When you look at a kingfisher’s beak and head, do you think of a bullet train? Japanese engineers did. They built a fast train, but there was an unforeseen problem: the blunt nose of the train didn’t move through air efficiently enough. Instead of cutting through, it pushed. In narrow tunnels the pushed-ahead air would compress and pressurize. As the train left the tunnel, the air would rapidly expand, resulting in a dish-rattling sonic boom.
Kingfishers deal with a much “thicker” medium than air. They regularly dive after fish, and if they pushed water ahead of themselves the way bullet trains pushed air, the resistance would make it difficult to capture anything. But their beaks gradually increase in diameter, enabling them to slice through the water so efficiently that the birds hardly make a splash.
By modeling bullet train noses on kingfisher beaks, West Japan Railway Company engineers created the 500 series, which entered service in 1997. The trains are quieter, 10 percent faster and use 15 percent less electricity.
Wired has a slideshow of “9 Design Tricks Borrowed From Biology,” and while I think the kingfisher example is the best, the bendy concrete is pretty cool too.