Scientists have just found out what you always wanted to know: why do fingernails, when nibbled or torn, tend to tear across the nail rather than downwards towards the nail bed?
By analyzing nails under the electron microscope, the reason became clear: nails are made of three layers containing the protein keratin. The keratin fibres have a specific arrangement that prevents breaks from running down the nail and also gives the nail tremendous strength. Without this arrangement, according to one of the researchers, 'every tear would damage our nail bed, inflicting great pain and incurring infection'. A similar pattern is seen in horses' hooves—which is just as well—because if cracks were to run upwards instead of across in a horse's hoof, it could lead to infection, lameness and death.
How could anyone say that this crucial design feature of hooves and fingernails has come about by accident? The evidence surely shouts 'Designer'.