider to include humankind) are if anything more competitive than lone or pack animals.
In a governed society, one generally does not face constant attacks against one's territory, and when those attacks do happen (much less often), one has recourse to automatic assistance in defending it, with the threat represented by that automatic assistance acting as an effective deterrent to attacks.
I don't understand this libertarian appeal to nature. Surely we can do better than the drunken walk of evolution that has led to present day "nature".
Territory is very different from property. Territory is something you defend. Property is something society agrees to defend for you.
(I guess I kinda missed the context of the post a bit further up, which suggests there isn't a possessory instinct in nature, which is obviously incorrect.)
As I mentioned elsewhere, I'm increasingly drawn to the conclusion that those who argue most intensely for certain ideological positions are the least comfortable with the idea that our social structures may be biologically determined or could be subject to biological analysis.
Who's talking about "possible"? Any ignorant position is "possible".
Our property laws grew from these exact ways of thinking. Property is natural.