Two key aspects of most living organisms is their ability to detect and exploit natural sources of energy within their environment. We are currently developing a robotic system that will attempt to sustain itself by hunting and catching slugs on agricultural land. A microbial fuel cell will be used to convert the slug bio-mass to electricity thus providing the robot's energy supply. This paper outlines the requirements for such a predator and describes the entire robot. Data is also presented from trials of the robot hunting and catching slugs in a situation similar to that found in agricultural fields.