In understanding some of the changes that took place over the course of evolutionary history that led to the differences between humans and other primates, we had the kids discuss and experience some different forms of primate locomotion–that is, walking. To do this, we had the clans divide up as teams and assigned each one a locomotion style. One clan competed as baboons, which meant they had to run as terrestrial quadrupeds, down on all fours. Another clan competed as chimp or gorilla knuckle walkers, placing weight on their first set of knuckles as they raced along. The other two clans were bipeds, but they were handicapped to demonstrate how specialized bipedalism is (since we are, of course, evolved to be very efficient at what we do regularly). One clan had to run with extra long kangaroo-like feet by wearing swim fins. The other had to wear a backpack of bricks on their front to demonstrate how we carry all of our weight over our knees (our center of gravity). For all you moms out there, this latter clan should have gotten some insight into what it’s like to try to move efficiently while leaning back to accommodate that bowling ball during pregnancy, albeit for a much shorter period of time! The goal of the race was to reach a patch of delicious wheat grass, which they were free to eat upon reaching (video of primate races and devouring the “kill”). Of course, this was only truly motivating for the baboons, since the only true grass-eaters among primates are a group of baboons called gelada baboons. The knuckle-walkers and bipeds were far less interested in the grass treat and so lagged behind. After the race, we took a quadrupedal tour of the school yard and talked about some of the aches and pains we were experiencing in our necks, backs, and fingers and what some of the anatomical differences between us and other primates might be that leads to different modes of locomotion to be efficient for different types of primates.