If you ride a bicycle, be proud. Humans riding on bicycles are more energy-efficient than any other animal and any other form of transportation. Vance Tucker of Duke University compared bicyclists to humans and animals running, birds flying and fish swimming, as well as to people in motor-powered cars, boats, trains and planes (J. Exp. Bio, 1973;68(9):689-709). The less energy per weight you use to travel over a distance, the more energy-efficient you are. Tucker found that the most efficient creature without mechanical help is a condor. With mechanical help, the cyclist comes out on top.