As a race and as a society we just love our boundaries and our borders; go here, don't go here, this is yours, this is ours. We put up border controls, we tax dependent on what side of the street you live on, you need the right visa stamp in your passport to pass onto this piece of land, which looks identical to the one you're currently standing on but because of a line drawn on a map its ... different.

While lots of the animal kingdom are equally territorial, no one species has managed to invent a whole series of rules and regulations and to employe an entire bureaucracy to ensure the rules and regulations are correctly implemented and patrolled.