Army ants don't fight other army ants
When two swarms meet, they either ignore each other or walk away.
Kurzgesagt – In a Nutshell · The World War of the Ants – The Army AntArmy ants don't fight other army ants.
These nomadic ants, which live in groups of millions instead of building nests, hunt in lines that stretch up to 100 metres and can destroy as many as 500,000 creatures in a day. When they find another ant colony, they attack at once and usually win by overwhelming the defenders with sheer numbers, badly damaging or exterminating the colony.
But when two army ant swarms meet in the wild, there is no battle. They either continue onward without engaging the rivals, or both colonies simply withdraw. One explanation is that colonies that fought this way may have wiped themselves out millions of years ago.
Questions people ask
Do other ants fight each other?
Most ant species do. Skirmishes, raids, and full invasions between colonies of the same species happen every day and cause millions of casualties. Army ants are the strange exception, and only with each other.
Why would an army ant battle be so bad for both sides?
Because both sides use the same weapon: overwhelming numbers. A fight between two swarms of millions would be long, costly, and leave the winner too weakened to hunt or survive. Avoiding the fight preserves both colonies.
What do other ants do when army ants attack?
They are in trouble. Army ants are not especially strong individually, but they attack as a social unit and overwhelm victims before a defense can form. Many species flee with their larvae, and some block their nest entrances with specialized workers that have big, square heads.