Two years ago we showed you Boston Dynamics' incredible BigDog—one of the world's most ambitious legged robots—being developed for DARPA and the U.S. Army. With its advanced system of hyper-responsive hydraulic joints and a suite of sensors, accelerometers and gyroscopes, the BigDog's most stunning achievement is it's ability to walk, climb and maintain its balance on diverse terrain, even after slipping on ice or receiving a kick to one side. All while carrying several hundreds of pounds of supplies on its "back."

Meet BigDog, a mechanical mutt that does more than snare Frisbees and irrigate fire hydrants. It totes hundreds of pounds of gear so soldiers won't have to, and it will never spook under fire. Developed by Boston Dynamics with funding from the U.S. military, the BigDog prototype is arguably the world's most ambitious legged robot.