Green guardsmen guard white walls and white guardsmen guard green trees.
Within walls live men, women, children and grandparents. In trees live squirrels, birds, apes and bees.
Birds eat nuts, squirrels hide them, apes find them, children play with them and bees just make honey. Men and women sometimes climb up trees to eat the honey, but bees sting.
This is how they live.
One day the children grow up and decide to build more walls. They cut down the trees and burn them to the ground. The green guards then fight with the white guards, but the grandparents tell them to stop.
The roots of trees can cause walls to crack and fall down, so the white and green guards find themselves fighting again. Again the grandparents tell them to stop because within the white walls live all the guardsmen, along with their wives and children.
Over time there are more and more walls and fewer trees. Guardsmen now build walls, some for bees to live in and safely make honey, and some for the rest of the animals to live in - walls we call zoos.
This is how we live.