A kaleidoscope of emotions unfolds as I watch this video of BigDog, the four-legged pack robot.

According to Boston Dynamics, the robotics company that's been developing the system since 2006, BigDog clocks in at four miles-per-hour, carries a load of 340 pounds and can scale a 35-degree incline. (Its motor also makes it sound like one of those dogs with bees in their mouths so when they bark they shoot bees at you.)

Now I don't know how many hours of video the DARPA-funded honchos at BD had to shoot before contributing this clip to the already vast trove of robot porn, but as it stands it's astounding to see this 165-pound metal greyhound trudge up forested hills and across snowy landscapes, pick its way over a pile of cinder blocks and bound over a series of faux crevasses.