Reading the Leftovers

Each vestigial part is a clue about who your ancestors were:

• Wisdom teeth point to a past of tough, raw food and bigger jaws.
• The appendix points to a long partnership with gut bacteria.
• The palmaris longus points to a life spent gripping branches.
• Goosebumps point to a body once covered in thick fur.

These parts linger because evolution has no eraser. It can only favor what helps survival now, and a harmless leftover gives it little reason to act.