Wars or conflicts can break out between different groups in some ant species for a variety of reasons. These violent confrontations typically involve entire colonies, sometimes allied with each other, and can end in a stalemate, the complete destruction of one of the belligerents, the migration of one of the groups, or, in some cases, the establishment of cordial relations between the different combatants or the adoption of members of the losing group. For some species of ants, this is even a deliberately undertaken strategy, as they require capturing pupae from other species to ensure the continuity of their colony. Thus, there are specific biological evolutions in certain species intended to give them an advantage in such conflicts. In some of these confrontations, ants can adopt ritualized behavior, even governed by certain implicit rules, for example by organizing duels between the most important ants of each colony or choosing a specific location for a battle.
These conflicts are not simply internal to ants, which can fight each other even within the same species, but also involve other animals, particularly other eusocial insects like termites or wasps. In the early 21st century, with the rapid spread of many species into new habitats facilitated by human colonization, significant wars are being waged between different supercolonies.