Animals are enough intelligent and if we put them into circular loop then they are not going to follow loop till death. But this is not true in the case of army ants which have the strangest behavior where they make a circle and follow each other until they are not dead. The strangest behavior of army ants committing suicide by making spiral is one of the weirdest sights in nature.
Army ants are the one of the most brutal killing machine on the earth. They can hunt and eat 500,000 prey animals each day. They march in trail which is 20m wide and over 100m long. Army ants not live in nest but make a nest with their bodies by holding each other with different layers in a well-organized structure. Where inner ants are younger female worker and outer layer has older female worker and top most layer is guarded by army ants layer.
Researcher says when army ants marching then one can know this by the reaction of other animal of the forest. The insect make noises and flee from army ants and bird chases ants from the sky and eat left overs that left by the army ants after hunting.
But army ants have serious issue they are completely blind and can easily disorient and can be stuck in a circle where they can walk behind each other until they die of starvation and tiredness. Army ants are then unable to break loop because of lack of sights.
One can create death of circle for army ants by putting them into plant pot or enclosed space. Army ant follow the trail of pheromone that other ant leaves. This system work well always until ant not stuck in circle or condition where they start following each other in unbreakable loop.
The largest death of circle observed for army ants are 1,200 feet in diameter and ant completing this circle in two and half hour for making one round. The mysterious cause which compel whole colony to do mass suicide by making the ant mill create many question then answers?