Why do humans have fingerprints?
Fingerprints follow us our entire lives. Each little smudge singles us out as distinct individuals among billions of other human beings, or at least that's what we've always been told.
Identical twins also have different fingerprints. All of those unique loops, ridges, whorls and arches were writ inside the womb by pressure on the developing skin.
The outer epidermis and the inner subcutaneous tissue sandwich the dermal cell layer between them like a slice of cheese between two slabs of bread. As the pressure builds, this slice of cheese compresses and buckles, erupting in random surface patterns.
Fingerprints help us feel fine textures and tiny objects. See, when you feel particularly subtle features, your sense of touch depends on skin vibrations that arise as your fingertips move across the fine textures.
A ridged fingertip moving across a surface produces vibration frequencies that are detected by special nerve endings called pacinian corpuscles. These nerve endings pass this information on to sensory neurons that signal the brain. Burn those prints off and you might dodge a jail sentence, but good luck appreciating, and feeling, the finer things in life.
So that's why you have fingerprints. Now dip them in ink, dust and go share them with the world.