Bio-inspired robots can mimic live fish

Scientists have developed bio-inspired robots that "see" and mimic the behaviour of live fish in real time and may help improve our understanding of marine animals. Biomimetic robots have been deployed alongside live animals to better understand the drivers of animal behaviour, including social cues, fear, leadership, and even courtship.

However, the encounters have always been unidirectional — the animals observe and respond to the robots. Scientists at the New York University in the US have now developed robots that can watch back. Researchers tapped advances in real-time tracking software and robotics to design and test the first closed-loop control system featuring a bioinspired robotic replica interacting in three dimensions with live zebrafish.

The team tested the interaction of the robotic replica and live zebrafish under several different experimental conditions, but in all cases, the replica and the live fish were separated by a transparent panel. In preference tests, zebrafish showed greater affinity and, importantly, no signs of anxiety or fear — toward a
robotic replica that mirrored its own behaviour rather than a robot that followed a pre-set pattern of swimming. While mirroring is a basic, limited form of social interaction, these experiments are a powerful first step toward enriching the exchange between robots and live animals.

"This form of mirroring is a very simple social behaviour, in which the replica seeks only to stay as close as possible to the live animal," said Maurizio Porfiri, a professor at NYU. "But this is the baseline for the types of interactions we're hoping to build between animals and robots," said Porfiri, who led the study published in the journal Scientific Reports.

"We now have the ability to measure the response of zebrafish to the robot in real time, and to allow the robot to watch and manoeuvre in real time, which is significant," he said. Scientists are now investigating social interactions among live zebrafish to better understand the animals' natural cues and responses.

"We are learning what really matters in zebrafish social interactions, and we can use this information to help the robot interpret and respond appropriately, rather than just copying what it sees," he said.