Definition:
An “ant mill,” also known as a “death spiral,” or “death circle,” is a phenomenon where a group of army ants (usually from the genus Eciton) become separated from their main foraging trail and begin to follow each other in a continuous, circular motion. This behavior can lead to exhaustion and death as the ants are unable to break free from the cycle.
Etymology:
The term “ant mill” derives from the visual similarity to a milling machine, where materials are processed in a circular motion. The “mill” part of the term reflects the repetitive, circular movement of the ants.
Description:
The phenomenon is a striking example of herd mentality among army ants.
Army ants exhibit herd mentality as they are social insects that operate based on collective behavior. The individual ant‘s actions are heavily influenced by the chemical cues left by other ants. In the death circle, the ants‘ reliance on following each other’s trails overpowers any individualistic navigation effort.
Army ants rely heavily on pheromone trails to navigate. These chemical signals help them maintain coordinated movement as they travel in search of food. Occasionally, the pheromone trail can form a closed loop, leading ants to follow the circle perpetually. Each ant follows the one in front of it, creating a continuous loop. The ants may continue this behavior until they die from exhaustion.
An ant mill can last for several hours or even days, depending on the size of the group and environmental conditions. The diameter of an ant mill can vary but can reach several meters. The phenomenon can involve hundreds or thousands of ants.
Symbolism:
The phenomenon illustrates the dangers of blindly following others without independent thinking.
A circle is an imprisonment symbol. Circling is go symbolism symbolizing madness.