According to BBC radio, wood ants hibernate during the winter in insulated ant nests that are built to withstand snow and cold weather. Carpenter ants also lie dormant during the winter but stay active if their nest is located in a warm indoor area.
Ants are often found indoors when a colony is within 100 feet of the structure. Ants frequently colonize in large outdoor wood piles and tree stumps. In certain ant species, the soldier ant's heads are naturally larger than the heads of worker ants. Soldier ants protect their nests from predators by blocking the entrance with their modified heads. When worker ants re-enter the nest, they touch the soldier ant's head with their antennae to gain entrance.