Fire ants form 'ant rafts' to float on floodwaters

The ants, apart from being waterproof, can link up their limbs to float as one "ant raft" on flooded rivers, evading other objects with fluid group motion.

Ananth Baliga
Fire ants cling together to form an ant raft on water. (Credit: Georgia Tech Ant Lab)
Fire ants cling together to form an "ant raft" on water. (Credit: Georgia Tech Ant Lab)

Nov. 27 (UPI) -- Researchers have found that fire ants can bundle to form solid and fluid bodies, often using this to escape from flooding in forests.

The ants have the ability to link up using their jaws, little claws on the ends of their legs, and a small pad on the end of their foot.


The "ant rafts" are often seen floating down rivers during floods and are able to withstand waves and other forces without breaking apart. But now researchers believe they do constantly break up and relink using their limbs like tiny springs.

"Imagine thousands of people linking their arms together, but everyone has six arms instead of two, and all of their limbs have tiny hooks and adhesive pads on them," said David Hu, professor at Georgia Institute of Technology. "That's why fire ants can do such dynamic restructuring."

These groupings have the ability to flow around obstructions and objects. By breaking up and relinking their limbs gives the ants the flexibility and elasticity to survive the rough flow of flooded rivers.

Aiding the ants in their escape are their waterproof exoskeletons. Fire ants are naturally hydrophobic. But when bunched up a drop of water will bead up without getting them wet. Researchers believe this bunching helps the ants make contact angles of greater than 90 degrees increasing their waterproof nature.


The researchers presented their findings at a meeting of the American Physical Society's Division of Fluid Dynamics in Pittsburgh.

[New Scientist] [Georgia Institute of Technology Ant Lab]

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