Red imported fire ants are extremely resilient and have adapted to contend with both flooding and drought conditions. If the ants sense increased water levels in their nests, they will come together and form a huge ball or raft that is able to float on the water, with the workers on the outside and the queen inside. Once the ball hits a tree or other stationary object, the ants swarm onto it and wait for the water levels to recede. To contend with drought conditions, their nest structure includes a network of underground foraging tunnels that extends down to the water table. Also, despite the fact that they do not hibernate during the winter, colonies can survive cold conditions as low as 16 °F (−9 °C).