There is a very good reason that these robots have walking systems that are eerily similar to human legs. Boston Dynamics was founded by Marc Raibert. For those that don't reconize the name, Marc was the founder and principal investigator of the
MIT Leg Lab, which conducted some of the earliest (and arguably best) research in walking dynamics. They sourced most of the significant early developments running and hopping robots. Boston Dynamics was started as an effort to begin to commercialize some of this early technology, and to develop marketable applications. Oh yeah, and Marc's stuff is also always just unbelievably cool (just wait until you see their compact rope ascender!).
-dave