Guided rats controlled through implants in their brains could one day be used to search for landmines or buried victims of earthquakes, scientists say.
An extraordinary experiment has seen researchers steering five rodents - so-called ratbots - through an obstacle course by remote control.
Writing in the journal Nature, the scientists say the ratbots could reach places inaccessible to humans or machines.
The research team is led by Dr Sanjiv Talwar, of the State University of New York, US.
Commands and rewards
Electrodes were implanted into areas of the rats' brains responsible for sensing reward, as well as those that process signals from the whiskers.
The scientists were able to make the rats run, turn, jump and climb where they wanted. The researchers were able to send these commands from distances of up to 500 metres (1640 feet).
The ratbots negotiated an obstacle course which involved climbing a vertical ladder, running along a narrow ledge, hopping down a flight of steps, squeezing through a hoop and descending a steep ramp.
Better than machines
The scientists said: "Our rats were easily guided through pipes and across elevated runways and ledges, and could be instructed to climb or jump from any surface that offered sufficient purchase.
"We were also able to guide rats in systematically exploring large, collapsed piles of concrete rubble and to direct them through environments that they would normally avoid, such as brightly lit, open arenas."
A "turn left" signal was interpreted by the rats' brains as a "touch" on their left whiskers. If the rats correctly followed the cue and turned left, their reward-centres were stimulated, filling the rodents with a feeling of well-being.
Dr Talwar said: "This is an animal with 200 million years of evolution behind it. Rats have native intelligence which is a lot better than artificial intelligence.
Ethical problems
"It is a hard problem simply trying to make a robot move properly over unpredictable terrain. It would be a simple matter to train rescue rats to recognise and home in on the smell of a human trapped under rubble."
Dr Talwar acknowledged there might be ethical objections to such ideas, even if they could save human lives.
"Our animals were completely happy and treated well and in no sense was there any cruelty involved," he said.
"Nonetheless, the idea is sort of creepy. I do not know what the answer is to that."