Big robotic dog

This prototype of a 4-legged robot that can navigate rugged, complex and slippery terrain was developed by Boston Dynamics with help from Foster Miller, the Jet Propulsion Laboratory, and the Harvard University Concord Field Station. Development is funded by the DARPA Defense Sciences Office.
BigDog is the size of a large dog or small mule, measuring 1 meter/40” long, 0.7 meters/ 28” tall and 75 kg/ 165 pounds weight. The robot is powered by a gasoline engine driving a hydraulic actuation system; its legs are articulated like an animal’s, and have elements that absorb shock and recycle energy from one step to the next just as animals and humans do.