BigDog is powered by a gasoline engine that drives a hydraulic actuation system. BigDog’s legs are articulated like an animal’s, and have compliant elements that absorb shock and recycle energy from one step to the next. BigDog is the size of a large dog or small mule, measuring 1 meter long, 0.7 meters tall and 75 kg weight.

Make sure to look at the video. Fantastic little machine, super impressive, especially when the guys kick it around and you see the speed and technique of the moving legs to keep the “BigDog” standing.