Like something out of a Victorian jungle story, big rafts of teeming fire ants have been seen this week floating in South Carolina on high water that has also ruined homes and businesses and killed nearly a dozen people.
When waters start to flood a fire ant colony, they take evasive action. Worker ants link legs and mouths together, weaving a raft in a process that can take less than two minutes (see pictures).
The ants move their queen and larvae to the center of the raft, where they stay high and dry on top of the mass of bodies. The fine coat of hairs on the ants traps enough air that those on the bottom layer of the raft avoid being completely submerged.
Fire ants can survive in a raft up to several weeks, though they must eventually reach dry land if they are to restart their colony. In the water, they face constant danger from predators, particularly fish, who pick them off one by one. If enough ants are removed, the whole colony can collapse.
A single queen can lay three million eggs in her lifetime, so many of the workers lost in the struggle can be replaced.