Most of us probably picture ants as creatures that march along, single file, a la the song, "The Ants Go Marching One-by-One." We don't typically think of them as falling down out of the sky. But it can, in fact, rain ants.
Cephalotes is a genus of tropical, tree-dwelling ants that can glide through the air. But unlike, say, flying squirrels, they don't glide across distances. When these ants are airborne, it's generally because they're falling. The gliding part comes in because they can steer their falls so they end up back on the tree trunk, where they can quickly race back home. Remaining on their tree home is essential to the ants' survival. The forest floor is often flooded — as much as half of the year — and falling into water equates to near-certain death. Even if the forest floor is dry, once tree-dwelling ants are on the ground it's difficult for them to find a chemical trail back to their tree nests; they'd likely be eaten before arriving safely home [source: Sanders].
How are the ants dislodged from their treehouses in the first place? Cephalotes ants forage for their food at the outer ends of their tree home's branches, where it's not uncommon for a sudden gust of wind to blow them off. Monkeys scampering by can also dislodge them. And if the ants feel threatened — say, by a lizard predator — they sometimes will jump or fall off the tree intentionally, knowing they'll be able to steer their falls so that they will land back on the tree, where claws on their back legs help them hold on [source: Sanders].
While many Cephalotes ants live in South America, three species are found in the U.S., specifically in Arizona, Texas and the Florida Keys [source: Sanders]. Another ant species, Formica aquilonia, found in Europe and Asia, also rains off tree branches in great numbers. One study found 30 percent will intentionally jump out of their tree when birds are foraging nearby [source: New Scientist].