A violin cry

摘要

This common crane, preening itself at Lake Ganzen in Germany, has an extraordinary adaptation. Its windpipe, or trachea, is three or more times as long as would be expected for a bird of this size-even one with a long neck. Instead of going straight from the bill to the lungs as you might expect, the crane's trachea forms coils inside the body before getting there. If you have heard the penetrating, haunting call of a crane - it carries for several kilometres - you might suspect that the trachea is some sort of echo chamber for amplifying the cry, a kind of biological trombone. But different species of cranes have different amounts of coiling, and yet they can all make extremely loud calls.