Photo: 5-week-old human embryo showing tail. Credit: Ed Uthman, Wikimedia Commons


How Humans Lost Their Tail, Twice

You started off your life with a tail, but now just have a tailbone. This is why that happened.

Published On 12/05/2016
12:00 PM EST
Illustration: The early double-tailed fish Aetheretmon swimming alongside a singled-tailed modern pufferfish and an early tetrapod in a 350-million-year old river. Credit: John Megahan