Living Ant Bridges Have Implications for Robotics

Imagine this scenario: An earthquake strikes, collapsing the ends of a crowded bridge. People are stranded on the bridge’s interior, the gap to land being too big to jump. Emergency crews dispatch, but discover upon arrival that any sort of human intervention borders on fatal. Instead, the crews send out an array of insect-like robots. The robots coalesce, forming a platform where the gap once was. The trapped people cross safely to land.

While the above scenario is hypothetical, researchers have discovered army ants, known for building living bridges by linking their bodies, are capable of moving their bridges from the original building points to cover larger swaths.



Army ants, which populate areas of Africa and South and Central America, live a nomadic lifestyle, only inhabiting temporary nests. On their traverses through the jungle, they encounter a number of obstacles. But their ability to build living bridges facilitates travel in a quick and efficient manner. It only takes seconds to assemble and disassemble a bridge.

“These bridges change dynamically with the traffic pattern on the trail,” said Christophe Reid, co-author of the study and a postdoctoral researcher at the Univ. of Sydney. “Imagine if the George Washington Bridge between New York City and New Jersey would reposition itself across the river depending on the direction of rush-hour traffic.”

The study was published in the Proceedings of the National Academy of Sciences. Prior to it, researchers believed the living bridges were static.

According to Reid, the bridges start at intersections between twigs and lianas. Eventually, they move slowly away from their starting point to create shortcuts and lengthen as needed.

“The final position of the structure depended on the intensity of the traffic and the extent of path deviation and was influenced by the cost-benefit trade-off at the colony level, where the benefit of increased foraging trail efficiency was balanced by the cost of removing workers from the foraging pool to form the structure,” the researchers write.

Reid said the research may be helpful for self-assembling systems, such as reconfigurable materials and autonomous robotic swarms. “These systems could…enable robots to operate in complex unpredictable settings, such as in natural disaster areas, where human presence is dangerous or problematic,” Reid said.

Already, other researchers are working on creating self-organizing robotic systems. Last year, Harvard Univ. released a video showing their robots assembling into various shapes. It’s only a matter of time until the technology advances enough to have life-saving implications.