Buzz
Ants are tiny creatures with numerous external dangers: predators, shoes, ant pesticides, and more. Rain might seem like a major threat for these little insects, but surprisingly, you won't see an entire colony washed away by a heavy downpour. These clever insects stay safe and dry in their underground homes.
The ant mounds you spot on your lawn are equipped with multiple protective mechanisms. The first is the mound that sits above the nest. These mounds are typically made from specific types of dirt or sand that soak up water and dry quickly. Water falling on the curved surface tends to bead up and run off the mound's sides.
Certain colonies, such as mangrove ants, will dispatch a soldier ant to seal the entrance with its head. This living plug blocks rain from entering but provides only a temporary solution, as it also impedes gas exchange with the outside environment. [PDF]
When heavy rainfall causes water to seep into the tunnels, it typically doesn't travel far. Ants tend to dig at least a foot underground and have a complex tunnel system that acts like a storm drainage system. Provided the rain isn't too intense, the water will flow through the nest without accumulating.
Through smart tunneling, ants can trap air in various chambers within the nest, with entry points to these chambers coming from below, preventing water from entering.
Even if the small ants are caught in the rain outside, they still have a fighting chance. Ants are too light to break the surface tension of water and can walk on it. Fire ants are famous for forming rafts by clinging together when caught in the rain. This video shows just how buoyant they can be:
