Ant, not aunt, and I’ve come to attack your nes- wait, is that your head?!
In the case of the Cephalotes, yes. These heavily armored ants use their uniquely flat heads to plug gaps in their nests to keep other ants from invading. Living in the tropics where competition among ant species is intense, the Cephalotes reside in tree holes, using their own bodies to close the entrance of the hole, and thereby ensuring that the queen will remain safe. While the ants around the edges eventually die in position, other ants remain alive, and collectively swing open and shut like a large door if fellow ants bring in a large insect or other meal. What remarkable creatures.
(via The Ark in Space)