Humans have always feared animals that roamed the dark. Anything that conducts its business after sundown must surely be malevolent in nature. Bats, in particular, have been held in very low esteem for centuries, especially in the western world. In the realms of human imagination, bats are often little more than creatures of evil, associated with the deepest night and devilish goings-on.
At the bottom of a freshwater stream in Britain, a thin, elongated fish undulates through the water. It looks a bit like an eel, but closer examination reveals it is something much different, and much stranger. It only has a single nostril (on the top of its head) and its large suctorial mouth is bristling with sharp, inward-pointing teeth of varying sizes, arranged in neat concentric circles.