Loneliness of long-distance robot
24 February 2011 Last updated at 16:46 GMT
Five knee-high mini-robots have set off on the world's first robot marathon, the Robo Mara Full race in Osaka, Japan.
The battery-charged machines will race 423 laps around an indoor 100-metre track in Osaka's Asia Pacific Trade Centre.
The marathon is expected to continue until Sunday.
Roland Buerk reports.