The Most Efficient Traveler in Nature Isn’t a Bird or a Fish, It’s Us
At first glance, humans don’t seem built for great travel. We can’t fly, our swimming is clumsy, and even the fastest among us are slow compared to most animals. But that changes the moment we get on a bike. On two wheels, we become one of the most energy-efficient movers in the natural world. A 1973 study—later popularized in Scientific American—even ranked humans on bicycles ahead of nearly every animal and machine when it came to energy used per kilogram per kilometer.
The reason comes down to physics. Walking and running take work because every step means lifting and dropping our body weight. Flying creatures ride air currents, and fish move through water with built-in buoyancy that eases gravity’s pull. On a bike, though, wheels carry the load. Instead of lifting ourselves, we roll forward, turning raw effort into smooth motion. That simple shift makes cycling one of the most elegant tricks evolution never quite managed to invent on its own.
Physics of Pedaling
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Bicycles work so well because they let us bend the rules of physics just a bit. Two forces matter in travel: gravity and forward propulsion. On foot, both demand energy, as they require holding your body upright and pushing it forward step by step. A bike removes most of the struggle against gravity and allows you to focus on moving ahead. Tyson Hedrick, a comparative physiologist at the University of North Carolina, says that bicycles make us “hyperefficient terrestrial locomotors” because they mimic the ease of swimming through water.
Still, we have one big disadvantage: drag. Our human shape wasn’t built for aerodynamics. Cyclists may pedal with incredible efficiency, but the air resistance is brutal compared to streamlined fish like bluefin tuna. The fix is surprisingly simple. Velomobiles—recumbent bicycles enclosed in aerodynamic shells—cut through the air with far less drag. With the wind resistance reduced, riders use even less energy, turning the act of cycling into something closer to gliding. In tests, their efficiency approaches that of soaring birds, making humans on wheels one of the most graceful travelers on land.
Comparing Us to Nature’s Best
When you plot all travelers on a chart, from cows and horses to airplanes and fish, bicycling humans take a shocking lead. A person walking uses about 0.75 calories per gram per kilometer. On a bike, that drops to roughly 0.15 calories. Even jet planes, which carry tons of passengers, aren’t as efficient per unit of energy when measured the same way. One Reddit commenter joked that cars might need to be measured in “cowpower” instead of horsepower since they’re closer to livestock in efficiency.
Bikes have a secret helper in infrastructure. Smooth asphalt roads make cycling efficient, but take away that surface and rolling resistance skyrockets. Off-road, the balance shifts. Still, on the open road, no creature on Earth can travel as far, as fast, and as cheaply on energy as a person pedaling a bicycle.
Rethinking How We Move
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All this data makes one thing clear: we’ve underestimated how effective human-powered travel can be. Cycling isn’t just eco-friendly or good exercise; it’s a masterclass in efficiency. It challenges the assumption that bigger, faster machines always mean better travel. Even when compared to trains, planes, and automobiles, a simple bike stands out as the most innovative way to move from point A to point B using the least amount of energy.
If we treated bike travel with the same seriousness we give to cars, building better infrastructure and safer roads, we’d see cities transformed. People could travel faster and healthier, all at a fraction of the energy cost. It’s funny to think that the answer to moving efficiently has been under our noses (and between our legs) for over a century.