I think that one of the things that really separates us from the primates is that we are tool builders. I read a story that measured the efficiency of locomotion for various species on the planet. The condor used the least energy to move a kilometer and humas came in with a rather unimpressing showing; about a third down the list. Not to proud a showing for the crown of creation.
That didn't look so good, but then someone at Scientific American had the insight to test the efficiency of locomotion for a man on a bicycle, and a man on a bicycle blew the charts away surpassing the condor, which is the most efficient.(speech - Steve Jobs - mlfilms.com)