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The legendary army ants are confined mainly to the tropical regions of India, Africa and South America. In some cases they are found as far north as the Mississippi Valley and south to Patagonia. These ants are often more than one inch long, with such a distinct difference in the male, female and worker, that scientist have sometimes classified them as separate species. The queens are wingless, while the males are winged and more wasp like in appearance. The workers vary in appearance with some being very large with powerful jaws while others smaller. Unlike the more settled existence of other species of ants, the army ant lives a nomadic existence. They are constantly moving about in the forest and have no permanent nest.
One of the great wonders to see is a colony of army ants on the march. The resemblance of the march to columns of humans is striking. There will be a main body of small workers and large jawed workers flanking the main columns. These serve as scouts as the continually move ahead laying scent trails to mark the way for the main body. In many cases the press of the main body is so great that branches of columns split off. This appears to serve when any slow moving prey is approached since the ants can surround and engulf the victim. As they move the activities alter between foraging and resting. In some cases the main body will move under ground building tunnels so rapidly that the secrecy of the advance is maintained. Although the army ant feeds mainly on insects, little or nothing that is too slow escapes their attack. Once these insects are on the march even slow moving snakes or man, if he is foolish enough to allow his curiosity to mislead him, can escape unscathed. Although many of the stories about the attacks of army ants have been exaggerated, there are records of such animals as tethered horses being found with nothing but a skeleton to show. In spite of their reputation the army ant is often known to perform a service to man by ridding the area of vermin, rats, mice, spiders, cockroaches, bugs, beetles and more.
The pattern of the movement of army ants seems to depend largely on their breeding cycles. Each 30 to 40 days the huge queen produces between 25 to 35 thousand eggs. This is done in a two day period. A few days before this occurrence the entire colony will stop and gather in a vast swarm with individual ants hooking themselves together with their legs. This forms a chamber for the queen to lay her eggs. When the eggs hatch the ants remain static while the workers provide food for the larvae. After about a week the larvae hatch producing workers and males. The movement of the young excites the older ants into a cycle of nomadism and the colony again is on the move. The winged males are constantly leaving the colony to seek out new queens and start other colonies. How they discover their new queen is still unknown even though it is believed that they follow the trails of other colonies. The male army ants are enormous insects with wings, big compound eyes and huge sickle shaped jaws. In West Africa they are often found flying around lights and have been dubbed the sausage fly. In cases where a daughter queen emerges in a colony each female will gather around her portions of the population and the new colonies will go their separate ways. In some species the new queen is killed and the colony remains together.