The workers of several ant species have large, flattened, and slightly concave heads that they use as plugs to block entrance to their colonies’ nests.
The so-called ‘door head ants’ are soldier ants with armored heads that match both the size and the shape of the entrance to their colonies’ nests almost to perfection. They function as living doors, using their heads to plug shut the nest and only allow access to other members of the colony while keeping unwanted guests out. Door head ants can be found in several ant genera, including Cephalotes and Carebara. How these species developed the exact size and shape as the entries to their nests is the result of millions of years of evolution.
