This is pretty old but I thought I’d put it out there in light of recent movements by our future robotic overlords to become autonomous. The Energetically Autonomous Tactical Robot (EATR) by RTI has a built-in foraging system that can harvest biomass as well as fuel like gasoline, propane, coal, and solar energy on the go. It powers itself with a combustion engine and can hunt out and ingest these foodstuffs automatically.
The fact that these things will get buzzsaw arms is slightly disconcerting but expected. While most of the human quarry will already be caged by the time EATR comes to power, there may be some folks who have run off the reservation and need to be brought back, honeybee-style, on the rear legs of an EATR STRIDR. Damn, 2012 is going to suck.