Overpopulation selected possessiveness often defines survivors.

Many animals fight to preserve life-giving territory. Most dog owners understand. Watch a hummingbird protecting a productive bush or feeder.

Overpopulation-selected brains have become so miniaturized that even tiny insects enforce possessiveness. The emerald jewelwing damselfly being is but one sparkling example.

In humans, overpopulation-selected possessiveness is obvious in everything from borders, fences, locks, to criminality, militarism, migration, and empire... Cataloging all consequences of human possessiveness would require great effort.

Until overpopulation's role is appreciated for its impact on human emotional/instinctual drives, our kind likely will not  curb pressures that threaten peace we've enjoyed during underpopulation affluence. Pax Subdentia, the Romans might have called these special moments of underpopulated paradise.