Begin by watching how animals relate to each other. There are pecking orders, just like humans in corporations or the military. There are flocks of birds and schools of fish, just like humans at sporting events. There are mothers looking after young, just like humans. There is also a lot of territorial behavior, just like humans with their possessions.
Few behaviors are as widespread as territoriality.
The tiny tropical fish, with a brain the size of a grain of sand, fiercely chases away other tropical fish of the same species. Probably not, which indicates that the dog knows and cares which toy is his. Property isn't just a convention made up by humans, it is one of the most widespread patterns in animal behavior. It is natural to humans just as it is natural to other higher animals. There is another way in which libertarianism is most in tune with nature's way.