In the 1980s, a bioengineer named Norm Heglund was doing field work in Kenya, hoping to uncover the secrets of locomotion. It was a good gig. Heglund and his team spent their days shooting wild animals with tranquilizer darts in Kenya’s national parks then dragging them back to a research station, run by the East Africa Veterinary Research Organization, in nearby Muguga for testing.Every day, the wives of local colleagues stopped by the lab to chit chat. They carried impossibly huge bundles of food, clothing, or other supplies perfectly balanced on top of their heads. During one lunch break, a few weeks into his stay, he realized something.