Ants team up to stay dry

From Nature:

Ants A team of engineers has discovered how colonies of ants survive floods by forming themselves into life rafts. The work shows how many simple components can interact to create complex structures and behaviours, a subject that touches on crowd control, urbanization and robotics. An individual ant can float on water for a few minutes, but a clump of the insects is heavy enough to break the surface tension of the water and sink. Yet when a nest of fire ants (Solenopsis invicta) is flooded, the entire thousands-strong colony shapes itself into a raft that can stay afloat for months. “Together they form this really complex material that water should be able to get through, but can't,” says Nathan Mlot, a mechanical engineer at Georgia Institute of Technology in Atlanta.

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