The Unexpected Origin of Fingers

Five digits radiating from a palm, an arrangement both flexible and strong—capable of playing a piano, wielding a hammer, offering a comforting touch. The hand is our most familiar body part, central to most everyday tasks, from dressing and driving to cooking and texting. Yet from an evolutionary stand-point, it remains largely mysterious, particularly when it comes to the earliest stage of its origin. Other four-limbed creatures—tetrapods, as they are known—have hands that look and function quite differently than ours do. In birds and bats, they help to form delicate wings; in elephants, they support limbs as big around as tree trunks. But the basic structure is the same. In 1859 Charles Darwin remarked on the similarities in On the Origin of Species: “What can be more curious than that the hand of a man, formed for grasping, that of a mole for digging, the leg of the horse, the paddle of the porpoise, and the wing of the bat, should all be constructed on the same pattern, and should include the same bones, in the same relative positions?”